Evaluation of sodium intake for the prediction of cardiovascular events in Japanese high-risk patients: the ESPRIT Study

The optimal level of sodium intake remains controversial, and the effects on a broad range of cardiovascular (CV) conditions remain unknown. The Evaluation of sodium intake for the prediction of cardiovascular events in Japanese high-risk patients (ESPRIT) is a prospective observational study designed to investigate whether sodium intake assessed by spot urine testing is associated with adverse CV events. A total of 520 patients who visited our cardiology clinic with various cardiovascular risk profiles were included. Sodium intake was estimated by spot urine testing at the time of entry, and the measurement was repeated at least every 6 months during follow-up. The primary endpoint was composed of (1) hospitalization due to heart failure, (2) acute coronary syndrome, (3) cerebrovascular events, and (4) documented CV deaths. The secondary endpoint was all-cause mortality. During the median follow-up period of 5.2 years, there were 105 composite CV events (3.9%/year), including 60 hospitalizations due to heart failure, 9 acute coronary syndromes, 21 cerebrovascular events, 15 CV deaths, and 26 cases of all-cause mortality. The average sodium excretion (from a median of 14 measurements) during the follow-up period was 3.52 ± 0.67 g/day. After adjustment for age, sex, and body weight, higher sodium excretion (≥ 4.0 g/day) was associated with composite CV events (hazard ratio 1.79, confidence interval 1.01–3.15 compared with the reference value of 3.0–3.49 g/day) but not all-cause mortality. The ESPRIT study showed that high sodium excretion (≥ 4.0 g/day) was associated with the predefined composite CV events (UMIN ID: UMIN000005419).