Relationship between serum potassium concentration, NT-pro-BNP, and risk of MACE in elderly patients with chronic heart failure

Background: This study aimed to investigate the association between serum potassium concentration, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) levels, and short-term major adverse cardiovascular events (MACE) in elderly patients with chronic heart failure (CHF) after percutaneous coronary intervention (PCI), and to evaluate their predictive value. Methods: General clinical characteristics, echocardiographic parameters, and laboratory indices were collected from 124 enrolled patients. All patients were followed for 3 months beginning immediately after PCI, encompassing both the in-hospital and post-discharge periods. According to the occurrence of MACE (defined as cardiovascular death, non-fatal myocardial infarction, stroke, or rehospitalization due to worsening heart failure) during follow-up, patients were categorized into a MACE group (n=44) and a non-MACE group (n=80). Multivariate logistic regression analysis was performed to identify independent factors associated with MACE. Restricted cubic spline (RCS) analysis was used to evaluate the dose-response relationships between serum potassium concentration, NT-pro-BNP levels, and MACE risk. Receiver operating characteristic (ROC) curve analysis was conducted to assess the predictive performance of each indicator individually and in combination. Results: Multivariate logistic regression analysis demonstrated that each natural log-unit increase in NT-pro-BNP (corresponding to an approximately 2.72-fold increase in NT-pro-BNP concentration) was an independent risk factor for MACE (odds ratio [OR] =1.27), whereas each 0.1 mmol/L increase in serum potassium concentration was independently associated with a lower risk of MACE (OR =0.82). RCS analysis revealed a non-linear inverse association between serum potassium concentration and MACE risk, whereas NT-pro-BNP levels showed a significant positive association with MACE risk. The area under the ROC curve for the combined assessment of serum potassium and NT-pro-BNP was 0.73, which was significantly greater than that of either biomarker alone. Conclusion: Hypokalemia and elevated NT-pro-BNP levels are closely associated with an increased short-term risk of MACE in elderly patients with CHF. The combined assessment of these two indicators may provide clinical value for the early identification of high-risk patients.