The incidence of diuretic-induced hypokalemia in two distinct clinic settings.

We studied the incidence of diuretic-induced hypokalemia (DIH) in two diuretic-treated hypertensive populations. Thirty-seven patients with mild hypertension were treated with HCTZ and monitored over 6 months. Group 1 (21 patients) was treated with 25 mg HCTZ q.d. in a public hypertension clinic. Group 2 (16 patients) was treated with 50 mg HCTZ q.d. in a private-practice setting. Group 1 was predominantly nonwhite (76% vs. 31% [p less than 0.002]). Baseline serum potassium levels were lower in group 1 (3.93 vs. 4.42 mEq/L [p less than 0.001]). Equivalent reductions in blood pressure and serum potassium were observed in both groups. Contrary to expectations, DIH (serum potassium less than 3.5 mEq/L) developed in 52% of group 1 and 19% of group 2 (p = 0.037). Black females were especially at risk for DIH. The higher incidence of DIH in group 1 appears to be related to lower baseline serum potassium levels.