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Differential effect of β‐blocker therapy on insulin resistance as a function of insulin sensitizer use: results from GEMINI
Author(s) -
Fonseca V.,
Bakris G. L.,
Bell D. S. H.,
McGill J. B.,
Raskin P.,
Messerli F. H.,
Phillips R. A.,
Katholi R. E.,
Wright J. T.,
Waterhouse B.,
Lukas M. A.,
Anderson K. M.
Publication year - 2007
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1111/j.1464-5491.2007.02151.x
Subject(s) - medicine , metformin , carvedilol , metoprolol tartrate , metoprolol , insulin resistance , insulin , endocrinology , diabetes mellitus , heart failure
Aims To determine whether the beneficial effects of carvedilol on insulin resistance (IR) are affected by the concomitant use of insulin sensitizers [thiazolidinediones (TZDs) and metformin]. Methods Changes in HbA 1c and homeostasis model assessment‐insulin resistance (HOMA‐IR) were assessed over 5 months, comparing carvedilol with metoprolol tartrate according to insulin sensitizer (TZDs and metformin) use. Results In TZD/metformin users, carvedilol patients showed a 5.4% decrease [95% confidence interval (CI) −11.9, 1.6; P = 0.13] and metoprolol tartrate patients showed a 2.8% decrease (95% CI −8.5, 3.2; P = 0.35) in HOMA‐IR. The −2.6% difference between treatments was not significant (95% CI −10.7, 6.2; P = 0.55). In contrast, those not taking TZD/metformin experienced a 13.2% increase in HOMA‐IR on metoprolol tartrate (95% CI 3.2, 24.1; P < 0.01) and a 4.8% decrease in HOMA‐IR on carvedilol (95% CI −14.6, 6.0; P = 0.37), with a significant treatment difference of −15.9% favouring carvedilol (95% CI −26.6, −3.6; P = 0.01). There was no significant treatment interaction for the use of TZD/metformin and HbA 1c . A statistically significant treatment difference was observed for HbA 1c after 5 months favouring carvedilol after adjusting for insulin sensitizer use (−0.11%, 95% CI −0.214, −0.009; P = 0.03). Conclusions In patients with diabetes and hypertension not taking insulin sensitizers, the use of metoprolol tartrate resulted in a worsening of insulin resistance, an effect not seen with carvedilol. However, in TZD/metformin users the difference between the β‐blockers was not statistically significant.