STUDY OBJECTIVE: To determine whether changes in
serum glucose, serum
potassium, and plasma
insulin levels are
correlated in a cohort of
hypertensive patients. DESIGN: Prespecified
subgroup analysis of results from a prospective, multicenter,
randomized, open-label, parallel-group study. Setting. Primary care clinics at three tertiary care medical centers. PATIENTS: Community-based ambulatory population of 202 patients (age range 17-65 yrs) with a new diagnosis of
hypertension, untreated
hypertension, or known
hypertension, who were previously treated with fewer than three
antihypertensive drugs and had no evidence of
cardiovascular disease or
diabetes mellitus. Intervention.
Monotherapy with oral
hydrochlorothiazide 12.5 or 25 mg/day for 9 weeks. MEASUREMENTS AND MAIN RESULTS: Fasting
serum glucose, serum
potassium, and plasma
insulin levels were obtained at baseline (before
hydrochlorothiazide therapy was started) and after 9 weeks of therapy. Significant elevations were noted in fasting
serum glucose (
mean +/- SD 3.42 +/- 10.38 mg/dl, p<0.0001) and plasma
insulin (2.35 +/- 9.47 microU/ml, p<0.0001) levels, and a
significant reduction in serum
potassium level (0.30 +/- 0.44 mEq/L, p<0.0001) was noted. No significant
correlation was observed between changes in fasting
serum glucose and
potassium levels (r = 0.022, 95%
confidence interval (CI) -0.120-0.164, p=0.757) or between changes in serum
potassium and plasma
insulin levels (r = -0.112, 95% CI -0.256-0.037, p=0.140). Changes in
serum glucose levels did not differ significantly between patients maintaining serum
potassium levels of 4.0 mEq/L or greater and those with levels below 4.0 mEq/L. CONCLUSION: Changes in serum
potassium and
serum glucose levels were not
correlated in individuals receiving
hydrochlorothiazide monotherapy; thus maintenance of normal
potassium levels may not
attenuate the risk of
thiazide diuretic-induced
hyperglycemia.
