173 lines
6.6 KiB
R
173 lines
6.6 KiB
R
library(survival)
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aeq <- function(x, y, ...) all.equal(as.vector(x), as.vector(y), ...)
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# Check that estimates from a multi-state model agree with single state models
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# Use a simplified version of the myeloid data set
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tdata <- tmerge(myeloid[,1:3], myeloid, id=id, death=event(futime,death),
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priortx = tdc(txtime), sct= event(txtime))
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tdata$event <- factor(with(tdata, sct + 2*death), 0:2,
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c("censor", "sct", "death"))
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fit <- coxph(Surv(tstart, tstop, event) ~ trt + sex, tdata, id=id,
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iter=4, x=TRUE, robust=FALSE)
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fit12 <- coxph(Surv(tstart, tstop, event=='sct') ~ trt + sex, tdata,
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subset=(priortx==0), iter=4, x=TRUE)
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fit13 <- coxph(Surv(tstart, tstop, event=='death') ~ trt + sex, tdata,
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subset=(priortx==0), iter=4, x=TRUE)
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fit23 <- coxph(Surv(tstart, tstop, event=='death') ~ trt + sex, tdata,
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subset=(priortx==1), iter=4, x=TRUE)
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aeq(coef(fit), c(coef(fit12), coef(fit13), coef(fit23)))
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aeq(fit$loglik, fit12$loglik + fit13$loglik + fit23$loglik)
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temp <- matrix(0, 6,6)
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temp[1:2, 1:2] <- fit12$var
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temp[3:4, 3:4] <- fit13$var
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temp[5:6, 5:6] <- fit23$var
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aeq(fit$var, temp)
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# check out model.frame
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fita <- coxph(Surv(tstart, tstop, event) ~ trt, tdata, id=id)
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fitb <- coxph(Surv(tstart, tstop, event) ~ trt, tdata, id=id, model=TRUE)
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all.equal(model.frame(fita), fitb$model)
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# model.frame fails due to an interal rule in R, factors vs characters
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# result when the xlev arg is in the call. So model.frame(fita) has trt
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# as a factor, not character.
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#check residuals
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indx1 <- which(fit$rmap[,2] ==1)
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indx2 <- which(fit$rmap[,2] ==2)
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indx3 <- which(fit$rmap[,2] ==3)
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aeq(residuals(fit), c(residuals(fit12), residuals(fit13), residuals(fit23)))
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aeq(residuals(fit)[indx1], residuals(fit12))
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aeq(residuals(fit)[indx2], residuals(fit13))
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aeq(residuals(fit)[indx3], residuals(fit23))
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# score residuals
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temp <- residuals(fit, type='score')
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aeq(temp[indx1, 1:2], residuals(fit12, type='score'))
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aeq(temp[indx2, 3:4], residuals(fit13, type='score'))
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aeq(temp[indx3, 5:6], residuals(fit23, type='score'))
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all(temp[indx1, 3:6] ==0)
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all(temp[indx2, c(1,2,5,6)] ==0)
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all(temp[indx3, 1:4]==0)
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temp <- residuals(fit, type="dfbeta")
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all(temp[indx1, 3:6] ==0)
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all(temp[indx2, c(1,2,5,6)] ==0)
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all(temp[indx3, 1:4]==0)
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aeq(temp[indx1, 1:2], residuals(fit12, type='dfbeta'))
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aeq(temp[indx2, 3:4], residuals(fit13, type='dfbeta'))
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aeq(temp[indx3, 5:6], residuals(fit23, type='dfbeta'))
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temp <- residuals(fit, type="dfbetas")
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all(temp[indx1, 3:6] ==0)
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all(temp[indx2, c(1,2,5,6)] ==0)
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all(temp[indx3, 1:4]==0)
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aeq(temp[indx1, 1:2], residuals(fit12, type='dfbetas'))
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aeq(temp[indx2, 3:4], residuals(fit13, type='dfbetas'))
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aeq(temp[indx3, 5:6], residuals(fit23, type='dfbetas'))
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# Schoenfeld and scaled shoenfeld have one row per event
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sr1 <- residuals(fit12, type="schoenfeld")
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sr2 <- residuals(fit13, type="schoenfeld")
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sr3 <- residuals(fit23, type="schoenfeld")
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end <- rep(1:3, c(nrow(sr1), nrow(sr2), nrow(sr3)))
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temp <- residuals(fit, type="schoenfeld")
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aeq(temp[end==1, 1:2], sr1)
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aeq(temp[end==2, 3:4], sr2)
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aeq(temp[end==3, 5:6], sr3)
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all(temp[end==1, 3:6] ==0)
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all(temp[end==2, c(1,2,5,6)] ==0)
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all(temp[end==3, 1:4] ==0)
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#The scaled Schoenfeld don't agree, due to the use of a robust
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# variance in fit, regular variance in fit12, fit13 and fit23
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#Along with being scaled by different event counts
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xfit <- fit
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xfit$var <- xfit$naive.var
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if (FALSE) {
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xfit <- fit
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xfit$var <- xfit$naive.var # fixes the first issue
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temp <- residuals(xfit, type="scaledsch")
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aeq(d1* temp[sindx1, 1:2], residuals(fit12, type='scaledsch'))
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aeq(temp[sindx2, 3:4], residuals(fit13, type='scaledsch'))
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aeq(temp[sindx3, 5:6], residuals(fit23, type='scaledsch'))
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}
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if (FALSE) { # the predicted values are a work in progress
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# predicted values differ because of different centering
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c0 <- sum(fit$mean * coef(fit))
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c12 <- sum(fit12$mean * coef(fit12))
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c13 <- sum(fit13$mean* coef(fit13))
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c23 <- sum(fit23$mean * coef(fit23))
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aeq(predict(fit)+c0, c(predict(fit12)+c12, predict(fit13)+c13,
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predict(fit23)+c23))
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aeq(exp(predict(fit)), predict(fit, type='risk'))
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# expected survival is independent of centering
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aeq(predict(fit, type="expected"), c(predict(fit12, type="expected"),
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predict(fit13, type="expected"),
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predict(fit23, type="expected")))
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}
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# predict(type='terms') is a matrix, centering changes as well
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if (FALSE) {
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temp <- predict(fit, type='terms')
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all(temp[indx1, 3:6] ==0)
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all(temp[indx2, c(1,2,5,6)] ==0)
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all(temp[indx3, 1:4]==0)
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aeq(temp[indx1, 1:2], predict(fit12, type='terms'))
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aeq(temp[indx2, 3:4], predict(fit13, type='terms'))
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aeq(temp[indx3, 5:6], predict(fit23, type='terms'))
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} # end of prediction section
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# The global and per strata zph tests will differ for the KM or rank
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# transform, because the overall and subset will have a different list
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# of event times, which changes the transformed value for all of them.
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# But identity and log are testable.
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test_a <- cox.zph(fit, transform="log",global=FALSE)
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test_a12 <- cox.zph(fit12, transform="log",global=FALSE)
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test_a13 <- cox.zph(fit13, transform="log", global=FALSE)
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test_a23 <- cox.zph(fit23, transform="log", global=FALSE)
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aeq(test_a$y[test_a$strata==1, 1:2], test_a12$y)
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aeq(test_a$table[1:2,], test_a12$table)
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aeq(test_a$table[3:4,], test_a13$table)
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aeq(test_a$table[5:6,], test_a23$table)
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# check cox.zph fit - transform = 'identity'
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test_b <- cox.zph(fit, transform="identity",global=FALSE)
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test_b12 <- cox.zph(fit12, transform="identity",global=FALSE)
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test_b13 <- cox.zph(fit13, transform="identity", global=FALSE)
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test_b23 <- cox.zph(fit23, transform="identity", global=FALSE)
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aeq(test_b$table[1:2,], test_b12$table)
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aeq(test_b$table[3:4,], test_b13$table)
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aeq(test_b$table[5:6,], test_b23$table)
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# check out subscripting of a multi-state zph
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cname <- c("table", "x", "time", "y", "var")
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sapply(cname, function(x) aeq(test_b[1:2]$x, test_b12$x))
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sapply(cname, function(x) aeq(test_b[3:4]$x, test_b13$x))
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sapply(cname, function(x) aeq(test_b[5:6]$x, test_b23$x))
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# check model.matrix
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mat1 <- model.matrix(fit)
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all.equal(mat1, fit$x)
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# Check that the internal matix agrees (uses stacker, which is not exported)
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mat2 <- model.matrix(fit12)
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mat3 <- model.matrix(fit13)
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mat4 <- model.matrix(fit23)
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# first reconstruct istate
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tcheck <- survcheck(Surv(tstart, tstop, event) ~ 1, tdata, id=id)
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temp <- survival:::stacker(fit$cmap, fit$smap, as.numeric(tcheck$istate), fit$x,
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fit$y, NULL, fit$states)
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aeq(temp$X[temp$transition==1, 1:2], mat2)
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aeq(temp$X[temp$transition==2, 3:4], mat3)
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aeq(temp$X[temp$transition==3, 5:6], mat4)
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