Competing Risk Prediction of COVID-19 Hospital Mortality with Model Diagnostics and Exploratory Evaluation in Mexico

Background/Objectives: We evaluated six-predictor cause-specific models for 45-day in-hospital COVID-19 mortality, including departures from proportional hazards and linearity and transport to Mexican data.

Methods

The oxygenation-expanded Barcelona cohort included 1622 adults. Recorded arterial PaO2/FiO2 (P/F) was preferred; otherwise P/F was derived from documented saturation and inspired oxygen using the Rice relationship at SpO2 ≤ 97%. Linear cause-specific Cox models for death and discharge served as a reference. Quadratic and time-varying extensions were assessed by three repetitions of five-fold cross-validation. Frozen Barcelona models were evaluated in a separate Mexican workbook using reconstructed day-45 outcomes and minimum-oxygenation proxies. Historical supplied scores for 634 patients were analysed separately.