Discrete-Time Survival Analysis for Heart Failure Mortality Prediction

Accurate heart-failure prognosis relies on tracking clinical risk over time, yet many machine-learning applications mishandle right-censored survival data by either discarding a patient's observation time or using it as a predictor. Discarding time ignores survival context, while using follow-up time as an input feature introduces severe target leakage that inflates apparent accuracy. We address this by proposing a discrete-time person-period framework for heart-failure mortality classification. Using the UCI Heart Failure Clinical Records cohort ($n=299$, 96 deaths), we transform the data into interval-level binary outcomes and benchmark a Cox proportional hazards baseline against person-period complementary log-log GLM and GAM models, alongside person-period random forest, XGBoost, random survival forest, and DeepSurv classifiers. The person-period GLM reproduces the Cox hazard ratios and concordance, validating the transformation, while the GAM captures significant nonlinear predictor effects and provides the best balance of discrimination and generalization; the flexible classifiers achieve strong raw performance but overfit. Finally, we quantify the leakage effect directly, including observed follow-up duration raises classification AUC from roughly 0.73 to nearly 1.00, confirming that follow-up duration must not be used as a baseline predictor. Overall, these results establish a survival-aware framework that combines flexible classification with valid time-to-event structure.