ah: Fit Additive Hazards Regression Models

In katehu/addhazard: Fit Additive Hazards Models for Survival Analysis

Description

Fit a semiparametric additive hazard model '

λ(t|Z=z) = λ_0(t) + β'z.

The estimating procedures follow Lin & Ying (1994).

Usage

ah(formula, data, robust, weights, ties, seed = 20, ...)

Arguments

formula	a formula object for the regression model of the form response ~ predictors. The outcome is a survival object created by Surv.
data	a data frame. Input dataset.
robust	a logical variable. Robust standard errors are provided if robust == TRUE.
weights	a numeric vector. The weight of each observation.
ties	a string. If there are ties in the survival time, when ties = 'break' a small random number is added to the survival time to break the ties.
seed	an integer. Seed number used to generate random increment when breaking ties. The default number is 20.
...	additional arguments to be passed to the low level regression fitting functions.

Value

An object of class 'ah' representing the fit.

Note

The response variable is a survival object. The regression model can be univariate or multivariate. This function is built upon the function ahaz by Anders Gorst-Rasmussen.

References

Lin, D.Y. & Ying, Z. (1994). Semiparametric analysis of the additive risk model. Biometrika; 81:61-71.

See Also

predict.ah for prediction based on fitted ah model, nwtsco for the description of nwtsco dataset

Examples

library(survival)
### using the first 100 rows in nwtsco to build an additive hazards model
nwts<- nwtsco[1:100,]

### fit the additive hazards model to the data
### the model-based standard errors are reported when setting robust = FALSE
fit1 <- ah(Surv(trel,relaps) ~ age + instit, data = nwts, robust = FALSE)
summary(fit1)

### fit the additive hazards model to the data with robust standard errors
fit2 <- ah(Surv(trel,relaps) ~ age + instit, data = nwts, robust = TRUE)
summary(fit2)

### when there are ties, break the ties by setting ties = 'break'
nwts_all <- nwtsco
fit3 <- ah(Surv(trel,relaps) ~ age + instit, ties = 'break', data = nwts_all, robust = TRUE)
summary(fit3)
### users could break the ties on their own by
nwts_all$trel <- nwtsco$trel + runif(dim(nwts_all)[1],0,1)*1e-10
fit3 <- ah(Surv(trel,relaps) ~ age + instit, data = nwts_all, robust = TRUE)
summary(fit3)

katehu/addhazard documentation built on July 20, 2020, 5:06 a.m.