Prospective validation of a japanese diet–specific salt checklist in ambulatory patients with prior heart failure hospitalization

Background Dietary sodium restriction is widely recommended in heart failure (HF) management (1); however, practical tools to quantify habitual salt intake in routine clinical practice remain limited, particularly within Japanese dietary patterns. Conventional assessment methods may not adequately capture sodium sources characteristic of Japanese cuisine, including soy sauce–based seasonings and miso soup. Purpose To prospectively evaluate the construct validity of a Japanese diet–specific salt checklist (2) against urine-estimated salt intake and to examine whether associations differ according to ejection fraction (EF) phenotype and loop diuretic use. Methods We conducted a prospective cohort study of ambulatory HF patients with prior hospitalization. At baseline, salt checklist scores and urine-estimated salt intake from spot urine were obtained. Construct validity was assessed using Spearman correlation and regression analyses per 1-SD increase in score. Patients were stratified by EF (<50% vs ≥50%) and loop diuretic use. Interaction models evaluated effect modification. Results Among 174 patients, the salt checklist score showed a modest but significant correlation with urine-estimated salt intake (ρ=0.214, p=0.005). Median estimated salt intake increased stepwise across score tertiles (Low 7.9 g, Mid 8.3 g, High 9.1 g; Kruskal–Wallis p=0.011), supporting discriminative capacity. In EF-stratified analyses, HFpEF (EF ≥50%; n=128) demonstrated a significant correlation (ρ=0.332, p<0.001), whereas HFrEF (EF <50%) showed no significant association (ρ=−0.125, p=0.41). The interaction between score and EF category was significant (p=0.013). In HFpEF, each 1-SD increase in score was associated with a 0.89 g/day higher urine-estimated salt intake (95% CI 0.37–1.40, p=0.001). Loop diuretic use attenuated overall correlations (Loop+: ρ=0.14, p=0.16; Loop−: ρ=0.35, p=0.003), consistent with pharmacologic modulation of sodium handling. Conclusions In this prospective cohort of ambulatory HF patients with prior hospitalization, a Japanese diet–specific salt checklist demonstrated significant construct validity against urine-estimated salt intake, with stronger associations observed in HFpEF. These findings suggest EF-dependent differences in dietary sodium assessment and support the potential utility of this culturally tailored checklist for outpatient dietary management in HFpEF.