Methods are developed to estimate and test for the impact of intervention use on a population's survival function (time to AIDS). Each participant's history is divided into J + 1 components: Ωo occurring before the intervention is available and Ω1 to ΩJ occurring later, as the intervention becomes successively more available. Distribution free truncated Kaplan‐Meier models based on time since exposure fit separately to the risk sets/outcomes in Ωo to ΩJ directly show the changing patterns of survival. Multivariate proportional hazards models can be used to adjust for covariates. Application of these methods indicates that availability of proven anti‐AIDS interventions may have delayed time to AIDS by 8 months in an educated HIV‐1 infected homosexual cohort with good access to medical care.
ASJC Scopus subject areas
- Statistics and Probability