Onset of Heart Failure Identification Protocol

The primary endpoint was the onset of HF identified as the first between the following events: diagnosis of HF during hospitalization (ICD-9 codes: 39891, 40201, 40211, 40291, 40401, 40403, 40411, 40413, 40491, 40493, 4280–4284, 4289) and diagnosis of HF based at out-of-hospital clinical examination. Diagnosis of HF was performed according to ESC criteria: typical symptoms (breathlessness, ankle swelling and fatigue) and/or signs (elevated jugular venous pressure, pulmonary crackles and peripheral oedema) in presence of a structural and/or functional cardiac abnormality. Follow-up period for HF onset started at the index visit and ended on the administrative censoring date December 31, 2019. Death as a competing risk was not taken into account after an analysis of the Kaplan-Meier curve that showed a negligible bias within the first 60 months (S1 Fig). Baseline characteristics were compared between HF and HF-free individuals using chi-square test for categorical variables and t-test for continuous variables (or Mann-Whitney test, when appropriate).