Thiazide plus potassium-sparing diuretics better than monotherapy in treating hypertension

Use of thiazides with potassium-sparing (PS) diuretics results in greater blood pressure (BP)-lowering efficacy, as well as reduces hypokalaemia and hyperglycaemia, compared with thiazides alone, reports a recent study.

A group of researchers conducted a systematic literature search in PubMed/Medline, Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scopus, and Lilacs of randomized controlled trials with 3 weeks to 1 year of follow-up. Two independent reviewers extracted the sample size, mean and standard deviation from baseline, follow-up and change from baseline values.

The effects of treatments were compared using pairwise random effect models and Bayesian network meta-analysis models. The risk of bias in each study was assessed using the Rob 1.0 tool.

Overall, 276 double-blind trials, including 58,807 participants (mean age 55 years, 45 percent women), met the eligibility criteria.

All treatments were more effective than placebo in reducing BP, with mean differences (MDs) of change from baseline ranging from ‒7.66 mm Hg for low-dose thiazide to ‒12.77 mm Hg for high-dose thiazide plus low-dose PS. Notably, high-dose thiazide alone or combined with PS was better than low-dose thiazide in lowering BP.

Using the surface under the cumulative ranking curve (SUCRA) estimates, the most effective treatment for lowering systolic BP was observed for high-dose thiazide plus low-dose PS (0.69), high-dose thiazide plus high-dose PS (0.65), and high-dose thiazide (0.54).

All treatment regimens, except low-dose thiazide plus low-dose PS, contributed to greater potassium reduction compared with placebo, as did high-dose thiazide when compared with other treatment and low-dose thiazide alone vs low-dose thiazide plus low-dose PS.

All active treatments, except high-dose thiazide plus high-dose PS, were associated with higher increases in uric acid when compared with placebo. Notably, PS agents reduced the increase of plasma glucose promoted by thiazides alone.

“These findings demonstrate that thiazide and PS diuretic combination is preferable to thiazide alone in treating hypertension,” the researchers said.