Effects of prognostic nutritional index and obesity on 1-year mortality in patients with acute heart failure

Abstract Background Increased body mass index (BMI) has paradoxically been linked to improved survival rates among patients with acute heart failure (AHF). However, the impact of different nutritional statuses on this obesity paradox on 1-year mortality remains unclear. The prognostic nutritional index (PNI) is a simple tool to assess nutrition status. Recently, landmark findings such as the STEP-HFpEF (Semaglutide Treatment Effect in People With Obesity and HFpEF) trial showed at 1-year, semaglutide not only reduced weight considerably, but also significantly improved health-related quality of life, functional status, and CRP levels. Also, the semaglutide effects on heart disease and stroke in patients with overweight or obesity (SELECT) trial demonstrated a 20% reduction in cardiovascular outcomes. Purpose To investigate the association between obesity and AHF on all-cause mortality according to nutritional status. Methods The cohort study comprised 7258 patients with a cardiopulmonary condition, all of whom were admitted and included on-site at the Emergency Department (ED) in a large University Hospital in Denmark, between March 2020 and March 2022. The follow-up time was at least 365 days. 408 patients with AHF were identified by chart review by trained cardiologists for analysis. PNI was calculated according to the formula: 10×serum albumin (g/ dL) + 5×total lymphocyte count×109/L. A value ≥ 38 is considered well-nourished, and a value < 38 is considered malnourished. Patients were divided into High-PNI (≥38) and Low-PNI (<38) according to cut-off value of PNI. The Kaplan-Meier (KM) curves were used to analyze cumulative survival in each subgroup, and the log-rank test was used to compare differences between groups. Cox regression models were used to analyze associa­tions between BMI, nutritional status and outcomes, expressed as hazard ratios (HR) and relative 95% confi­dence intervals (CI). Results Amongst 408 hospitalized AHF patients, 384 (mean age 75.6 ±11.7) with available PNI scores were enrolled into this study. 55.7% (n=214) were male, 56.4% (n=93) died in the Low-PNI group and 34.2% (n=75) died in the High-PNI group within 1 year. After adjusting for potential confounders in the High-PNI population, compared with the under/normal and overweight BMI group, obesity was negatively associated with 1-year mortality, with adjusted HR of 0.47, 95% CI (0.24–0.94), P = 0.033. However, this correlation disappeared in the Low-PNI group (obese BMI: HR 1.2, 95% CI 0.71–2.1, P = 0.457). In addition, those who were overweight in the Low-PNI group had an 80% increase in 1-year risk of death. Conclusion Obesity (BMI>30) was associated with reduced 1-year mortality only in AHF-patients with good nutritional status. However, this association disappeared in malnourished patients. Consequently, additional research is essential to formulate weight loss recommendations for malnourished obese patients with AHF.