Factors influencing the prognosis of patients with heart failure with preserved ejection fraction (HFpEF) have been extensively studied. Previous studies have found that elevated serum total bilirubin levels are associated with cardiac death, heart failure readmission, and all-cause mortality in patients with chronic heart failure. However, the relationship between direct bilirubin and prognosis in patients with HFpEF is unclear.

Patients with heart failure with preserved ejection fraction account for approximately 50% of all heart failure patients, have approximately 1.4 hospitalisations per year and an annual mortality rate of approximately 15%. Till now, there have no definitively proven therapies that can reduce their morbidity and mortality, HFpEF Patients have a poor prognosis. The current study found that the prognosis of patients with HFpEF may be related to the heterogeneity of the disease, its various phenotypes and multifactorial pathophysiology, which has not been fully elucidated. The current study found that bilirubin is a risk factor for adverse outcomes of various HFpEF-related complications, but the relationship between direct bilirubin and prognosis of HFpEF has not been reported. Therefore the investigators speculate that direct bilirubin is a predictor of prognosis of HFpEF patients.

Inclusion Criteria:

• Adult aged ≥18 years old；
• Diagnosed with HFpEF.

Diagnostic criteria including:

1. left ventricular ejection fraction ≥ 50%;
2. with the symptoms and/or signs of heart failure;
3. Patients in sinus rhythm：BNP≥35pg/ml and/or NT-proBNP≥125pg/ml；Patients with atrial fibrillation：BNP≥105pg/ml and/or NT-proBNP≥365pg/ml.

Exclusion Criteria:

• LVEF less than 49% at any time

heart failure with preserved ejection fraction (HFpEF)