The association between short-term changes in serum potassium after initiating angiotensin-converting enzyme (ACE) inhibitor–based therapy and subsequent risk of major clinical outcomes. Short-term changes in serum potassium were defined on the basis of the measurement made 3 weeks after initiating ACE inhibitor–based therapy. Models were adjusted for age, sex, region of residence, duration of diabetes mellitus, history of macrovascular diseases, smoking habit, alcohol drinking habit, body mass index, hemoglobin A1c, total cholesterol, log-transformed triglyceride, systolic BP, eGFR, log-transformed urine albumin-creatinine ratio, randomized BP-lowering intervention, and randomized glucose control intervention (n=9190). 95% CI, 95% confidence interval; HR, hazard ratio.