Short-Term Changes in Serum Potassium and the Risk of Subsequent Vascular Events and Mortality: Results from a Randomized Controlled Trial of ACE Inhibitors

BACKGROUND AND OBJECTIVES: Hyperkalemia after starting renin-angiotensin system inhibitors has been shown to be subsequently associated with a higher risk of cardiovascular and kidney outcomes. However, whether to continue or discontinue the drug after hyperkalemia remains unclear. 

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Data came from the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial, which included a run-in period where all participants initiated angiotensin-converting enzyme inhibitor-based therapy (a fixed combination of perindopril and indapamide). The study population was taken as patients with type 2 diabetes with normokalemia (serum potassium of 3.5 to <5.0 mEq/L) at the start of run-in. Potassium was remeasured 3 weeks later when a total of 9694 participants were classified into hyperkalemia (≥5.0 mEq/L), normokalemia, and hypokalemia (<3.5 mEq/L) groups. After run-in, patients were randomized to continuation of the angiotensin-converting enzyme inhibitor-based therapy or placebo; major macrovascular, microvascular, and mortality outcomes were analyzed using Cox regression during the following 4.4 years (median). 

RESULTS: During active run-in, 556 (6%) participants experienced hyperkalemia. During follow-up, 1505 participants experienced the primary composite outcome of major macrovascular and microvascular events. Randomized treatment of angiotensin-converting enzyme inhibitor-based therapy significantly decreased the risk of the primary outcome (38.1 versus 42.0 per 1000 person-years; hazard ratio, 0.91; 95% confidence interval, 0.83 to 1.00; P=0.04) compared with placebo. The magnitude of effects did not differ across subgroups defined by short-term changes in serum potassium during run-in (P for heterogeneity =0.66). Similar consistent treatment effects were also observed for all-cause death, cardiovascular death, major coronary events, major cerebrovascular events, and new or worsening nephropathy (P for heterogeneity ≥0.27). 

CONCLUSIONS: Continuation of angiotensin-converting enzyme inhibitor-based therapy consistently decreased the subsequent risk of clinical outcomes, including cardiovascular and kidney outcomes and death, regardless of short-term changes in serum potassium. 

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE), NCT00145925.