AimsHeart failure with preserved ejection fraction (HFpEF) has several pathophysiological aspects, including stiffness and/or congestion of multiple organs. Poor prognosis is expected in heart failure patients with liver stiffness, which has recently been assessed by non‐alcoholic fatty liver disease fibrosis score (NFS; based on aspartate aminotransferase to alanine aminotransferase ratio, platelet counts, and albumin). We aimed to investigate the impact of NFS on prognosis of HFpEF patients, with consideration for the peripheral collagen markers such as procollagen type III peptide (PIIIP), type IV collagen 7S, and hyaluronic acid.Methods and resultsWe performed a prospective observational study. Consecutive 492 hospitalized HFpEF patients were divided into four groups based on their NFS: first–fourth quartiles (n = 123). The fourth quartile group had the highest levels of PIIIP, type IV collagen 7S, hyaluronic acid, and B‐type natriuretic peptide (P<0.001 each). In addition, there were significant positive correlations between PIIIP, type IV collagen 7S, hyaluronic acid, B‐type natriuretic peptide, and NFS (P < 0.001 each). In the follow‐up period (mean 1107 days), 93 deaths occurred. All‐cause mortality increased in all four quartiles (8.1%, 12.2%, 23.6%, and 31.7%, P < 0.001). In the multivariable Cox proportional hazard analysis, NFS was an independent predictor of all‐cause mortality in the HFpEF patients.ConclusionsNFS, a novel indicator of liver fibrosis, correlates with circulating systemic markers of fibrosis and congestion and is associated with higher all‐cause mortality in HFpEF patients. NFS can be calculated simply and may be a useful tool to assess liver stiffness and prognosis in HFpEF patients.