Elevated hemoglobin A1c and low-density lipoprotein cholesterol levels in thiazide-treated diabetic patients.

Despite the well-known hyperglycemic effect of thiazide diuretics, these agents are often administered to diabetic patients. This study compared 89 insulin-treated diabetic patients receiving hydrochlorothiazide, 57 receiving furosemide, and 255 receiving no diuretic. Hemoglobin A1c level was 7.2 +/- 1.8 percent (mean +/- SD) with hydrochlorothiazide, significantly higher than the levels of 5.9 +/- 2.3 percent with furosemide and 6.4 +/- 2.0 percent with no diuretic. Low-density lipoprotein cholesterol level was 154 +/- 43 mg/dl with hydrochlorothiazide, but 134 +/- 42 mg/dl with furosemide and 130 +/- 42 mg/dl with no diuretic. Multivariate analysis showed that the associations remained significant after adjustment for age, sex, race, type and duration of diabetes, body mass index, blood pressure, serum potassium level, insulin dose, and treatment with other medications. These findings suggest that treatment with thiazide diuretics in the diabetic population may increase low-density lipoprotein cholesterol and hemoglobin A1c levels.