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, dbp(+/-5), sbp(+/-5).

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$Age[i] + 2 &
                   Age >= dat.group1$Age[i] - 2 &
                   alb14 <= dat.group1$alb14[i] + .2 &
                   alb14 >= dat.group1$alb14[i] - .2 &
                   #Sex == dat.group1$Sex[i] &
                   sbp14 <= dat.group1$sbp14[i] + 5 &
                   sbp14 >= dat.group1$sbp14[i] - 5 &
                   dbp14 <= dat.group1$dbp14[i] + 5 &
                   dbp14 >= dat.group1$dbp14[i] - 5               
                   )
  if(nrow(temp) != 0){
    dat.match.id <- append(dat.match.id, c(dat.group1$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   66.5 + 13.1 (275)   65.4 + 13.4 (285)   0.328
## 2       Sex  163 / 275 (59.3 %)  147 / 285 (51.6 %)   0.081
## 3     Race2  243 / 275 (88.4 %)  116 / 285 (40.7 %)   <.001
## 4    Ethnic   40 / 275 (14.5 %)   37 / 285 (13.0 %)   0.679
## 5  diabetes  129 / 275 (46.9 %)  132 / 285 (46.3 %)   0.955
## 6  catheter  195 / 275 (70.9 %)  202 / 285 (70.9 %)   >.999
## 7       BMI    28.3 + 7.5 (275)    28.3 + 7.3 (285)   0.987
## 8     sbp14  139.2 + 15.9 (275)  140.2 + 15.7 (285)   0.463
## 9     dbp14    70.4 + 9.4 (275)    70.7 + 9.1 (285)   0.674
## 10     ca14     8.6 + 0.8 (273)     8.5 + 0.8 (284)   0.226
## 11     cr14     5.7 + 2.1 (268)     6.5 + 2.6 (280)   <.001
## 12    alk14   90.9 + 55.6 (249)   97.5 + 50.4 (268)   0.155
## 13    alb14     3.6 + 0.4 (275)     3.6 + 0.3 (285)   0.711
## 14    pth14 254.3 + 244.1 (217) 322.0 + 236.0 (217)   0.003
## 15   phos14     4.7 + 1.6 (274)     4.6 + 1.4 (284)   0.342
## 16    wbc14     8.5 + 2.8 (265)     8.5 + 2.9 (277)   0.941
## 17   ferr14 274.6 + 341.1 (257) 292.7 + 310.3 (267)   0.527
## 18   Ivvitd  181 / 275 (65.8 %)  218 / 285 (76.5 %)   0.007

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= 431, number of events= 50 
##    (129 observations deleted due to missingness)
## 
##                 coef  exp(coef)   se(coef)      z Pr(>|z|)   
## group0    -0.1938943  0.8237450  0.3247054 -0.597  0.55041   
## Age        0.0402860  1.0411085  0.0135641  2.970  0.00298 **
## Race2NW    0.3697035  1.4473055  0.3557284  1.039  0.29867   
## diabetes0  0.2049118  1.2274169  0.2996748  0.684  0.49411   
## pth14     -0.0007699  0.9992304  0.0008223 -0.936  0.34908   
## ca14       0.1724692  1.1882353  0.2020738  0.853  0.39338   
## phos14    -0.0358190  0.9648149  0.1082293 -0.331  0.74068   
## alb14     -0.3225492  0.7243003  0.4281990 -0.753  0.45129   
## catheter0 -0.3771625  0.6858047  0.3289984 -1.146  0.25163   
## Ivvitd0   -0.3390295  0.7124614  0.3517461 -0.964  0.33512   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##           exp(coef) exp(-coef) lower .95 upper .95
## group0       0.8237     1.2140    0.4359     1.557
## Age          1.0411     0.9605    1.0138     1.069
## Race2NW      1.4473     0.6909    0.7207     2.906
## diabetes0    1.2274     0.8147    0.6822     2.208
## pth14        0.9992     1.0008    0.9976     1.001
## ca14         1.1882     0.8416    0.7996     1.766
## phos14       0.9648     1.0365    0.7804     1.193
## alb14        0.7243     1.3806    0.3129     1.676
## catheter0    0.6858     1.4581    0.3599     1.307
## Ivvitd0      0.7125     1.4036    0.3576     1.420
## 
## Concordance= 0.677  (se = 0.041 )
## Rsquare= 0.04   (max possible= 0.752 )
## Likelihood ratio test= 17.51  on 10 df,   p=0.06379
## Wald test            = 16.47  on 10 df,   p=0.08703
## Score (logrank) test = 16.62  on 10 df,   p=0.08327

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  
## -0.9926  -0.5442  -0.4333  -0.3152   2.4809  
## 
## Coefficients:
##               Estimate Std. Error z value Pr(>|z|)   
## (Intercept) -5.0097336  2.3371762  -2.143  0.03207 * 
## group0      -0.2304286  0.3524819  -0.654  0.51328   
## Age          0.0450038  0.0148201   3.037  0.00239 **
## Race2NW      0.4303361  0.3901387   1.103  0.27001   
## diabetes0    0.2145800  0.3226116   0.665  0.50596   
## pth14       -0.0008790  0.0008885  -0.989  0.32252   
## ca14         0.1955977  0.2171938   0.901  0.36782   
## phos14      -0.0394911  0.1157190  -0.341  0.73290   
## alb14       -0.3724413  0.4692916  -0.794  0.42741   
## catheter0   -0.4056734  0.3527161  -1.150  0.25009   
## Ivvitd0     -0.3770357  0.3810761  -0.989  0.32247   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 309.37  on 430  degrees of freedom
## Residual deviance: 291.41  on 420  degrees of freedom
##   (129 observations deleted due to missingness)
## AIC: 313.41
## 
## Number of Fisher Scoring iterations: 5