GLUCOSE AND INSULIN LEVELS DURING DIURETIC THERAPY IN HYPERTENSIVE MEN

We investigated serum glucose and insulin levels resulting from thiazide or thiazide-like diuretic administration and determined whether they were associated with serum or intracellular potassium or magnesium values. We also explored the role of obesity both alone and with thiazides on serum insulin and glucose. Hypertensive men were withdrawn from diuretics and repleted with oral potassium and magnesium and then randomized to 2 months of treatment with (1) hydrochlorothiazide, (2) hydrochlorothiazide with oral potassium, (3) hydrochlorothiazide with oral potassium and magnesium, (4) hydrochlorothiazide and triamterene, (5) chlorthalidone, or (6) placebo. Serum was available from 202 participants for insulin and glucose determinations. Mean fasting serum glucose and insulin did not change significantly after 2 months of randomized therapy with the exception of participants randomized to chlorthalidone, who had significant increases in both serum insulin and glucose (P<.05 and P<.01, respectively). As body mass index increased, there was a corresponding increase in serum insulin and to a lesser degree in serum glucose. Also, as body mass index increased, participants taking hydrochlorothiazide had a corresponding increase of serum insulin (P<.05). After treatment, intracellular potassium and magnesium were both associated with higher serum insulin (P<.001 for each), and serum potassium was associated with higher and serum magnesium with lower serum glucose (P<.01 for each). In most hypertensive men, treatment with 50 mg chlorthalidone increases glucose and insulin levels, whereas administration of 50 mg hydrochlorothiazide, with or without potassium and/or magnesium conserving strategies, does not. Obesity has a deleterious effect on insulin metabolism both in hypertensive men not taking diuretics as well as in those receiving hydrochlorothiazide.