Combination of Thiazide-Type Diuretic and Beta-Blocker may Cause Diabetes

by Rodolfo T. Rafael,M.D.


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.
About the Author

A Certified Family Physician of the Philippine Academy of Family Physician and continue to complete the requirements for Continuing Medical Education in Family Practice. Also a member of the Philippine Medical Informatics Society, Philippine Occupational Health and Safety Inc., and Pangasinan Medical Society. Faculty Department of Physiology (Medicine) Lyseum- Northwestern University, Dagupan, Pangasinan, Faculty Medical Informatics Lyseu