Does response of RAS blockade on serum K+ levels influence its glycemic-mitigating response when combined with hydrochlorothiazide?

Abstract

The authors previously reported that addition of valsartan ameliorated the negative metabolic effects of hydrochlorothiazide in obese hypertensive patients through an enhanced postprandial insulin response. In this secondary analysis, the authors tested whether this enhanced insulin response to valsartan/hydrochlorothiazide was influenced by serum potassium levels, which were reduced to a lesser extent, when compared with amlodipine/hydrochlorothiazide. Results showed that the early insulin response with valsartan plus hydrochlorothiazide occurred regardless of serum potassium levels. Heightened insulin response was, however, not significantly different when patients with normal potassium (>3.9 mEq/L) at baseline and low potassium (≤3.9 mEq/L) at the end of the study were compared with the amlodipine/hydrochlorothiazide group. Despite the influence of serum potassium on insulin secretory response to a glucose challenge, the addition of valsartan maintained normoglycemia in patients given hydrochlorothiazide. Thus, the metabolic response to hydrochlorothiazide was improved with addition of valsartan through an enhanced insulin response that was not greatly affected by changes in potassium levels.

Trial registration: ClinicalTrials.gov NCT00439738.

© 2012 Wiley Periodicals, Inc.

Figures

Figure 1

Postprandial glucose (A, B, C) and insulin (D, E, F) after oral glucose tolerance test (OGTT) challenge at baseline and at the end of the study (EOS) in patients with baseline potassium (K+) >3.9 mEq/L and EOS K+ >3.9 mEq/L; baseline K+ >3.9 mEq/L and EOS K+ ≤3.9 mEq/L; and baseline K+ ≤3.9 mEq/L and EOS K+ >3.9 or ≤3.9 mEq/L, respectively. Aml indicates amlodipine; HCTZ, hydrochlorothiazide; Val, valsartan. Error bars represent standard error.

Figure 2

Mean change from baseline to end of the study (EOS) (week 16) in postprandial plasma glucose (A) and postprandial serum insulin (B) area under the curve (AUC) from 0 to 120 minutes (AUC0–120 min). Aml indicates amlodipine; HCTZ, hydrochlorothiazide; Val, valsartan. Error bars represent standard error.