Elevated Uric Acid Prevalence and Clinical Outcomes in Patients with Heart Failure with Preserved Ejection Fraction: Insights from RELAX

Purpose We aimed to 1) describe characteristics of patients with heart failure with preserved ejection fraction (HFpEF) enrolled in RELAX stratified by normal or elevated baseline serum uric acid (sUA) level; 2) evaluate the association between sUA level and surrogate clinical measures; and 3) assess associations between changes in sUA level over time and changes in surrogate clinical measures. Methods We analyzed 212 patients with HFpEF and normal or elevated (>6 mg/dL) baseline sUA measurements from the RELAX trial. Variables examined included clinical characteristics, cardiopulmonary exercise testing, 6-minute walk testing, quality of life, echocardiography, and serum biomarker testing. Baseline characteristics between groups were compared and scatter plots with quadratic regression lines and linear regression modeling were used to assess the relationship between baseline sUA and clinical measures. Kaplan–Meier curves were used to describe composite death or cardiovascular/renal hospitalization. Results The prevalence of elevated baseline sUA was 68.9%. Patients with elevated sUA had more baseline comorbidities and poorer functional status on cardiopulmonary exercise testing than those without. After adjustment, significant associations between baseline sUA levels and cystatin C, N-terminal pro B-type natriuretic peptide, high-sensitivity troponin I, and high-sensitivity C-reactive protein were identified. Higher baseline sUA was also associated with worsening peak VO2, 6-minute walk testing, and left ventricular mass. No significant association was found between baseline sUA levels and the composite of death or cardiovascular/renal hospitalization at 24 weeks. Conclusion sUA is an important marker of comorbidities and functional status in patients with HFpEF. Clinical trials of sUA-lowering therapies in patients with HFpEF are promising.