# Binomial Regression for Survival and Competing Risks Data

#### Klaus Holst & Thomas Scheike

#### 2026-05-24

# Binomial Regression for censored data

The `binreg` function fits a logistic link model with IPCW adjustment for a specific time-point, and can thus be used for both survival and competing risks data. Computation is linear in data size, and influence functions are computed and available for downstream calculations.

Key features:

- the censoring weights can be stratum-dependent
- predictions can be computed with standard errors
- computation time is linear in data size, including standard errors
- cluster-corrected standard errors are available via the `clusters` argument

# Details

The binreg function does direct binomial regression for one time-point, \(t\), fitting the model \[\begin{align*} P(T \leq t, \epsilon=1 | X ) & = \mbox{expit}( X^T \beta) = F_1(t,X,\beta) \end{align*}\] based on an IPCW adjusted estimating equation (EE) with response \(Y(t)=I(T \leq t, \epsilon=1 )\) \[\begin{align*} U(\beta,\hat G_c) = & X ( Y(t) \frac{ \Delta(t) }{\hat G_c(T_i \wedge t)} - \mbox{expit}( X^T \beta)) = 0, \end{align*}\] with \(G_c(t)=P(C>t)\), the censoring survival distribution, and with \(\Delta(t) = I( C_i > T_i \wedge t)\) the indicator of being uncensored at time \(t\) (type=“I”).

The default type=“II” is to augment with a censoring term, that is solve \[\begin{align*} & U(\beta,\hat G_c) + \int_0^t X \frac{\hat E(Y(t)| T>u)}{\hat G_c(u)} d\hat M_c(u) =0 \end{align*}\] where \(M_c(u)\) is the censoring martingale, this typically improves the performance. This is equivalent to the pseudo-value approach (see Overgaard (2025)).

The influence function for the type=“II” estimator is \[\begin{align*} U(\beta,G_c) + \int_0^t X \frac{E(Y| T>u)}{G_c(u)} d M_c(u) - \int_0^t \frac{E(X| T>u) E(Y| T>u)}{G_c(u)} d M_c(u) - \int_0^t \frac{E( X Y| T>u)}{G_c(u)} d M_c(u) \end{align*}\] and for type=“I” \[\begin{align*} & U(\beta) + \int_0^t \frac{E( X Y| T>u)}{G_c(u)} d M_c(u). \end{align*}\] The means \(E(X Y(t) | T>u)\) and \(E(Y(t)| T>u)\) are estimated by IPCW estimators among survivors to get estimates of the influence functions.

The function logitIPCW instead considers \[\begin{align*} U^{glm}(\beta,\hat G_c) = & \frac{ \Delta(t) }{\hat G_c(T_i \wedge t)} X ( Y(t) - \mbox{expit}( X^T \beta)) = 0. \end{align*}\] This score equation is quite similar to those of the binreg, and exactly the same when the censoring model is fully-nonparametric.

The logitIPCW has influence function \[\begin{align*} & U^{glm}(\beta,G_c) + \int_0^t \frac{E( X ( Y - F_1(t,\beta)) | T>u)}{G_c(u)} d M_c(u) \end{align*}\]

Which estimator performs the best depends on the censoring distribution and it seems that the binreg with type=“II” performs overall quite nicely (see Blanche et al (2023) and Overgaard (2025)). For the full estimated censoring model all estimators have the same influence function (see Blanche et al (2023)).

Additional functions logitATE, and binregATE computes the average treatment effect based on propensity and outcome modelling. We demonstrate this in another vignette.

The functions logitATE/binregATE can be used when there is no censoring and we thus have simple binary outcome.

The variance is based on a sandwich formula with IPCW adjustment (using the influence functions), and `naive.var` is the variance under a known censoring model. The influence functions are stored in the output. Clusters can be specified to obtain cluster-corrected standard errors.

# Examples

     library(mets)
     options(warn=-1)
     set.seed(1000) # to control output in random noise just below.
     data(bmt)
     bmt$time <- bmt$time+runif(nrow(bmt))*0.01
     bmt$id <- 1:408

     # logistic regression with IPCW binomial regression
     out <- binreg(Event(time,cause)~tcell+platelet,bmt,time=50)
     summary(out)
    #>    n events
    #>  408    160
    #>
    #>  408 clusters
    #> coeffients:
    #>              Estimate   Std.Err      2.5%     97.5% P-value
    #> (Intercept) -0.180338  0.126748 -0.428760  0.068084  0.1548
    #> tcell       -0.418545  0.345480 -1.095675  0.258584  0.2257
    #> platelet    -0.437644  0.240978 -0.909952  0.034665  0.0694
    #>
    #> exp(coeffients):
    #>             Estimate    2.5%  97.5%
    #> (Intercept)  0.83499 0.65132 1.0705
    #> tcell        0.65800 0.33431 1.2951
    #> platelet     0.64556 0.40254 1.0353

We can also compute predictions using the estimates

     predict(out,data.frame(tcell=c(0,1),platelet=c(1,1)),se=TRUE)
    #>        pred         se     lower     upper
    #> 1 0.3502406 0.04847582 0.2552280 0.4452533
    #> 2 0.2618207 0.06969334 0.1252217 0.3984196

Further the censoring model can depend on strata

     outs <- binreg(Event(time,cause)~tcell+platelet,bmt,time=50,cens.model=~strata(tcell,platelet))
     summary(outs)
    #>    n events
    #>  408    160
    #>
    #>  408 clusters
    #> coeffients:
    #>              Estimate   Std.Err      2.5%     97.5% P-value
    #> (Intercept) -0.180697  0.127414 -0.430424  0.069030  0.1561
    #> tcell       -0.365928  0.350632 -1.053154  0.321299  0.2967
    #> platelet    -0.433494  0.240270 -0.904415  0.037428  0.0712
    #>
    #> exp(coeffients):
    #>             Estimate    2.5%  97.5%
    #> (Intercept)  0.83469 0.65023 1.0715
    #> tcell        0.69355 0.34884 1.3789
    #> platelet     0.64824 0.40478 1.0381

# Absolute risk differences and ratio

Now for illustrations we consider the absolute risk difference depending on tcell

     outs <- binreg(Event(time,cause)~tcell,bmt,time=50,cens.model=~strata(tcell))
     summary(outs)
    #>    n events
    #>  408    160
    #>
    #>  408 clusters
    #> coeffients:
    #>             Estimate  Std.Err     2.5%    97.5% P-value
    #> (Intercept) -0.30054  0.11153 -0.51914 -0.08194  0.0070
    #> tcell       -0.51741  0.33981 -1.18342  0.14860  0.1278
    #>
    #> exp(coeffients):
    #>             Estimate    2.5%  97.5%
    #> (Intercept)  0.74042 0.59503 0.9213
    #> tcell        0.59606 0.30623 1.1602

the risk difference is

    ps <-  predict(outs,data.frame(tcell=c(0,1)),se=TRUE)
    ps
    #>        pred         se     lower     upper
    #> 1 0.4254253 0.02726306 0.3719897 0.4788609
    #> 2 0.3061988 0.06819019 0.1725461 0.4398516
    sum( c(1,-1) * ps[,1])
    #> [1] 0.1192264

Getting the standard errors is straightforward since the two groups are independent. If we had additionally adjusted for other covariates, however, we would need to apply the delta theorem using the relevant covariances, along the lines of:

    dd <- data.frame(tcell=c(0,1))
    p <- predict(outs,dd)

    riskdifratio <- function(p,contrast=c(1,-1)) {
       outs$coef <- p
       p <- predict(outs,dd)[,1]
       pd <- sum(contrast*p)
       r1 <- p[1]/p[2]
       r2 <- p[2]/p[1]
       return(c(pd,r1,r2))
    }

    estimate(outs,f=riskdifratio,dd,null=c(0,1,1))
    #>    Estimate Std.Err     2.5%  97.5% P-value
    #> p1   0.1192 0.07344 -0.02471 0.2632 0.10448
    #> p2   1.3894 0.32197  0.75833 2.0204 0.22652
    #> p3   0.7197 0.16679  0.39284 1.0467 0.09291
    #> ────────────────────────────────────────────────────────────
    #> Null Hypothesis:
    #>   [p1] = 0
    #>   [p2] = 1
    #>   [p3] = 1
    #>
    #> chisq = 12.0249, df = 2, p-value = 0.002448

same as

    run <- 0
    if (run==1) {
    library(prodlim)
    pl <- prodlim(Hist(time,cause)~tcell,bmt)
    spl <- summary(pl,times=50,asMatrix=TRUE)
    spl
    }

# SessionInfo

    sessionInfo()
    #> R version 4.6.0 (2026-04-24)
    #> Platform: x86_64-pc-linux-gnu
    #> Running under: Ubuntu 24.04.4 LTS
    #>
    #> Matrix products: default
    #> BLAS:   /home/kkzh/.asdf/installs/r/4.6.0/lib/R/lib/libRblas.so
    #> LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.12.0  LAPACK version 3.12.0
    #>
    #> locale:
    #>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
    #>  [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
    #>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
    #>  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
    #>  [9] LC_ADDRESS=C               LC_TELEPHONE=C
    #> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
    #>
    #> time zone: Europe/Copenhagen
    #> tzcode source: system (glibc)
    #>
    #> attached base packages:
    #> [1] stats     graphics  grDevices utils     datasets  methods   base
    #>
    #> other attached packages:
    #> [1] timereg_2.0.7  survival_3.8-6 mets_1.3.10
    #>
    #> loaded via a namespace (and not attached):
    #>  [1] cli_3.6.6              knitr_1.51             rlang_1.2.0
    #>  [4] xfun_0.57              otel_0.2.0             future.apply_1.20.2
    #>  [7] listenv_0.10.1         lava_1.9.1             stats4_4.6.0
    #> [10] grid_4.6.0             evaluate_1.0.5         yaml_2.3.12
    #> [13] mvtnorm_1.3-7          numDeriv_2016.8-1.1    compiler_4.6.0
    #> [16] codetools_0.2-20       Rcpp_1.1.1-1.1         ucminf_1.2.3
    #> [19] future_1.70.0          lattice_0.22-9         digest_0.6.39
    #> [22] parallelly_1.47.0      parallel_4.6.0         splines_4.6.0
    #> [25] Matrix_1.7-5           tools_4.6.0            RcppArmadillo_15.2.6-1
    #> [28] globals_0.19.1