Discrimination performance in illness-death models with interval-censored disease data
Marta Spreafico, Anja J. Rueten-Budde, Hein Putter, Marta Fiocco
TL;DR
This study tackles discrimination assessment for illness-death models when disease onset is interval-censored, a common situation in clinical follow-up. It compares Cox models with time-dependent markers to three interval-censored illness-death estimators (piecewise-constant, Weibull, M-spline) using time-specific AUCs for incident/dynamic and cumulative/dynamic definitions, under simulation and real soft tissue sarcoma data. Results show that ignoring interval-censoring biases parameter estimates and misrepresents discrimination; among methods, Weibull generally performs best when appropriate, but convergence and distributional fit matter, and piecewise-constant may be less flexible; M-splines offer flexibility but can face convergence issues. The findings stress incorporating interval-censoring into both estimation and discrimination evaluation to obtain reliable prognostic assessments in interval-observed disease settings, with practical implications for dynamic prediction in oncology and similar fields.
Abstract
In clinical studies, the illness-death model is often used to describe disease progression. A subject starts disease-free, may develop the disease and then die, or die directly. In clinical practice, disease can only be diagnosed at pre-specified follow-up visits, so the exact time of disease onset is often unknown, resulting in interval-censored data. This study examines the impact of ignoring this interval-censored nature of disease data on the discrimination performance of illness-death models, focusing on the time-specific Area Under the receiver operating characteristic Curve (AUC) in both incident/dynamic and cumulative/dynamic definitions. A simulation study with data simulated from Weibull transition hazards and disease state censored at regular intervals is conducted. Estimates are derived using different methods: the Cox model with a time-dependent binary disease marker, which ignores interval-censoring, and the illness-death model for interval-censored data estimated with three implementations - the piecewise-constant model from the msm package, the Weibull and M-spline models from the SmoothHazard package. These methods are also applied to a dataset of 2232 patients with high-grade soft tissue sarcoma, where the interval-censored disease state is the post-operative development of distant metastases. The results suggest that, in the presence of interval-censored disease times, it is important to account for interval-censoring not only when estimating the parameters of the model but also when evaluating the discrimination performance of the disease.
