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Comparative Study
. 2002;11(2):68-74.
doi: 10.1002/mpr.124.

Graphing survival curve estimates for time-dependent covariates

Lonni R Schultz  1 , Edward L Peterson, Naomi Breslau
Affiliations
Comparative Study

Graphing survival curve estimates for time-dependent covariates

Lonni R Schultz et al. Int J Methods Psychiatr Res. 2002.

Abstract

Graphical representation of statistical results is often used to assist readers in the interpretation of the findings. This is especially true for survival analysis where there is an interest in explaining the patterns of survival over time for specific covariates. For fixed categorical covariates, such as a group membership indicator, Kaplan-Meier estimates (1958) can be used to display the curves. For time-dependent covariates this method may not be adequate. Simon and Makuch (1984) proposed a technique that evaluates the covariate status of the individuals remaining at risk at each event time. The method takes into account the change in an individual's covariate status over time. The survival computations are the same as the Kaplan-Meier method, in that the conditional survival estimates are the function of the ratio of the number of events to the number at risk at each event time. The difference between the two methods is that the individuals at risk within each level defined by the covariate is not fixed at time 0 in the Simon and Makuch method as it is with the Kaplan-Meier method. Examples of how the two methods can differ for time dependent covariates in Cox proportional hazards regression analysis are presented.

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References

    1. Anthony JC, Petronis KR. Early‐onset drug use and risk of later drug problems. Drug and Alcohol Dependence 1995; 40: 9–15. - PubMed
    1. Breslau N, Schultz L, Peterson E. Sex differences in depression: a role for pre‐existing anxiety. Psychiatry Research 1995; 58: 1–12. - PubMed
    1. Breslau N, Peterson EL, Schultz LR, Andreski P, Chilcoat H. Are smokers with alcohol disorders less likely to quit? American Journal of Public Health 1996; 86: 985–90. - PMC - PubMed
    1. Breslau N, Peterson EL, Schultz LR, Chilcoat H, Andreski P. Major depression and stages of smoking. Archives of General Psychiatry 1998; 55: 161–6. - PubMed
    1. Breslau N, Schultz LR, Stewart WF, Lipton RB, Lucia VC, Welch KMA. Headache and major depression: is the association specific to migraine? Neurology 2000; 54: 308–13. - PubMed

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