According to a recent OHDSI paper, chlorthalidone, the guideline-recommended diuretic for lowering blood pressure, causes more serious side effects than hydrochlorothiazide, a similarly effective diuretic. The findings, published in JAMA Internal Medicine, contrast with current treatment guidelines recommending chlorthalidone over hydrochlorothiazide.
The results were generated by the Large-Scale Evidence Generation and Evaluation in a Network of Databases (LEGEND) Hypertension study, a method for analysing data in millions of electronic health records around the world developed by the Observational Health Data Sciences and Informatics (OHDSI) network, which has a central coordinating center at Columbia University.
This paper is the second paper resulting from the data of the LEGEND study. The first publication, published in The Lancet, described that thiazide diuretics were more effective and caused fewer side effects than ACE inhibitors when used as first-line antihypertensive drugs.
In the current paper, the researchers added that chlorthalidone and hydrochlorothiazide were similarly effective in preventing heart attack, hospitalization for heart failure, and stroke. However, patients treated with chlorthalidone had a significantly higher risk of side effects, including hypokalaemia, which can lead to abnormal heart rhythms; hyponatremia (low sodium), which can cause confusion; kidney failure; and type 2 diabetes.
Be sure to check out the OHDSI website to read the full report on this study.
You can also find an introduction to the LEGEND study on the OHDSI YouTube channel.