Linkage among NT-proBNP, NYHA class and mortality in chronic heart failure: a retrospective study

Background. Heart failure (HF) is a significant worldwide concern due to its substantial impact on mortality rates and recurrent hospitalisations, especially in elderly patients. Aim. The aim of this study was to evaluate the distribution of patients according to the New York Heart Association (NYHA) classes, differences between classes in terms of age, gender, heart failure etiology, NTproBNP levels, left ventricular ejection fraction (LVEF), and outcomes. Methods. The data of 1203 heart failure patients hospitalised in the Department of Cardiology, Kaunas Hospital of Lithuanian University of Health Sciences in the period of 2022–2023 were involved into this retrospective study. Study data was collected from medical records (sociodemographic characteristics, clinical presentation of HF, biochemical and echocardiographic findings). Statistical data analysis was performed using the IBM SPSS Statistics 29.0 software. The normality of data was assessed with Kolmogorov–Smirnov test. Kruskal–Wallis and Chi-square tests were used. Data differences were considered statistically significant at p < 0.05. Results. The study included 518 (43.1%) men and 685 (56.9%) women. One (0.1%) of HF patients were classified as NYHA class I, 29 (2.4%) — as NYHA class II, 1033 (85.9%) — as NYHA class III, and 93 (7.7%) — as NYHA class IV. No statistically significant association was found between NYHA classes and gender, age, or HF etiology respectively, p = 0.497, p = 0.725, p = 0.122. Significant differences in NT-proBNP levels were observed between NYHA classes: a statistically significant difference in NT-proBNP levels was found between NYHA class I and class IV (p < 0.001), II–IV (p < 0.001), III–IV (p = 0.017). NT-proBNP levels increased with higher NYHA class: 1.007 ng/l (362 – 3.468) in NYHA class II, 4.188 ng/l (1.567 – 8.990) in NYHA class III, and 7.436 ng/L (2.652 – 20.595) in NYHA class IV (p < 0.05). LVEF was significantly more reduced in higher NYHA class: 46% and 34% in NYHA class II and class IV (p 0.001), 39% and 34% in NYHA class III–IV (p 0.001), 50% and 39% in NYHA class I–III (p = 0.001). Mortality was significantly higher in patients with a higher NYHA class (p 0.001), accordingly, 0%, 3.4%, 4.9%, and 18.3%. A statistically significant association was found between NT-proBNP and mortality (p < 0.001). Conclusion. Patients with higher NYHA class had a statistically significant increase in blood of NT-proBNP levels and significant reductions in LVEF. Higher NYHA classes were also associated with worse outcomes.