library(rmarkdown);  library(knitr);  library(readxl);  library(tidyverse);  library(survival)

 library(survminer); library(ggsurvfit); library(gtsummary);    library(pacman) ; library(ggplot2)

Estimador de Kaplan-Meier

Dados sem Sensura

Consideremos este dado hipotético (sem sensura)

Temp_0 = c(3, 18, 29, 54, 60, 84, 110, 112, 116, 123, 134, 145, 151, 151, 158, 173, 194, 214, 329, 331, 
           371, 408, 490, 514, 541, 55, 688, 780, 801, 858, 887, 998);  Status_0 = rep(1, 32)

Estimador Kaplan-Meier

# Tempo de sobrevivência ← Surv(Temp_0, Status_0) 

E_KM_0 = survfit(Surv(Temp_0, Status_0)~1);   E_KM_0;   summary(E_KM_0)
## Call: survfit(formula = Surv(Temp_0, Status_0) ~ 1)
## 
##       n events median 0.95LCL 0.95UCL
## [1,] 32     32    166     134     408
## Call: survfit(formula = Surv(Temp_0, Status_0) ~ 1)
## 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##     3     32       1   0.9688  0.0308      0.91030        1.000
##    18     31       1   0.9375  0.0428      0.85727        1.000
##    29     30       1   0.9062  0.0515      0.81068        1.000
##    54     29       1   0.8750  0.0585      0.76760        0.997
##    55     28       1   0.8438  0.0642      0.72688        0.979
##    60     27       1   0.8125  0.0690      0.68792        0.960
##    84     26       1   0.7812  0.0731      0.65038        0.938
##   110     25       1   0.7500  0.0765      0.61402        0.916
##   112     24       1   0.7188  0.0795      0.57870        0.893
##   116     23       1   0.6875  0.0819      0.54428        0.868
##   123     22       1   0.6562  0.0840      0.51070        0.843
##   134     21       1   0.6250  0.0856      0.47789        0.817
##   145     20       1   0.5938  0.0868      0.44580        0.791
##   151     19       2   0.5312  0.0882      0.38367        0.736
##   158     17       1   0.5000  0.0884      0.35359        0.707
##   173     16       1   0.4688  0.0882      0.32415        0.678
##   194     15       1   0.4375  0.0877      0.29536        0.648
##   214     14       1   0.4062  0.0868      0.26723        0.618
##   329     13       1   0.3750  0.0856      0.23976        0.587
##   331     12       1   0.3438  0.0840      0.21298        0.555
##   371     11       1   0.3125  0.0819      0.18692        0.522
##   408     10       1   0.2812  0.0795      0.16164        0.489
##   490      9       1   0.2500  0.0765      0.13719        0.456
##   514      8       1   0.2188  0.0731      0.11365        0.421
##   541      7       1   0.1875  0.0690      0.09115        0.386
##   688      6       1   0.1562  0.0642      0.06985        0.350
##   780      5       1   0.1250  0.0585      0.04998        0.313
##   801      4       1   0.0938  0.0515      0.03193        0.275
##   858      3       1   0.0625  0.0428      0.01633        0.239
##   887      2       1   0.0312  0.0308      0.00454        0.215
##   998      1       1   0.0000     NaN           NA           NA
plot(E_KM_0, conf.int = F, xlab = "Dias", ylab = "Sobrevivências", main = "Estimador de Kaplan-Meier")

Dados com Censura

Consideremos este dado hipotético (com sensura)

Temp_1 = c(16, 18, 21, 21, 22, 25, 29, 35, 37, 39, 40, 50, 52, 54, 60, 80, 80, 81, 83, 84, 85)  

Status_1 = c(1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0) # 0 - Censura; 1 - Evento

Surv(Temp_1, Status_1) # ← Surv(Temp_0, Status_0) 
##  [1] 16  18  21+ 21  22  25+ 29  35  37  39  40  50+ 52  54  60  80+ 80  81+ 83 
## [20] 84  85+

Estimador Kaplan-Meier

E_KM_1 = survfit(Surv(Temp_1, Status_1)~1);      E_KM_1;        summary(E_KM_1)  
## Call: survfit(formula = Surv(Temp_1, Status_1) ~ 1)
## 
##       n events median 0.95LCL 0.95UCL
## [1,] 21     15     52      37      NA
## Call: survfit(formula = Surv(Temp_1, Status_1) ~ 1)
## 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##    16     21       1   0.9524  0.0465       0.8655        1.000
##    18     20       1   0.9048  0.0641       0.7875        1.000
##    21     19       1   0.8571  0.0764       0.7198        1.000
##    22     17       1   0.8067  0.0869       0.6531        0.996
##    29     15       1   0.7529  0.0963       0.5859        0.968
##    35     14       1   0.6992  0.1034       0.5232        0.934
##    37     13       1   0.6454  0.1085       0.4642        0.897
##    39     12       1   0.5916  0.1120       0.4082        0.857
##    40     11       1   0.5378  0.1140       0.3550        0.815
##    52      9       1   0.4781  0.1160       0.2972        0.769
##    54      8       1   0.4183  0.1158       0.2431        0.720
##    60      7       1   0.3585  0.1137       0.1926        0.667
##    80      6       1   0.2988  0.1093       0.1459        0.612
##    83      3       1   0.1992  0.1092       0.0680        0.583
##    84      2       1   0.0996  0.0891       0.0172        0.575
plot(E_KM_1, conf.int = F, mark.time = T, xlab = "Dias", ylab = "Sobrevivências",
     main = "Estimador ede Kaplan-Meier")

Exemplos Reais - Aplicação

A base de dados diabetic é um conjunto de dados clássico amplamente utilizado em Análise de Sobrevivência, estando disponível no pacote survival do R. O estudo investiga o tempo até à ocorrência de perda visual grave em pacientes com retinopatia diabética, avaliando a eficácia de um tratamento a laser em comparação com a ausência de tratamento, com o objetivo de analisar se o tratamento reduz o risco de progressão da doença ao longo do tempo.

Os dados são provenientes de um ensaio clínico conduzido nos Estados Unidos, no âmbito do Early Treatment Diabetic Retinopathy Study (ETDRS), um grande estudo multicêntrico desenvolvido para avaliar estratégias terapêuticas em doentes com diabetes e complicações oculares.

data(diabetic, package = "survival");   paged_table(diabetic) # Visualizar a Base de dados

Estimador Kaplan-Meier

# survival::survfit - evitar conflitos com outras funções de mesmo nome em outros pacotes.

E_KM_2 = survival::survfit(Surv(time, status) ~ 1, data = diabetic);  summary(E_KM_2)
## Call: survfit(formula = Surv(time, status) ~ 1, data = diabetic)
## 
##   time n.risk n.event survival std.err lower 95% CI upper 95% CI
##   0.30    394       1    0.997 0.00253        0.993        1.000
##   0.60    393       1    0.995 0.00358        0.988        1.000
##   0.83    392       1    0.992 0.00438        0.984        1.000
##   1.33    391       1    0.990 0.00505        0.980        1.000
##   1.43    390       1    0.987 0.00564        0.976        0.998
##   1.50    385       2    0.982 0.00667        0.969        0.995
##   1.57    383       1    0.980 0.00713        0.966        0.994
##   1.63    382       2    0.974 0.00796        0.959        0.990
##   1.70    380       3    0.967 0.00906        0.949        0.985
##   1.73    377       1    0.964 0.00939        0.946        0.983
##   1.77    376       1    0.962 0.00971        0.943        0.981
##   1.80    375       1    0.959 0.01001        0.940        0.979
##   1.90    374       1    0.957 0.01031        0.937        0.977
##   1.97    373       1    0.954 0.01060        0.933        0.975
##   2.10    372       1    0.951 0.01087        0.930        0.973
##   2.17    371       1    0.949 0.01114        0.927        0.971
##   2.67    370       1    0.946 0.01140        0.924        0.969
##   2.70    369       1    0.944 0.01166        0.921        0.967
##   2.83    367       1    0.941 0.01191        0.918        0.965
##   2.90    366       1    0.939 0.01215        0.915        0.963
##   3.67    365       1    0.936 0.01238        0.912        0.961
##   4.10    363       1    0.933 0.01262        0.909        0.958
##   4.27    362       1    0.931 0.01284        0.906        0.956
##   4.30    361       1    0.928 0.01306        0.903        0.954
##   4.97    360       1    0.926 0.01328        0.900        0.952
##   5.33    359       1    0.923 0.01349        0.897        0.950
##   5.43    358       1    0.921 0.01370        0.894        0.948
##   5.67    357       1    0.918 0.01390        0.891        0.946
##   5.73    356       1    0.915 0.01410        0.888        0.943
##   5.77    355       1    0.913 0.01429        0.885        0.941
##   5.83    354       1    0.910 0.01448        0.882        0.939
##   5.90    353       1    0.908 0.01467        0.879        0.937
##   6.10    350       1    0.905 0.01485        0.876        0.935
##   6.13    349       1    0.902 0.01504        0.873        0.932
##   6.20    348       1    0.900 0.01521        0.871        0.930
##   6.30    347       1    0.897 0.01539        0.868        0.928
##   6.53    346       1    0.895 0.01556        0.865        0.926
##   6.57    345       2    0.889 0.01590        0.859        0.921
##   6.90    343       1    0.887 0.01606        0.856        0.919
##   7.07    342       1    0.884 0.01622        0.853        0.917
##   7.10    341       1    0.882 0.01638        0.850        0.914
##   7.60    339       1    0.879 0.01654        0.847        0.912
##   7.90    338       1    0.877 0.01669        0.844        0.910
##   8.30    335       2    0.871 0.01700        0.839        0.905
##   8.83    333       1    0.869 0.01715        0.836        0.903
##   9.40    332       1    0.866 0.01729        0.833        0.901
##   9.60    331       1    0.863 0.01744        0.830        0.898
##   9.63    330       1    0.861 0.01758        0.827        0.896
##   9.87    328       1    0.858 0.01772        0.824        0.894
##   9.90    326       3    0.850 0.01814        0.815        0.887
##  10.27    323       1    0.848 0.01827        0.813        0.884
##  10.33    322       1    0.845 0.01840        0.810        0.882
##  10.80    316       1    0.842 0.01854        0.807        0.879
##  10.97    315       1    0.840 0.01867        0.804        0.877
##  11.07    314       1    0.837 0.01880        0.801        0.875
##  11.30    313       1    0.834 0.01893        0.798        0.872
##  12.20    312       1    0.832 0.01906        0.795        0.870
##  12.73    311       1    0.829 0.01918        0.792        0.867
##  12.93    310       1    0.826 0.01931        0.789        0.865
##  13.10    309       1    0.824 0.01943        0.786        0.863
##  13.33    308       1    0.821 0.01955        0.784        0.860
##  13.37    307       1    0.818 0.01967        0.781        0.858
##  13.57    306       1    0.816 0.01978        0.778        0.855
##  13.77    305       2    0.810 0.02001        0.772        0.850
##  13.80    303       1    0.808 0.02012        0.769        0.848
##  13.83    302       4    0.797 0.02056        0.758        0.838
##  13.87    298       1    0.794 0.02066        0.755        0.836
##  13.90    297       1    0.792 0.02076        0.752        0.833
##  13.97    296       1    0.789 0.02086        0.749        0.831
##  14.00    295       1    0.786 0.02096        0.746        0.828
##  14.10    294       1    0.784 0.02106        0.743        0.826
##  14.27    293       1    0.781 0.02116        0.740        0.823
##  14.30    292       1    0.778 0.02126        0.738        0.821
##  14.37    291       1    0.775 0.02135        0.735        0.818
##  14.80    289       1    0.773 0.02144        0.732        0.816
##  15.83    288       1    0.770 0.02154        0.729        0.814
##  17.73    286       1    0.767 0.02163        0.726        0.811
##  18.03    285       2    0.762 0.02181        0.720        0.806
##  18.43    283       1    0.759 0.02190        0.718        0.804
##  18.70    282       1    0.757 0.02199        0.715        0.801
##  18.93    278       1    0.754 0.02207        0.712        0.798
##  19.00    277       1    0.751 0.02216        0.709        0.796
##  19.40    276       1    0.748 0.02225        0.706        0.793
##  20.17    274       1    0.746 0.02233        0.703        0.791
##  21.10    271       1    0.743 0.02242        0.700        0.788
##  21.57    270       1    0.740 0.02251        0.697        0.786
##  21.90    268       1    0.737 0.02259        0.695        0.783
##  21.97    267       1    0.735 0.02267        0.692        0.781
##  22.00    266       2    0.729 0.02284        0.686        0.775
##  22.13    264       1    0.726 0.02292        0.683        0.773
##  22.20    263       1    0.724 0.02300        0.680        0.770
##  22.23    262       1    0.721 0.02307        0.677        0.768
##  24.43    259       1    0.718 0.02315        0.674        0.765
##  24.73    258       1    0.715 0.02323        0.671        0.762
##  25.30    257       1    0.713 0.02331        0.668        0.760
##  25.63    256       1    0.710 0.02338        0.665        0.757
##  25.80    255       1    0.707 0.02345        0.663        0.755
##  25.93    252       1    0.704 0.02353        0.660        0.752
##  26.17    251       1    0.701 0.02360        0.657        0.749
##  26.20    250       1    0.699 0.02367        0.654        0.747
##  26.23    249       1    0.696 0.02374        0.651        0.744
##  26.37    248       1    0.693 0.02381        0.648        0.741
##  26.47    247       1    0.690 0.02388        0.645        0.739
##  27.60    244       1    0.687 0.02395        0.642        0.736
##  29.97    241       1    0.684 0.02402        0.639        0.733
##  30.20    240       1    0.682 0.02409        0.636        0.731
##  30.40    239       1    0.679 0.02416        0.633        0.728
##  30.83    238       1    0.676 0.02422        0.630        0.725
##  31.30    235       1    0.673 0.02429        0.627        0.722
##  31.63    232       1    0.670 0.02436        0.624        0.720
##  33.63    225       2    0.664 0.02450        0.618        0.714
##  33.90    223       1    0.661 0.02457        0.615        0.711
##  34.37    220       1    0.658 0.02464        0.612        0.708
##  34.57    219       1    0.655 0.02471        0.609        0.705
##  35.53    218       1    0.652 0.02478        0.605        0.703
##  38.40    207       1    0.649 0.02486        0.602        0.700
##  38.47    206       1    0.646 0.02494        0.599        0.697
##  38.57    205       2    0.640 0.02509        0.592        0.691
##  38.87    195       1    0.636 0.02518        0.589        0.688
##  41.40    185       1    0.633 0.02527        0.585        0.684
##  42.17    177       2    0.626 0.02549        0.578        0.678
##  42.33    167       1    0.622 0.02561        0.574        0.674
##  42.43    166       1    0.618 0.02573        0.570        0.671
##  43.03    161       1    0.614 0.02585        0.566        0.667
##  43.33    158       1    0.611 0.02598        0.562        0.664
##  43.70    155       1    0.607 0.02611        0.557        0.660
##  46.20    145       1    0.602 0.02626        0.553        0.656
##  46.27    140       1    0.598 0.02643        0.548        0.652
##  46.43    136       1    0.594 0.02660        0.544        0.648
##  46.63    133       1    0.589 0.02677        0.539        0.644
##  48.30    128       1    0.585 0.02695        0.534        0.640
##  48.43    127       1    0.580 0.02713        0.529        0.636
##  48.87    125       1    0.575 0.02731        0.524        0.631
##  54.10    104       1    0.570 0.02760        0.518        0.627
##  54.27     99       1    0.564 0.02791        0.512        0.622
##  59.80     56       1    0.554 0.02918        0.500        0.614
##  61.83     51       1    0.543 0.03056        0.486        0.606
##  63.33     43       1    0.531 0.03235        0.471        0.598

Curva de Sobrevivência

ggsurvfit(E_KM_2, color = "cadetblue") + 
  add_censor_mark(color = "cadetblue") + 
  add_confidence_interval(fill = "cadetblue") + 
  add_quantile(y_value = 0.5, linetype = "dashed", color = "grey30") + 
  labs(x = "Tempo (dias)", y = "Probabilidade de sobrevivência") + 
  scale_ggsurvfit(x_scales = list(breaks = seq(0, 2250, by = 250))) + 
  add_risktable(stats_label = c("Em risco", "Eventos")) + 
  theme(axis.title = element_text(size = 11), 
        axis.title.x = element_text(margin = margin(5,5,15,5)))

Comparação entre os grupos

E_KM_3 = survival::survfit(Surv(time, status) ~ trt, data = diabetic);  summary(E_KM_3)
## Call: survfit(formula = Surv(time, status) ~ trt, data = diabetic)
## 
##                 trt=0 
##   time n.risk n.event survival std.err lower 95% CI upper 95% CI
##   0.30    197       1    0.995 0.00506        0.985        1.000
##   0.60    196       1    0.990 0.00714        0.976        1.000
##   0.83    195       1    0.985 0.00872        0.968        1.000
##   1.33    194       1    0.980 0.01005        0.960        1.000
##   1.43    193       1    0.975 0.01121        0.953        0.997
##   1.50    190       1    0.969 0.01226        0.946        0.994
##   1.57    189       1    0.964 0.01323        0.939        0.991
##   1.63    188       2    0.954 0.01495        0.925        0.984
##   1.70    186       2    0.944 0.01645        0.912        0.977
##   1.80    184       1    0.939 0.01714        0.906        0.973
##   1.97    183       1    0.934 0.01780        0.899        0.969
##   2.17    182       1    0.928 0.01843        0.893        0.965
##   2.67    181       1    0.923 0.01903        0.887        0.961
##   2.83    179       1    0.918 0.01961        0.881        0.957
##   2.90    178       1    0.913 0.02016        0.874        0.953
##   3.67    177       1    0.908 0.02070        0.868        0.949
##   4.27    176       1    0.903 0.02121        0.862        0.945
##   4.30    175       1    0.898 0.02171        0.856        0.941
##   4.97    174       1    0.892 0.02219        0.850        0.937
##   5.33    173       1    0.887 0.02265        0.844        0.933
##   5.43    172       1    0.882 0.02310        0.838        0.929
##   5.83    171       1    0.877 0.02354        0.832        0.924
##   6.20    169       1    0.872 0.02396        0.826        0.920
##   6.53    168       1    0.867 0.02437        0.820        0.916
##   6.57    167       1    0.861 0.02477        0.814        0.911
##   6.90    166       1    0.856 0.02516        0.808        0.907
##   7.10    165       1    0.851 0.02554        0.802        0.903
##   7.60    164       1    0.846 0.02591        0.796        0.898
##   7.90    163       1    0.841 0.02626        0.791        0.894
##   8.30    161       1    0.835 0.02661        0.785        0.889
##   8.83    160       1    0.830 0.02695        0.779        0.885
##   9.40    159       1    0.825 0.02728        0.773        0.880
##   9.60    158       1    0.820 0.02761        0.767        0.876
##   9.63    157       1    0.814 0.02792        0.762        0.871
##   9.87    156       1    0.809 0.02822        0.756        0.867
##   9.90    155       2    0.799 0.02881        0.744        0.857
##  10.80    151       1    0.794 0.02910        0.738        0.853
##  10.97    150       1    0.788 0.02938        0.733        0.848
##  11.30    149       1    0.783 0.02966        0.727        0.843
##  12.20    148       1    0.778 0.02993        0.721        0.839
##  12.73    147       1    0.772 0.03019        0.715        0.834
##  13.37    146       1    0.767 0.03044        0.710        0.829
##  13.77    145       1    0.762 0.03069        0.704        0.824
##  13.83    144       3    0.746 0.03139        0.687        0.810
##  13.87    141       1    0.741 0.03161        0.681        0.805
##  13.90    140       1    0.735 0.03182        0.676        0.800
##  14.00    139       1    0.730 0.03203        0.670        0.796
##  14.10    138       1    0.725 0.03223        0.664        0.791
##  14.37    137       1    0.719 0.03243        0.659        0.786
##  14.80    135       1    0.714 0.03262        0.653        0.781
##  15.83    134       1    0.709 0.03281        0.647        0.776
##  18.03    133       2    0.698 0.03317        0.636        0.766
##  18.43    131       1    0.693 0.03334        0.630        0.761
##  18.93    129       1    0.687 0.03351        0.625        0.756
##  19.00    128       1    0.682 0.03368        0.619        0.751
##  19.40    127       1    0.677 0.03384        0.614        0.746
##  21.10    125       1    0.671 0.03400        0.608        0.741
##  21.90    124       1    0.666 0.03415        0.602        0.736
##  21.97    123       1    0.660 0.03430        0.597        0.731
##  22.00    122       2    0.650 0.03458        0.585        0.721
##  22.13    120       1    0.644 0.03472        0.580        0.716
##  22.20    119       1    0.639 0.03484        0.574        0.711
##  22.23    118       1    0.633 0.03497        0.568        0.706
##  24.73    116       1    0.628 0.03509        0.563        0.701
##  25.30    115       1    0.622 0.03521        0.557        0.695
##  25.93    113       1    0.617 0.03532        0.551        0.690
##  26.17    112       1    0.611 0.03543        0.546        0.685
##  26.37    111       1    0.606 0.03554        0.540        0.680
##  26.47    110       1    0.600 0.03564        0.534        0.675
##  27.60    108       1    0.595 0.03574        0.529        0.669
##  29.97    106       1    0.589 0.03584        0.523        0.664
##  30.40    105       1    0.584 0.03594        0.517        0.659
##  31.30    103       1    0.578 0.03603        0.512        0.653
##  31.63    101       1    0.572 0.03613        0.506        0.648
##  33.63     98       1    0.566 0.03623        0.500        0.642
##  35.53     96       1    0.561 0.03633        0.494        0.636
##  38.40     91       1    0.554 0.03645        0.487        0.631
##  38.57     90       2    0.542 0.03666        0.475        0.619
##  41.40     80       1    0.535 0.03683        0.468        0.613
##  42.17     76       1    0.528 0.03701        0.460        0.606
##  42.33     70       1    0.521 0.03724        0.453        0.599
##  43.03     68       1    0.513 0.03747        0.445        0.592
##  43.33     66       1    0.505 0.03770        0.437        0.585
##  43.70     65       1    0.497 0.03792        0.428        0.578
##  46.20     61       1    0.489 0.03816        0.420        0.570
##  46.27     58       1    0.481 0.03842        0.411        0.562
##  46.63     55       1    0.472 0.03871        0.402        0.554
##  48.30     53       1    0.463 0.03899        0.393        0.546
##  48.43     52       1    0.454 0.03924        0.384        0.538
##  54.10     42       1    0.444 0.03977        0.372        0.529
##  54.27     40       1    0.432 0.04029        0.360        0.519
##  59.80     23       1    0.414 0.04270        0.338        0.506
##  61.83     21       1    0.394 0.04498        0.315        0.493
## 
##                 trt=1 
##   time n.risk n.event survival std.err lower 95% CI upper 95% CI
##   1.50    195       1    0.995 0.00512        0.985        1.000
##   1.70    194       1    0.990 0.00722        0.976        1.000
##   1.73    193       1    0.985 0.00881        0.967        1.000
##   1.77    192       1    0.979 0.01015        0.960        1.000
##   1.90    191       1    0.974 0.01132        0.952        0.997
##   2.10    190       1    0.969 0.01237        0.945        0.994
##   2.70    189       1    0.964 0.01332        0.938        0.991
##   4.10    187       1    0.959 0.01421        0.931        0.987
##   5.67    186       1    0.954 0.01504        0.925        0.984
##   5.73    185       1    0.949 0.01582        0.918        0.980
##   5.77    184       1    0.943 0.01655        0.912        0.976
##   5.90    183       1    0.938 0.01725        0.905        0.973
##   6.10    181       1    0.933 0.01791        0.899        0.969
##   6.13    180       1    0.928 0.01855        0.892        0.965
##   6.30    179       1    0.923 0.01916        0.886        0.961
##   6.57    178       1    0.918 0.01974        0.880        0.957
##   7.07    177       1    0.912 0.02030        0.873        0.953
##   8.30    174       1    0.907 0.02085        0.867        0.949
##   9.90    171       1    0.902 0.02139        0.861        0.945
##  10.27    170       1    0.897 0.02191        0.855        0.941
##  10.33    169       1    0.891 0.02241        0.848        0.936
##  11.07    165       1    0.886 0.02292        0.842        0.932
##  12.93    164       1    0.880 0.02341        0.836        0.928
##  13.10    163       1    0.875 0.02388        0.829        0.923
##  13.33    162       1    0.870 0.02433        0.823        0.919
##  13.57    161       1    0.864 0.02478        0.817        0.914
##  13.77    160       1    0.859 0.02520        0.811        0.910
##  13.80    159       1    0.853 0.02562        0.805        0.905
##  13.83    158       1    0.848 0.02602        0.799        0.901
##  13.97    157       1    0.843 0.02641        0.792        0.896
##  14.27    156       1    0.837 0.02678        0.786        0.891
##  14.30    155       1    0.832 0.02715        0.780        0.887
##  17.73    153       1    0.826 0.02751        0.774        0.882
##  18.70    152       1    0.821 0.02786        0.768        0.877
##  20.17    148       1    0.815 0.02822        0.762        0.873
##  21.57    146       1    0.810 0.02858        0.756        0.868
##  24.43    143       1    0.804 0.02893        0.749        0.863
##  25.63    142       1    0.798 0.02928        0.743        0.858
##  25.80    141       1    0.793 0.02961        0.737        0.853
##  26.20    139       1    0.787 0.02994        0.731        0.848
##  26.23    138       1    0.781 0.03026        0.724        0.843
##  30.20    135       1    0.776 0.03059        0.718        0.838
##  30.83    134       1    0.770 0.03090        0.712        0.833
##  33.63    127       1    0.764 0.03125        0.705        0.828
##  33.90    126       1    0.758 0.03158        0.698        0.822
##  34.37    124       1    0.752 0.03191        0.692        0.817
##  34.57    123       1    0.746 0.03223        0.685        0.811
##  38.47    116       1    0.739 0.03259        0.678        0.806
##  38.87    110       1    0.732 0.03298        0.670        0.800
##  42.17    101       1    0.725 0.03344        0.662        0.794
##  42.43     97       1    0.718 0.03392        0.654        0.787
##  46.43     80       1    0.709 0.03466        0.644        0.780
##  48.87     75       1    0.699 0.03547        0.633        0.772
##  63.33     25       1    0.671 0.04371        0.591        0.763
summary(E_KM_3, times = c(500, 1000)); survdiff(Surv(time, status) ~ trt, data = diabetic)
## Call: survfit(formula = Surv(time, status) ~ trt, data = diabetic)
## 
##                 trt=0 
##      time n.risk n.event survival
## 
##                 trt=1 
##      time n.risk n.event survival
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic)
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197      101     71.8      11.9      22.2
## trt=1 197       54     83.2      10.3      22.2
## 
##  Chisq= 22.2  on 1 degrees of freedom, p= 2e-06

Curva de Sobrevivência

ggsurvfit(E_KM_3) + add_censor_mark() + 
  add_confidence_interval() + 
  add_quantile(y_value = 0.5, linetype = "dashed", color = "grey30") + 
  labs(x = "Tempo (dias)", y = "Probabilidade de sobrevivência") + 
  scale_ggsurvfit(x_scales = list(breaks = seq(0, 90, by = 10))) + 
  add_risktable(stats_label = c("Em risco", "Eventos")) + 
  theme(
    legend.position = "inside",
    legend.position.inside = c(0.05, 0.05),        # Canto inferior esquerdo
    legend.justification = c(0, 0),                # Ancora o canto no ponto escolhido
    legend.background = element_rect(fill = "white", colour = "grey70", linewidth = 0.4),
   legend.text = element_text(size = 10),
    legend.direction = "vertical",               # Orientação da Legenda
    legend.box = "vertical",                     # garante a Orientação
  legend.margin = margin(4, 6, 4, 6),
    axis.title = element_text(size = 11),
    axis.title.x = element_text(margin = margin(5,5,15,5))  # Adiciona margem em baixo do eixo x
  )

Exemplo Real - Cancro

O conjunto de dados lung resulta de um estudo clínico conduzido pelo North Central Cancer Treatment Group (NCCTG, EUA), cujo objetivo foi analisar a sobrevivência de pacientes com cancro de pulmão avançado. O problema central consistiu em avaliar o tempo até ao óbito e identificar fatores clínicos e demográficos que influenciam o risco de morte. O estudo envolveu 228 pacientes, acompanhados ao longo do tempo, com presença de censura à direita. Nele encontramos 10 variáveis, incluindo variáveis de sobrevivência, demográficas e clínicas. A seguir descrevem-se as variáveis, a sua natureza e respetiva codificação.

data(cancer, package = "survival")

paged_table(lung) # Visualizar a Base de dados

Recodificar algumas variáveis (Sexo e Status)

lung = 
  lung %>%
  mutate (
    status = recode(status, "1" = 0, "2" = 1),
    
    sex = recode(sex, "1" = "Masculino", "2" = "Feminino"),
  )

Kaplan-Meier (Simples)

E_KM_4 = survfit(Surv(time, status)~1, data = lung);  E_KM_4;    summary(E_KM_4)    
## Call: survfit(formula = Surv(time, status) ~ 1, data = lung)
## 
##        n events median 0.95LCL 0.95UCL
## [1,] 228    165    310     285     363
## Call: survfit(formula = Surv(time, status) ~ 1, data = lung)
## 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##     5    228       1   0.9956 0.00438       0.9871        1.000
##    11    227       3   0.9825 0.00869       0.9656        1.000
##    12    224       1   0.9781 0.00970       0.9592        0.997
##    13    223       2   0.9693 0.01142       0.9472        0.992
##    15    221       1   0.9649 0.01219       0.9413        0.989
##    26    220       1   0.9605 0.01290       0.9356        0.986
##    30    219       1   0.9561 0.01356       0.9299        0.983
##    31    218       1   0.9518 0.01419       0.9243        0.980
##    53    217       2   0.9430 0.01536       0.9134        0.974
##    54    215       1   0.9386 0.01590       0.9079        0.970
##    59    214       1   0.9342 0.01642       0.9026        0.967
##    60    213       2   0.9254 0.01740       0.8920        0.960
##    61    211       1   0.9211 0.01786       0.8867        0.957
##    62    210       1   0.9167 0.01830       0.8815        0.953
##    65    209       2   0.9079 0.01915       0.8711        0.946
##    71    207       1   0.9035 0.01955       0.8660        0.943
##    79    206       1   0.8991 0.01995       0.8609        0.939
##    81    205       2   0.8904 0.02069       0.8507        0.932
##    88    203       2   0.8816 0.02140       0.8406        0.925
##    92    201       1   0.8772 0.02174       0.8356        0.921
##    93    199       1   0.8728 0.02207       0.8306        0.917
##    95    198       2   0.8640 0.02271       0.8206        0.910
##   105    196       1   0.8596 0.02302       0.8156        0.906
##   107    194       2   0.8507 0.02362       0.8056        0.898
##   110    192       1   0.8463 0.02391       0.8007        0.894
##   116    191       1   0.8418 0.02419       0.7957        0.891
##   118    190       1   0.8374 0.02446       0.7908        0.887
##   122    189       1   0.8330 0.02473       0.7859        0.883
##   131    188       1   0.8285 0.02500       0.7810        0.879
##   132    187       2   0.8197 0.02550       0.7712        0.871
##   135    185       1   0.8153 0.02575       0.7663        0.867
##   142    184       1   0.8108 0.02598       0.7615        0.863
##   144    183       1   0.8064 0.02622       0.7566        0.859
##   145    182       2   0.7975 0.02667       0.7469        0.852
##   147    180       1   0.7931 0.02688       0.7421        0.848
##   153    179       1   0.7887 0.02710       0.7373        0.844
##   156    178       2   0.7798 0.02751       0.7277        0.836
##   163    176       3   0.7665 0.02809       0.7134        0.824
##   166    173       2   0.7577 0.02845       0.7039        0.816
##   167    171       1   0.7532 0.02863       0.6991        0.811
##   170    170       1   0.7488 0.02880       0.6944        0.807
##   175    167       1   0.7443 0.02898       0.6896        0.803
##   176    165       1   0.7398 0.02915       0.6848        0.799
##   177    164       1   0.7353 0.02932       0.6800        0.795
##   179    162       2   0.7262 0.02965       0.6704        0.787
##   180    160       1   0.7217 0.02981       0.6655        0.783
##   181    159       2   0.7126 0.03012       0.6559        0.774
##   182    157       1   0.7081 0.03027       0.6511        0.770
##   183    156       1   0.7035 0.03041       0.6464        0.766
##   186    154       1   0.6989 0.03056       0.6416        0.761
##   189    152       1   0.6943 0.03070       0.6367        0.757
##   194    149       1   0.6897 0.03085       0.6318        0.753
##   197    147       1   0.6850 0.03099       0.6269        0.749
##   199    145       1   0.6803 0.03113       0.6219        0.744
##   201    144       2   0.6708 0.03141       0.6120        0.735
##   202    142       1   0.6661 0.03154       0.6071        0.731
##   207    139       1   0.6613 0.03168       0.6020        0.726
##   208    138       1   0.6565 0.03181       0.5970        0.722
##   210    137       1   0.6517 0.03194       0.5920        0.717
##   212    135       1   0.6469 0.03206       0.5870        0.713
##   218    134       1   0.6421 0.03218       0.5820        0.708
##   222    132       1   0.6372 0.03231       0.5769        0.704
##   223    130       1   0.6323 0.03243       0.5718        0.699
##   226    126       1   0.6273 0.03256       0.5666        0.694
##   229    125       1   0.6223 0.03268       0.5614        0.690
##   230    124       1   0.6172 0.03280       0.5562        0.685
##   239    121       2   0.6070 0.03304       0.5456        0.675
##   245    117       1   0.6019 0.03316       0.5402        0.670
##   246    116       1   0.5967 0.03328       0.5349        0.666
##   267    112       1   0.5913 0.03341       0.5294        0.661
##   268    111       1   0.5860 0.03353       0.5239        0.656
##   269    110       1   0.5807 0.03364       0.5184        0.651
##   270    108       1   0.5753 0.03376       0.5128        0.645
##   283    104       1   0.5698 0.03388       0.5071        0.640
##   284    103       1   0.5642 0.03400       0.5014        0.635
##   285    101       2   0.5531 0.03424       0.4899        0.624
##   286     99       1   0.5475 0.03434       0.4841        0.619
##   288     98       1   0.5419 0.03444       0.4784        0.614
##   291     97       1   0.5363 0.03454       0.4727        0.608
##   293     94       1   0.5306 0.03464       0.4669        0.603
##   301     91       1   0.5248 0.03475       0.4609        0.597
##   303     89       1   0.5189 0.03485       0.4549        0.592
##   305     87       1   0.5129 0.03496       0.4488        0.586
##   306     86       1   0.5070 0.03506       0.4427        0.581
##   310     85       2   0.4950 0.03523       0.4306        0.569
##   320     82       1   0.4890 0.03532       0.4244        0.563
##   329     81       1   0.4830 0.03539       0.4183        0.558
##   337     79       1   0.4768 0.03547       0.4121        0.552
##   340     78       1   0.4707 0.03554       0.4060        0.546
##   345     77       1   0.4646 0.03560       0.3998        0.540
##   348     76       1   0.4585 0.03565       0.3937        0.534
##   350     75       1   0.4524 0.03569       0.3876        0.528
##   351     74       1   0.4463 0.03573       0.3815        0.522
##   353     73       2   0.4340 0.03578       0.3693        0.510
##   361     70       1   0.4278 0.03581       0.3631        0.504
##   363     69       2   0.4154 0.03583       0.3508        0.492
##   364     67       1   0.4092 0.03582       0.3447        0.486
##   371     65       2   0.3966 0.03581       0.3323        0.473
##   387     60       1   0.3900 0.03582       0.3258        0.467
##   390     59       1   0.3834 0.03582       0.3193        0.460
##   394     58       1   0.3768 0.03580       0.3128        0.454
##   426     55       1   0.3700 0.03580       0.3060        0.447
##   428     54       1   0.3631 0.03579       0.2993        0.440
##   429     53       1   0.3563 0.03576       0.2926        0.434
##   433     52       1   0.3494 0.03573       0.2860        0.427
##   442     51       1   0.3426 0.03568       0.2793        0.420
##   444     50       1   0.3357 0.03561       0.2727        0.413
##   450     48       1   0.3287 0.03555       0.2659        0.406
##   455     47       1   0.3217 0.03548       0.2592        0.399
##   457     46       1   0.3147 0.03539       0.2525        0.392
##   460     44       1   0.3076 0.03530       0.2456        0.385
##   473     43       1   0.3004 0.03520       0.2388        0.378
##   477     42       1   0.2933 0.03508       0.2320        0.371
##   519     39       1   0.2857 0.03498       0.2248        0.363
##   520     38       1   0.2782 0.03485       0.2177        0.356
##   524     37       2   0.2632 0.03455       0.2035        0.340
##   533     34       1   0.2554 0.03439       0.1962        0.333
##   550     32       1   0.2475 0.03423       0.1887        0.325
##   558     30       1   0.2392 0.03407       0.1810        0.316
##   567     28       1   0.2307 0.03391       0.1729        0.308
##   574     27       1   0.2221 0.03371       0.1650        0.299
##   583     26       1   0.2136 0.03348       0.1571        0.290
##   613     24       1   0.2047 0.03325       0.1489        0.281
##   624     23       1   0.1958 0.03297       0.1407        0.272
##   641     22       1   0.1869 0.03265       0.1327        0.263
##   643     21       1   0.1780 0.03229       0.1247        0.254
##   654     20       1   0.1691 0.03188       0.1169        0.245
##   655     19       1   0.1602 0.03142       0.1091        0.235
##   687     18       1   0.1513 0.03090       0.1014        0.226
##   689     17       1   0.1424 0.03034       0.0938        0.216
##   705     16       1   0.1335 0.02972       0.0863        0.207
##   707     15       1   0.1246 0.02904       0.0789        0.197
##   728     14       1   0.1157 0.02830       0.0716        0.187
##   731     13       1   0.1068 0.02749       0.0645        0.177
##   735     12       1   0.0979 0.02660       0.0575        0.167
##   765     10       1   0.0881 0.02568       0.0498        0.156
##   791      9       1   0.0783 0.02462       0.0423        0.145
##   814      7       1   0.0671 0.02351       0.0338        0.133
##   883      4       1   0.0503 0.02285       0.0207        0.123
plot(E_KM_4, conf.int = F, mark.time = T, xlab = "Dias", ylab = "Sobrevivências",
     main = "Estimador ede Kaplan-Meier")

survfit(Surv(time, status)~1, data = lung) %>%
  ggsurvfit() +
  labs(
    x = "Dias",
    y = "probabilidade de Sobrevivência"
  )

Adicionando o intevalo de confiança

survfit(Surv(time, status)~1, data = lung) %>%
  ggsurvfit() +
  labs(
    x = "Dias",
    y = "probabilidade de Sobrevivência"
  ) +
  add_confidence_interval()

Adicionando tabela com o número de observações em risco

survfit(Surv(time, status)~1, data = lung) %>%
  ggsurvfit() +
  labs(
    x = "Dias",
    y = "probabilidade de Sobrevivência"
  ) +
  add_confidence_interval() +
  add_risktable()

Estimando a probabilidade de sobreviver até um certo tempo

summary(survfit(Surv(time, status)~1, data = lung), times = 200)
## Call: survfit(formula = Surv(time, status) ~ 1, data = lung)
## 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##   200    144      72     0.68  0.0311        0.622        0.744

Adicionando tabela de estimativas de probabilidades até um certo tempo

survfit(Surv(time, status)~1, data = lung) %>%
  tbl_survfit(                                 # do pacote  - gtsummary
    times = 200,
    label_header = "** Sobrevivência até 1 Ano - I.C 95% **"
  )
Characteristic ** Sobrevivência até 1 Ano - I.C 95% **
Overall 68% (62%, 74%)

Adicionando o tempo mediado de sobrevivência

survfit(Surv(time, status)~1, data = lung) %>%
  ggsurvfit() +
  labs(
    x = "Dias",
    y = "probabilidade de Sobrevivência"
  ) +
  add_confidence_interval() +
  add_risktable() +
  add_quantile()

O que aconteceria com o tempo mediano se excluíssimos as censuras

lung2 = 
  lung %>%
  
  filter (status == 1) %>%
  
  summarise( median_surv = median(time))

lung2 # Visualizando a alteração
##   median_surv
## 1         226

Isso faz com que subestimamos a estimativa do tempo mediano de sobrevivência.

Kaplan-Meier (Comparação)

E_KM_5 = survival::survfit(Surv(time, status)~sex, data = lung);  E_KM_5;    summary(E_KM_5)
## Call: survfit(formula = Surv(time, status) ~ sex, data = lung)
## 
##                 n events median 0.95LCL 0.95UCL
## sex=Feminino   90     53    426     348     550
## sex=Masculino 138    112    270     212     310
## Call: survfit(formula = Surv(time, status) ~ sex, data = lung)
## 
##                 sex=Feminino 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##     5     90       1   0.9889  0.0110       0.9675        1.000
##    60     89       1   0.9778  0.0155       0.9478        1.000
##    61     88       1   0.9667  0.0189       0.9303        1.000
##    62     87       1   0.9556  0.0217       0.9139        0.999
##    79     86       1   0.9444  0.0241       0.8983        0.993
##    81     85       1   0.9333  0.0263       0.8832        0.986
##    95     83       1   0.9221  0.0283       0.8683        0.979
##   107     81       1   0.9107  0.0301       0.8535        0.972
##   122     80       1   0.8993  0.0318       0.8390        0.964
##   145     79       2   0.8766  0.0349       0.8108        0.948
##   153     77       1   0.8652  0.0362       0.7970        0.939
##   166     76       1   0.8538  0.0375       0.7834        0.931
##   167     75       1   0.8424  0.0387       0.7699        0.922
##   182     71       1   0.8305  0.0399       0.7559        0.913
##   186     70       1   0.8187  0.0411       0.7420        0.903
##   194     68       1   0.8066  0.0422       0.7280        0.894
##   199     67       1   0.7946  0.0432       0.7142        0.884
##   201     66       2   0.7705  0.0452       0.6869        0.864
##   208     62       1   0.7581  0.0461       0.6729        0.854
##   226     59       1   0.7452  0.0471       0.6584        0.843
##   239     57       1   0.7322  0.0480       0.6438        0.833
##   245     54       1   0.7186  0.0490       0.6287        0.821
##   268     51       1   0.7045  0.0501       0.6129        0.810
##   285     47       1   0.6895  0.0512       0.5962        0.798
##   293     45       1   0.6742  0.0523       0.5791        0.785
##   305     43       1   0.6585  0.0534       0.5618        0.772
##   310     42       1   0.6428  0.0544       0.5447        0.759
##   340     39       1   0.6264  0.0554       0.5267        0.745
##   345     38       1   0.6099  0.0563       0.5089        0.731
##   348     37       1   0.5934  0.0572       0.4913        0.717
##   350     36       1   0.5769  0.0579       0.4739        0.702
##   351     35       1   0.5604  0.0586       0.4566        0.688
##   361     33       1   0.5434  0.0592       0.4390        0.673
##   363     32       1   0.5265  0.0597       0.4215        0.658
##   371     30       1   0.5089  0.0603       0.4035        0.642
##   426     26       1   0.4893  0.0610       0.3832        0.625
##   433     25       1   0.4698  0.0617       0.3632        0.608
##   444     24       1   0.4502  0.0621       0.3435        0.590
##   450     23       1   0.4306  0.0624       0.3241        0.572
##   473     22       1   0.4110  0.0626       0.3050        0.554
##   520     19       1   0.3894  0.0629       0.2837        0.534
##   524     18       1   0.3678  0.0630       0.2628        0.515
##   550     15       1   0.3433  0.0634       0.2390        0.493
##   641     11       1   0.3121  0.0649       0.2076        0.469
##   654     10       1   0.2808  0.0655       0.1778        0.443
##   687      9       1   0.2496  0.0652       0.1496        0.417
##   705      8       1   0.2184  0.0641       0.1229        0.388
##   728      7       1   0.1872  0.0621       0.0978        0.359
##   731      6       1   0.1560  0.0590       0.0743        0.328
##   735      5       1   0.1248  0.0549       0.0527        0.295
##   765      3       1   0.0832  0.0499       0.0257        0.270
## 
##                 sex=Masculino 
##  time n.risk n.event survival std.err lower 95% CI upper 95% CI
##    11    138       3   0.9783  0.0124       0.9542        1.000
##    12    135       1   0.9710  0.0143       0.9434        0.999
##    13    134       2   0.9565  0.0174       0.9231        0.991
##    15    132       1   0.9493  0.0187       0.9134        0.987
##    26    131       1   0.9420  0.0199       0.9038        0.982
##    30    130       1   0.9348  0.0210       0.8945        0.977
##    31    129       1   0.9275  0.0221       0.8853        0.972
##    53    128       2   0.9130  0.0240       0.8672        0.961
##    54    126       1   0.9058  0.0249       0.8583        0.956
##    59    125       1   0.8986  0.0257       0.8496        0.950
##    60    124       1   0.8913  0.0265       0.8409        0.945
##    65    123       2   0.8768  0.0280       0.8237        0.933
##    71    121       1   0.8696  0.0287       0.8152        0.928
##    81    120       1   0.8623  0.0293       0.8067        0.922
##    88    119       2   0.8478  0.0306       0.7900        0.910
##    92    117       1   0.8406  0.0312       0.7817        0.904
##    93    116       1   0.8333  0.0317       0.7734        0.898
##    95    115       1   0.8261  0.0323       0.7652        0.892
##   105    114       1   0.8188  0.0328       0.7570        0.886
##   107    113       1   0.8116  0.0333       0.7489        0.880
##   110    112       1   0.8043  0.0338       0.7408        0.873
##   116    111       1   0.7971  0.0342       0.7328        0.867
##   118    110       1   0.7899  0.0347       0.7247        0.861
##   131    109       1   0.7826  0.0351       0.7167        0.855
##   132    108       2   0.7681  0.0359       0.7008        0.842
##   135    106       1   0.7609  0.0363       0.6929        0.835
##   142    105       1   0.7536  0.0367       0.6851        0.829
##   144    104       1   0.7464  0.0370       0.6772        0.823
##   147    103       1   0.7391  0.0374       0.6694        0.816
##   156    102       2   0.7246  0.0380       0.6538        0.803
##   163    100       3   0.7029  0.0389       0.6306        0.783
##   166     97       1   0.6957  0.0392       0.6230        0.777
##   170     96       1   0.6884  0.0394       0.6153        0.770
##   175     94       1   0.6811  0.0397       0.6076        0.763
##   176     93       1   0.6738  0.0399       0.5999        0.757
##   177     92       1   0.6664  0.0402       0.5922        0.750
##   179     91       2   0.6518  0.0406       0.5769        0.736
##   180     89       1   0.6445  0.0408       0.5693        0.730
##   181     88       2   0.6298  0.0412       0.5541        0.716
##   183     86       1   0.6225  0.0413       0.5466        0.709
##   189     83       1   0.6150  0.0415       0.5388        0.702
##   197     80       1   0.6073  0.0417       0.5309        0.695
##   202     78       1   0.5995  0.0419       0.5228        0.687
##   207     77       1   0.5917  0.0420       0.5148        0.680
##   210     76       1   0.5839  0.0422       0.5068        0.673
##   212     75       1   0.5762  0.0424       0.4988        0.665
##   218     74       1   0.5684  0.0425       0.4909        0.658
##   222     72       1   0.5605  0.0426       0.4829        0.651
##   223     70       1   0.5525  0.0428       0.4747        0.643
##   229     67       1   0.5442  0.0429       0.4663        0.635
##   230     66       1   0.5360  0.0431       0.4579        0.627
##   239     64       1   0.5276  0.0432       0.4494        0.619
##   246     63       1   0.5192  0.0433       0.4409        0.611
##   267     61       1   0.5107  0.0434       0.4323        0.603
##   269     60       1   0.5022  0.0435       0.4238        0.595
##   270     59       1   0.4937  0.0436       0.4152        0.587
##   283     57       1   0.4850  0.0437       0.4065        0.579
##   284     56       1   0.4764  0.0438       0.3979        0.570
##   285     54       1   0.4676  0.0438       0.3891        0.562
##   286     53       1   0.4587  0.0439       0.3803        0.553
##   288     52       1   0.4499  0.0439       0.3716        0.545
##   291     51       1   0.4411  0.0439       0.3629        0.536
##   301     48       1   0.4319  0.0440       0.3538        0.527
##   303     46       1   0.4225  0.0440       0.3445        0.518
##   306     44       1   0.4129  0.0440       0.3350        0.509
##   310     43       1   0.4033  0.0441       0.3256        0.500
##   320     42       1   0.3937  0.0440       0.3162        0.490
##   329     41       1   0.3841  0.0440       0.3069        0.481
##   337     40       1   0.3745  0.0439       0.2976        0.471
##   353     39       2   0.3553  0.0437       0.2791        0.452
##   363     37       1   0.3457  0.0436       0.2700        0.443
##   364     36       1   0.3361  0.0434       0.2609        0.433
##   371     35       1   0.3265  0.0432       0.2519        0.423
##   387     34       1   0.3169  0.0430       0.2429        0.413
##   390     33       1   0.3073  0.0428       0.2339        0.404
##   394     32       1   0.2977  0.0425       0.2250        0.394
##   428     29       1   0.2874  0.0423       0.2155        0.383
##   429     28       1   0.2771  0.0420       0.2060        0.373
##   442     27       1   0.2669  0.0417       0.1965        0.362
##   455     25       1   0.2562  0.0413       0.1868        0.351
##   457     24       1   0.2455  0.0410       0.1770        0.341
##   460     22       1   0.2344  0.0406       0.1669        0.329
##   477     21       1   0.2232  0.0402       0.1569        0.318
##   519     20       1   0.2121  0.0397       0.1469        0.306
##   524     19       1   0.2009  0.0391       0.1371        0.294
##   533     18       1   0.1897  0.0385       0.1275        0.282
##   558     17       1   0.1786  0.0378       0.1179        0.270
##   567     16       1   0.1674  0.0371       0.1085        0.258
##   574     15       1   0.1562  0.0362       0.0992        0.246
##   583     14       1   0.1451  0.0353       0.0900        0.234
##   613     13       1   0.1339  0.0343       0.0810        0.221
##   624     12       1   0.1228  0.0332       0.0722        0.209
##   643     11       1   0.1116  0.0320       0.0636        0.196
##   655     10       1   0.1004  0.0307       0.0552        0.183
##   689      9       1   0.0893  0.0293       0.0470        0.170
##   707      8       1   0.0781  0.0276       0.0390        0.156
##   791      7       1   0.0670  0.0259       0.0314        0.143
##   814      5       1   0.0536  0.0239       0.0223        0.128
##   883      3       1   0.0357  0.0216       0.0109        0.117

Adicionando tabela com o número de observações em risco

survfit(Surv(time, status)~sex, data = lung) %>%
  ggsurvfit() +
  labs(
    x = "Dias",
    y = "probabilidade de Sobrevivência"
  ) +
  add_confidence_interval() +
  add_risktable()

Testes de Comparação

Realizando os Testes de Comparações (Exemplo de Diabete)

survdiff(Surv(time, status) ~ trt, data = diabetic)
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic)
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197      101     71.8      11.9      22.2
## trt=1 197       54     83.2      10.3      22.2
## 
##  Chisq= 22.2  on 1 degrees of freedom, p= 2e-06
survdiff(Surv(time, status) ~ trt, data = diabetic) # Log-Rank
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic)
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197      101     71.8      11.9      22.2
## trt=1 197       54     83.2      10.3      22.2
## 
##  Chisq= 22.2  on 1 degrees of freedom, p= 2e-06
survdiff(Surv(time, status) ~ trt, data = diabetic, rho = 1) # Wilcoxon (Breslow) ← Peto-Prent. Aproximado
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic, 
##     rho = 1)
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197     80.3     57.6      8.95      20.7
## trt=1 197     43.1     65.8      7.84      20.7
## 
##  Chisq= 20.7  on 1 degrees of freedom, p= 6e-06
survdiff(Surv(time, status) ~ trt, data = diabetic, rho = 0.5) # Tarone-Ware
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic, 
##     rho = 0.5)
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197     89.7     64.1     10.28      21.5
## trt=1 197     48.1     73.7      8.93      21.5
## 
##  Chisq= 21.5  on 1 degrees of freedom, p= 3e-06
survdiff(Surv(time, status) ~ trt, data = diabetic, rho = c(0,1)) # Harrington-Fleming
## Call:
## survdiff(formula = Surv(time, status) ~ trt, data = diabetic, 
##     rho = c(0, 1))
## 
##         N Observed Expected (O-E)^2/E (O-E)^2/V
## trt=0 197      101     71.8      11.9      22.2
## trt=1 197       54     83.2      10.3      22.2
## 
##  Chisq= 22.2  on 1 degrees of freedom, p= 2e-06

Realizando os Testes de Comparações (Exemplo de Cancro)

survdiff(Surv(time, status) ~ sex, data = lung) # Log-Rank  
## Call:
## survdiff(formula = Surv(time, status) ~ sex, data = lung)
## 
##                 N Observed Expected (O-E)^2/E (O-E)^2/V
## sex=Feminino   90       53     73.4      5.68      10.3
## sex=Masculino 138      112     91.6      4.55      10.3
## 
##  Chisq= 10.3  on 1 degrees of freedom, p= 0.001
survdiff(Surv(time, status) ~ sex, data = lung, rho = 1) # Wilcoxon (Breslow) ← Peto-Prent. Aproximado  
## Call:
## survdiff(formula = Surv(time, status) ~ sex, data = lung, rho = 1)
## 
##                 N Observed Expected (O-E)^2/E (O-E)^2/V
## sex=Feminino   90     28.7     43.5      5.04      12.7
## sex=Masculino 138     70.4     55.6      3.95      12.7
## 
##  Chisq= 12.7  on 1 degrees of freedom, p= 4e-04
survdiff(Surv(time, status) ~ sex, data = lung, rho = 0.5) # Tarone-Ware  
## Call:
## survdiff(formula = Surv(time, status) ~ sex, data = lung, rho = 0.5)
## 
##                 N Observed Expected (O-E)^2/E (O-E)^2/V
## sex=Feminino   90     37.7     54.9      5.41      12.3
## sex=Masculino 138     86.4     69.1      4.30      12.3
## 
##  Chisq= 12.3  on 1 degrees of freedom, p= 5e-04
survdiff(Surv(time, status) ~ sex, data = lung, rho = c(0,1)) # Harrington-Fleming
## Call:
## survdiff(formula = Surv(time, status) ~ sex, data = lung, rho = c(0, 
##     1))
## 
##                 N Observed Expected (O-E)^2/E (O-E)^2/V
## sex=Feminino   90       53     73.4      5.68      10.3
## sex=Masculino 138      112     91.6      4.55      10.3
## 
##  Chisq= 10.3  on 1 degrees of freedom, p= 0.001