data source: “ArMorr DBP DNA 12 23 2015.xlsx”

Matched Sample

matched on age (+/- 2 years), albumin (+/- 0.2 mg/dl), catheter status, and diabetes status

dat.group1 <- subset(dat2, group==1)
dat.group0 <- subset(dat2, group==0)

dat.match.id <- numeric(0)  
for(i in 1:nrow(dat.group1)){
  temp <- subset(dat.group0, catheter == dat.group1$catheter[i] & 
                   diabetes == dat.group1$diabetes[i] &
                   Age <= dat.group1$Age[i] + 1 &
                   Age >= dat.group1$Age[i] - 1 &
                   alb14 <= dat.group1$alb14[i] + .1 &
                   alb14 >= dat.group1$alb14[i] - .1
                   )
  if(nrow(temp) != 0){
    dat.match.id <- append(dat.match.id, c(dat.group1$MRN[i], temp$MRN))
  }
}
dat.match <- subset(dat2, MRN %in% unique(dat.match.id))

Baseline information: matched sample

##    Variable              DBP7.A           DBP7.AG.G P.Value
## 1       Age   65.2 + 13.5 (684)   64.2 + 13.6 (760)   0.142
## 2       Sex  398 / 684 (58.2 %)  392 / 760 (51.6 %)   0.014
## 3     Race2  594 / 684 (86.8 %)  291 / 760 (38.3 %)   <.001
## 4    Ethnic  101 / 684 (14.8 %)   95 / 760 (12.5 %)   0.239
## 5  diabetes  306 / 684 (44.7 %)  353 / 760 (46.4 %)   0.549
## 6  catheter  493 / 684 (72.1 %)  536 / 760 (70.5 %)   0.554
## 7       BMI    27.7 + 7.5 (683)    28.1 + 8.4 (760)   0.301
## 8     sbp14  140.7 + 21.9 (684)  145.0 + 22.8 (760)   <.001
## 9     dbp14   71.2 + 12.8 (684)   73.9 + 12.8 (760)   <.001
## 10     ca14     8.5 + 0.8 (680)     8.5 + 0.8 (755)   0.663
## 11     cr14     5.8 + 2.4 (661)     6.6 + 2.8 (746)   <.001
## 12    alk14   98.6 + 67.7 (641)   97.8 + 61.4 (713)   0.815
## 13    alb14     3.5 + 0.4 (684)     3.5 + 0.4 (760)    0.17
## 14    pth14 264.6 + 239.7 (533) 315.1 + 245.1 (585)   <.001
## 15   phos14     4.7 + 1.6 (681)     4.7 + 1.5 (752)   0.501
## 16    wbc14     9.0 + 3.2 (664)     8.5 + 3.0 (742)   0.003
## 17   ferr14 300.9 + 353.1 (641) 312.2 + 314.7 (709)   0.535
## 18   Ivvitd  449 / 684 (65.6 %)  559 / 760 (73.6 %)   0.001

Kaplan Meier Curve: matched sample

km.m <- survfit(Surv(fu, Death)~group, data=dat.match)
ggkmTable(km.m, ystratalabs=c("A", "AG/G"), timeby=50, main="DBP 7: A vs. AG/G")

Cox model: matched sample

cox.match.fit <- coxph(Surv(fu, Death)~group+Age+Race2+diabetes+pth14+
                         ca14+phos14+alb14+catheter+Ivvitd, dat.match)
summary(cox.match.fit)
## Call:
## coxph(formula = Surv(fu, Death) ~ group + Age + Race2 + diabetes + 
##     pth14 + ca14 + phos14 + alb14 + catheter + Ivvitd, data = dat.match)
## 
##   n= 1109, number of events= 154 
##    (335 observations deleted due to missingness)
## 
##                 coef  exp(coef)   se(coef)      z Pr(>|z|)    
## group0    -0.3755543  0.6869084  0.1859876 -2.019   0.0435 *  
## Age        0.0482319  1.0494140  0.0075437  6.394 1.62e-10 ***
## Race2NW    0.0753797  1.0782935  0.2012293  0.375   0.7080    
## diabetes0  0.0490441  1.0502667  0.1690487  0.290   0.7717    
## pth14      0.0006003  1.0006005  0.0003099  1.937   0.0528 .  
## ca14       0.2564089  1.2922810  0.1152583  2.225   0.0261 *  
## phos14     0.0673271  1.0696453  0.0574055  1.173   0.2409    
## alb14     -1.1051179  0.3311718  0.2316147 -4.771 1.83e-06 ***
## catheter0 -0.2248141  0.7986647  0.1876544 -1.198   0.2309    
## Ivvitd0   -0.1561226  0.8554543  0.1983388 -0.787   0.4312    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##           exp(coef) exp(-coef) lower .95 upper .95
## group0       0.6869     1.4558    0.4771    0.9890
## Age          1.0494     0.9529    1.0340    1.0650
## Race2NW      1.0783     0.9274    0.7269    1.5996
## diabetes0    1.0503     0.9521    0.7541    1.4628
## pth14        1.0006     0.9994    1.0000    1.0012
## ca14         1.2923     0.7738    1.0310    1.6198
## phos14       1.0696     0.9349    0.9558    1.1970
## alb14        0.3312     3.0196    0.2103    0.5214
## catheter0    0.7987     1.2521    0.5529    1.1537
## Ivvitd0      0.8555     1.1690    0.5799    1.2619
## 
## Concordance= 0.692  (se = 0.023 )
## Rsquare= 0.064   (max possible= 0.854 )
## Likelihood ratio test= 73.28  on 10 df,   p=1.025e-11
## Wald test            = 67.4  on 10 df,   p=1.402e-10
## Score (logrank) test = 69.61  on 10 df,   p=5.275e-11

Logistic model: matched sample

logit.match.fit <- glm(Death~group+Age+Race2+diabetes+pth14+ca14+phos14+alb14+catheter+Ivvitd, 
                       dat.match, family="binomial")
summary(logit.match.fit)
## 
## Call:
## glm(formula = Death ~ group + Age + Race2 + diabetes + pth14 + 
##     ca14 + phos14 + alb14 + catheter + Ivvitd, family = "binomial", 
##     data = dat.match)
## 
## Deviance Residuals: 
##     Min       1Q   Median       3Q      Max  
## -1.2630  -0.5945  -0.4448  -0.3109   2.6766  
## 
## Coefficients:
##               Estimate Std. Error z value Pr(>|z|)    
## (Intercept) -3.9827697  1.2780070  -3.116  0.00183 ** 
## group0      -0.4261659  0.2060856  -2.068  0.03865 *  
## Age          0.0534824  0.0083848   6.378 1.79e-10 ***
## Race2NW      0.1091614  0.2229966   0.490  0.62447    
## diabetes0    0.0422514  0.1878069   0.225  0.82200    
## pth14        0.0007587  0.0003848   1.972  0.04864 *  
## ca14         0.2763062  0.1285721   2.149  0.03163 *  
## phos14       0.0694453  0.0626583   1.108  0.26773    
## alb14       -1.1880181  0.2589360  -4.588 4.47e-06 ***
## catheter0   -0.2322685  0.2063424  -1.126  0.26032    
## Ivvitd0     -0.1382625  0.2220417  -0.623  0.53349    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 893.62  on 1108  degrees of freedom
## Residual deviance: 821.00  on 1098  degrees of freedom
##   (335 observations deleted due to missingness)
## AIC: 843
## 
## Number of Fisher Scoring iterations: 5