Incidence and Predictors of Hyperkalemia in Patients With Heart Failure: An Analysis of the CHARM Program Akshay S. Desai, Karl Swedberg, John J. V. McMurray, Christopher B. Granger, Salim Yusuf, James B. Young, Mark E. Dunlap, Scott D. Solomon, James W. Hainer, Bertil Olofsson, Eric L. Michelson, Marc A. Pfeffer We examined the incidence and predictors of hyperkalemia in a broad population of patients with symptomatic heart failure enrolled in the CHARM (Candesartan in Heart Failure-Assessment of Reduction in Mortality and Morbidity) Program. Independent of assignment to candesartan or placebo, the risk of hyperkalemia increased with advanced age, male gender, baseline hyperkalemia, renal failure, diabetes, and background use of angiotensin-converting enzyme inhibitors or spironolactone. Candesartan increased the observed rate of hyperkalemia in these subgroups but was associated with a consistent reduction in the risk of cardiovascular death or heart failure hospitalization. Although renin-angiotensin-aldosterone antagonists improve clinical outcomes in heart failure patients, careful surveillance of serum potassium and creatinine is essential.