Association between the alkaline phosphatase-to-albumin ratio and recorded early all-cause mortality within 90 days of admission in patients with heart failure: a retrospective cohort study in a Chinese population.

Background: APAR combines alkaline phosphatase and albumin, two routine laboratory measurements. We examined its association with recorded early all-cause mortality within 90 days of admission in hospitalized patients with heart failure (HF), prioritizing continuous APAR over a mortality-derived cutoff. Methods: We analyzed version 1.3 of the Zigong Heart Failure Database. Among 2,008 patients, 1,906 had calculable APAR and a recorded vital-status outcome within 90 days; 37 deaths were recorded. Exact event times were available for 1,905 patients (36 deaths). The primary model assessed standardized ln(APAR), adjusting for the eight released age categories as a 1-8 ordinal score, sex, log(BNP), eGFR, sodium, and CCI, with NYHA class stratification. Mortality timing, post-discharge survival, hemoglobin adjustment, and E-values were examined in sensitivity analyses. Results: Recorded all-cause mortality within 90 days of admission was 1.94%. In the complete-case model ( Conclusion: Higher admission ln(APAR) was associated with recorded early all-cause mortality within 90 days of admission, but the association was modest, nonlinear, scale-dependent, and based on few events. Post-discharge estimates were directionally consistent but imprecise. External validation is required before APAR or any cutoff is used for clinical risk stratification.