BACKGROUND: The circadian system influences the pathophysiology of many cardiovascular diseases
however, circadian variations in patients with heart failure with preserved ejection fraction (HFpEF) are unknown. Thus, this study aimed to compare the clinical characteristics and risk factors for in-hospital mortality between patients with daytime- versus nighttime-onset HFpEF. METHODS: This multicenter retrospective study included 3875 consecutive patients with acute HFpEF. Daytime and nighttime periods were defined as 6:00-17:59 and 18:00-5:59, respectively. Potential prognostic factors for in-hospital mortality were selected using univariable analyses. Those with P values of <
0.10 were used in multivariable logistic regression analyses with forward selection (likelihood ratios) to identify significant prognostic factors. RESULTS: The incidence of daytime-onset HFpEF was significantly lower but the in-hospital mortality was significantly higher than that of nighttime-onset HFpEF. Independent prognostic factors for in-hospital mortality in patients with daytime-onset HFpEF were age (odds ratio [OR], 1.057) and systolic blood pressure (OR: 0.979). In contrast, age (OR: 1.067), coexisting atrial fibrillation/flutter (OR: 2.023), systolic blood pressure (OR: 0.989), estimated glomerular filtration rate (OR: 0.971), treatment with diuretics (OR: 0.282), and treatment with beta-blockers (OR: 0.514) were independent prognostic factors in patients with nighttime-onset HFpEF. CONCLUSIONS: The incidence of acute HFpEF exhibits circadian variations, and onset-related differences in clinical characteristics and prognostic factors for in-hospital mortality were identified. These findings may provide new insights for future research and guide individualized patient management strategies.