Combination of Thiazide-Type Diuretic and Beta-Blocker may
Cause Diabetes
Clinical Question: In patients with hypertension is it safe to
combine thiazide-type diuretic and beta-blocker?
Bottom Line: Studies suggest that the routine combined use of a
thiazide with a beta-blocker should be questioned in the early
management of hypertension, particularly in patients who are at
increased risk of developing new-onset diabetes. In such
patients, the increased risk of developing diabetes may exceed
the benefit of blood pressure lowering.
Reference: J Hypertens. 2005 Oct;23(10):1777-1781
Study Design: Retrieve randomized control trials and
meta-analysis
Synopsis: Recently published trials addressing the
pharmacological management of hypertension have reported an
increase in new-onset diabetes mellitus when comparing certain
older and newer treatment regimens. Thiazide-type diuretics
(thiazides) and beta-blockers have been individually implicated,
but these drugs are frequently combined, and the magnitude of
risk associated with their combined use has not been quantified.
So randomized control trials were retrieved that: (i) featured
stepped treatment to manage hypertension; (ii) compared initial
treatment using a thiazide or beta-blocker (older drug) with an
angiotensin-converting enzyme inhibitor, angiotensin receptor
blocker or calcium antagonist (newer drug); (iii) assessed
cardiovascular outcomes; (iv) reported new-onset diabetes; and
(v) provided at least 1-year follow-up. A meta-analysis of
available trials indicated that patients exposed to treatment
regimens combining thiazides and beta-blockers are at greater
risk of developing diabetes than regimens avoiding this
combination of drugs (risk ratio for alternative therapy 0.81,
95% confidence interval 0.77-0.86). Current data cannot inform
reliably about the risks associated with individual older drugs
because of similar overall exposures in patients starting on
newer and older drugs.