The spot urinary potassium-to-creatinine (uK/uCr) ratio has been proposed as a surrogate for 24-h potassium excretion, but its clinical determinants and prognostic significance in heart failure (HF) remain unclear. We evaluated the clinical variables associated with the uK/uCr ratio and its relationship with long-term mortality in ambulatory HF patients. We ambispectively analyzed 1,145 patients from a single-center HF clinic. A multivariable linear regression model was used to identify factors independently associated with the uK/uCr ratio, and Cox models assessed its prognostic value. Mean age was 73.2 ± 11.3 years, 41.5% were women, and 52.0% had HF with preserved ejection fraction. Median NT-proBNP and uK/uCr were 1324 (447–2952) pg/mL and 48 (36–62) mmol/g creatinine, respectively. Higher uK/uCr was independently associated with estimated glomerular filtration rate (28.3% of R2), furosemide dose (20.6%), BUN (16.5%), age (13.5%), and NT-proBNP (8.2%). Each 10-unit increase in uK/uCr was associated with increased all-cause (HR 1.031; 95% CI: 1.006–1.056; p = 0.014) and cardiovascular mortality (HR 1.039; 95% CI: 1.021–1.057; p < 0.001). In conclusion, the uK/uCr ratio reflects renal function, diuretic intensity, and neurohormonal activation, and is an independent predictor of mortality, suggesting its potential role in risk stratification and therapeutic decision-making in HF.
Miñana et al. (Thu,) studied this question.