Indlæser pakker

Loading required package: Hmisc
Loading required package: lattice
Loading required package: Formula

Attaching package: 'Hmisc'
The following objects are masked from 'package:base':

    format.pval, round.POSIXt, trunc.POSIXt, units
Loading required package: SparseM

Attaching package: 'SparseM'
The following object is masked from 'package:base':

    backsolve

Data Management og overblik

#Variabelforklaring:

    #osm = survival time
    #survival = 1
    #death = 0

data<- read.dta(file.path("C:/Users/Vision/Desktop/STATISTIK/BIOSTATISTIK2/Nodaold.dta"))
data <-data[,c(1,2,3)] # Sletter unødvendige kolonner
head(data, n=10)  # viser første 10 rækker af det tilpassede datasæt
   survive trt_arm       osm
1        1       1 13.568789
2        1       1 11.696099
3        1       1 12.517454
4        1       1 30.652977
5        1       1  2.726899
6        1       1 25.494867
7        1       1 13.305955
8        1       1 16.887064
9        1       1 10.940452
10       1       1  8.180698
data$survive <- as.numeric(data$survive)
data$osm<- as.numeric(data$osm)  

OPG. 1-3) Kaplan Meier for each treatment with confidence intervals

# laver survival objekt:
survobj <- with(data, Surv(osm, survive == 0))
head(survobj)
[1] 13.568789+ 11.696099+ 12.517454+ 30.652977+  2.726899+ 25.494867+
#survobj <- as.numeric(data$survobj)  


survcompare<-survfit(Surv(data$osm, data$survive)~data$trt_arm, data=data)
summary(survcompare)
Call: survfit(formula = Surv(data$osm, data$survive) ~ data$trt_arm, 
    data = data)

                data$trt_arm=1 
   time n.risk n.event survival std.err lower 95% CI upper 95% CI
  0.559     77       1   0.9870  0.0129       0.9620        1.000
  2.136     76       1   0.9740  0.0181       0.9391        1.000
  2.267     75       2   0.9481  0.0253       0.8998        0.999
  2.727     73       1   0.9351  0.0281       0.8816        0.992
  4.534     72       1   0.9221  0.0305       0.8641        0.984
  4.862     71       1   0.9091  0.0328       0.8471        0.976
  4.961     70       1   0.8961  0.0348       0.8305        0.967
  5.092     69       1   0.8831  0.0366       0.8142        0.958
  5.914     68       1   0.8701  0.0383       0.7982        0.949
  6.538     67       1   0.8571  0.0399       0.7824        0.939
  7.129     66       1   0.8442  0.0413       0.7669        0.929
  7.852     65       1   0.8312  0.0427       0.7516        0.919
  8.016     64       1   0.8182  0.0440       0.7364        0.909
  8.181     63       1   0.8052  0.0451       0.7214        0.899
  8.411     62       1   0.7922  0.0462       0.7066        0.888
  8.444     61       1   0.7792  0.0473       0.6919        0.878
  9.133     60       1   0.7662  0.0482       0.6773        0.867
  9.199     59       1   0.7532  0.0491       0.6629        0.856
  9.725     58       1   0.7403  0.0500       0.6485        0.845
  9.758     57       1   0.7273  0.0508       0.6343        0.834
  9.922     56       2   0.7013  0.0522       0.6062        0.811
 10.021     54       1   0.6883  0.0528       0.5923        0.800
 10.086     53       1   0.6753  0.0534       0.5784        0.788
 10.119     52       1   0.6623  0.0539       0.5647        0.777
 10.875     51       1   0.6494  0.0544       0.5511        0.765
 10.940     50       1   0.6364  0.0548       0.5375        0.753
 10.973     49       1   0.6234  0.0552       0.5240        0.742
 11.400     48       1   0.6104  0.0556       0.5106        0.730
 11.696     47       1   0.5974  0.0559       0.4973        0.718
 11.795     46       1   0.5844  0.0562       0.4841        0.706
 12.057     45       1   0.5714  0.0564       0.4709        0.693
 12.452     44       1   0.5584  0.0566       0.4578        0.681
 12.485     43       1   0.5455  0.0567       0.4448        0.669
 12.517     42       2   0.5195  0.0569       0.4191        0.644
 12.550     40       1   0.5065  0.0570       0.4063        0.631
 12.813     39       1   0.4935  0.0570       0.3936        0.619
 13.010     38       1   0.4805  0.0569       0.3809        0.606
 13.306     37       1   0.4675  0.0569       0.3684        0.593
 13.503     36       1   0.4545  0.0567       0.3559        0.581
 13.536     35       1   0.4416  0.0566       0.3435        0.568
 13.569     34       1   0.4286  0.0564       0.3311        0.555
 13.700     33       1   0.4156  0.0562       0.3189        0.542
 15.113     32       1   0.4026  0.0559       0.3067        0.528
 15.244     31       1   0.3896  0.0556       0.2946        0.515
 15.606     30       1   0.3766  0.0552       0.2826        0.502
 15.639     29       1   0.3636  0.0548       0.2706        0.489
 15.803     28       1   0.3506  0.0544       0.2587        0.475
 16.526     27       1   0.3377  0.0539       0.2470        0.462
 16.559     26       1   0.3247  0.0534       0.2353        0.448
 16.887     25       1   0.3117  0.0528       0.2237        0.434
 17.183     24       1   0.2987  0.0522       0.2121        0.421
 17.281     23       1   0.2857  0.0515       0.2007        0.407
 17.906     22       1   0.2727  0.0508       0.1894        0.393
 18.366     21       1   0.2597  0.0500       0.1781        0.379
 19.154     20       2   0.2338  0.0482       0.1560        0.350
 19.680     18       1   0.2208  0.0473       0.1451        0.336
 22.735     17       1   0.2078  0.0462       0.1343        0.321
 23.589     16       1   0.1948  0.0451       0.1237        0.307
 25.495     15       1   0.1818  0.0440       0.1132        0.292
 26.283     14       1   0.1688  0.0427       0.1029        0.277
 27.368     13       1   0.1558  0.0413       0.0927        0.262
 29.996     12       1   0.1429  0.0399       0.0827        0.247
 30.653     11       1   0.1299  0.0383       0.0728        0.232
 34.201      8       1   0.1136  0.0368       0.0602        0.214
 37.651      7       1   0.0974  0.0349       0.0482        0.197
 56.378      1       1   0.0000     NaN           NA           NA

                data$trt_arm=2 
  time n.risk n.event survival std.err lower 95% CI upper 95% CI
  1.94     77       1   0.9870  0.0129      0.96205        1.000
  2.30     76       1   0.9740  0.0181      0.93914        1.000
  2.86     75       1   0.9610  0.0221      0.91878        1.000
  3.75     74       1   0.9481  0.0253      0.89976        0.999
  4.37     73       1   0.9351  0.0281      0.88162        0.992
  4.86     72       1   0.9221  0.0305      0.86411        0.984
  4.93     71       1   0.9091  0.0328      0.84710        0.976
  5.13     70       1   0.8961  0.0348      0.83048        0.967
  5.26     69       1   0.8831  0.0366      0.81419        0.958
  5.36     68       2   0.8571  0.0399      0.78244        0.939
  5.49     66       1   0.8442  0.0413      0.76691        0.929
  5.52     65       1   0.8312  0.0427      0.75157        0.919
  5.82     64       1   0.8182  0.0440      0.73641        0.909
  5.88     63       1   0.8052  0.0451      0.72142        0.899
  5.95     62       1   0.7922  0.0462      0.70658        0.888
  5.98     61       1   0.7792  0.0473      0.69187        0.878
  6.05     60       1   0.7662  0.0482      0.67730        0.867
  6.18     59       1   0.7532  0.0491      0.66285        0.856
  6.37     58       1   0.7403  0.0500      0.64852        0.845
  6.47     57       1   0.7273  0.0508      0.63430        0.834
  6.57     56       1   0.7143  0.0515      0.62019        0.823
  6.67     55       1   0.7013  0.0522      0.60617        0.811
  6.80     54       1   0.6883  0.0528      0.59226        0.800
  7.10     53       1   0.6753  0.0534      0.57843        0.788
  7.26     52       1   0.6623  0.0539      0.56470        0.777
  7.56     51       1   0.6494  0.0544      0.55106        0.765
  7.95     50       1   0.6364  0.0548      0.53750        0.753
  8.02     49       1   0.6234  0.0552      0.52402        0.742
  8.11     48       2   0.5974  0.0559      0.49732        0.718
  8.34     46       1   0.5844  0.0562      0.48408        0.706
  8.38     45       1   0.5714  0.0564      0.47093        0.693
  8.71     44       1   0.5584  0.0566      0.45785        0.681
  8.74     43       1   0.5455  0.0567      0.44484        0.669
  9.26     42       1   0.5325  0.0569      0.43191        0.656
  9.30     41       1   0.5195  0.0569      0.41906        0.644
  9.40     40       1   0.5065  0.0570      0.40628        0.631
  9.43     39       2   0.4805  0.0569      0.38094        0.606
  9.49     37       1   0.4675  0.0569      0.36838        0.593
  9.59     36       1   0.4545  0.0567      0.35589        0.581
  9.69     35       1   0.4416  0.0566      0.34348        0.568
  9.79     34       2   0.4156  0.0562      0.31888        0.542
 10.51     32       1   0.4026  0.0559      0.30670        0.528
 10.84     31       1   0.3896  0.0556      0.29459        0.515
 11.76     30       1   0.3766  0.0552      0.28256        0.502
 12.58     29       1   0.3636  0.0548      0.27061        0.489
 12.81     28       1   0.3506  0.0544      0.25874        0.475
 13.14     27       1   0.3377  0.0539      0.24696        0.462
 13.27     26       1   0.3247  0.0534      0.23526        0.448
 13.34     25       1   0.3117  0.0528      0.22365        0.434
 13.54     24       1   0.2987  0.0522      0.21213        0.421
 13.86     23       1   0.2857  0.0515      0.20070        0.407
 14.03     22       1   0.2727  0.0508      0.18938        0.393
 14.65     21       1   0.2597  0.0500      0.17815        0.379
 14.69     20       1   0.2468  0.0491      0.16702        0.365
 15.01     19       1   0.2338  0.0482      0.15601        0.350
 15.28     18       1   0.2208  0.0473      0.14512        0.336
 15.47     17       1   0.2078  0.0462      0.13435        0.321
 15.54     16       1   0.1948  0.0451      0.12370        0.307
 15.87     15       1   0.1818  0.0440      0.11320        0.292
 16.26     14       1   0.1688  0.0427      0.10285        0.277
 16.36     13       1   0.1558  0.0413      0.09267        0.262
 16.46     12       2   0.1299  0.0383      0.07285        0.232
 17.41     10       1   0.1169  0.0366      0.06326        0.216
 17.61      9       1   0.1039  0.0348      0.05392        0.200
 18.79      8       1   0.0909  0.0328      0.04486        0.184
 18.99      7       1   0.0779  0.0305      0.03614        0.168
 19.29      6       1   0.0649  0.0281      0.02782        0.152
 21.75      5       1   0.0519  0.0253      0.02001        0.135
 38.57      3       1   0.0346  0.0220      0.00997        0.120
plot(survcompare, conf.int = TRUE, col=c("blue", "red"), xlab = "Survival (Months)", ylab="Survival (proportion)")
legend(30,1, c("treat_arm 1", "treat_arm 2"), col=c("blue","red"), lwd=0.5)
title("Survival by treatment with 95% conf.intervals")

Her ses at usikkerhedden bliver stor og overlappende efter 20 måneder.

OPG 4 - Er der forskel på de to behandlinger?

##7 sample test
survdiff(Surv(data$osm, data$survive)~data$trt_arm, data=data)
Call:
survdiff(formula = Surv(data$osm, data$survive) ~ data$trt_arm, 
    data = data)

                N Observed Expected (O-E)^2/E (O-E)^2/V
data$trt_arm=1 77       70     87.7      3.56      9.41
data$trt_arm=2 77       74     56.3      5.54      9.41

 Chisq= 9.4  on 1 degrees of freedom, p= 0.00215 

Der er altså forskel på de 2 behandlingsarme

Med COX

coxph<-(coxph(Surv(data$osm, data$survive)~data$trt_arm, data=data))
coxph
Call:
coxph(formula = Surv(data$osm, data$survive) ~ data$trt_arm, 
    data = data)

              coef exp(coef) se(coef)    z      p
data$trt_arm 0.516     1.675    0.170 3.04 0.0024

Likelihood ratio test=9.19  on 1 df, p=0.00244
n= 154, number of events= 144 

Resulterer i stort set den samme P-værdi