A retrospective analysis of outcomes among patients hospitalized with heart failure with different serum potassium levels

Abstract

Objective To compare the characteristics and outcomes among patients hospitalized with heart failure (HF) with different serum potassium levels. Methods Patients hospitalized between April 2011 and July 2015 in Nanfang Hospital of Southern Medical University were enrolled and serum levels of potassium were tested on admission. After discharge from the hospital, patients were followed-up in April and May 2016 by telephone or access to the hospital case system. The endpoint event was defined as all-cause death. Cox proportional risk regression model was used to evaluate the relationship between potassium level on admission and all-cause death after discharge. Results A total of 941 patients hospitalized with HF was enrolled, of these patients, 11.5% (108/941) had serum potassium level 5.5 mmol/L. Patients with higher baseline serum potassium levels were more likely to be older, to havea lower blood pressure, higher N-terminal pro-B type natriuretic peptide (NT-proBNP) level, to havea higher proportion of renal dysfunction and New York Heart Association (NYHA) functional class IV, and were less likely to use angiotensin converting enzyme inhibitors (ACEI)/angiotensin receptor blockers (ARB) and aldosterone antagonists at discharge (all P 5.0 mmol/L had a significantlyincreased risk of all-cause death [hazard ratio (HR) 1.05, 95% confidence interval (CI) 1.16-2.38, P=0.030], while there was no significant increase in all-cause death for patients with serum potassium level<4.0 mmol/L (HR 0.90, 95%CI 0.63-1.29, P=0.557). Conclusions Potassium disorder is common in patients hospitalized with HF. Patients with HF and higher potassium levels on admissi on are associated with increased all-cause death after discharge. Key words: Heart failure; Serum potassium; Prognosis