Common diuretics may lower heart risk more than ACE inhibitors

A commonly prescribed type of water pill may be a better first choice for treating high blood pressure than ACE inhibitors, according to an analysis covering millions of patients.

The results call into question long-held assumptions about which medication should come first.

Thiazide diuretics help the body flush salt and water through urine, which lowers pressure in the blood vessels. ACE inhibitors work through a different mechanism, blocking a hormone pathway that narrows blood vessels.

Researchers at Columbia University reviewed health records from nearly five million people who were beginning treatment for high blood pressure. They compared outcomes among patients who started with different medication classes.

ACE inhibitors were often chosen as the first treatment, while thiazide diuretics were prescribed less often. The size of the database allowed the team to compare relatively uncommon outcomes across a very large group.

The analysis showed that patients who began with thiazide diuretics had fewer major cardiovascular events than those who started with ACE inhibitors. The original report described the difference as roughly 15% for serious outcomes.

The outcomes studied included heart attacks, heart failure and strokes. Because each of these can have severe consequences, even small differences between widely used treatments may matter at the population level.

The researchers also found more recorded side effects among patients taking ACE inhibitors. These included a dry cough, higher blood potassium levels and some kidney-related problems.

That does not mean ACE inhibitors are broadly unsafe or that diuretics should always be preferred. Both drug classes have well-established roles, and other medical conditions can affect which option is most suitable.

The study used existing health records rather than randomly assigning treatments. Differences between patients, prescribing choices and medical histories may have influenced the findings despite statistical adjustments.

Overall, the research suggests that the first blood pressure medication should be chosen with careful attention to both effectiveness and side effects. It does not prove that one pill is best for every person with hypertension.

Studies based on health records can reveal outcomes that are difficult to capture in smaller trials. They also mirror real-world prescribing patterns, including the medicines doctors tend to select for patients with different health backgrounds.

That strength also brings a limitation: the treatment a patient receives may be linked to their health before treatment begins. Statistical methods can reduce some of those differences, but they cannot eliminate every possible confounding factor.

The findings therefore support a closer look at thiazide diuretics as an initial option, rather than a blanket criticism of ACE inhibitors. Treatment comparisons are most useful when benefits, risks and patient differences are considered together.

If you are interested in this topic, please read articles about Eating more plant-based proteins can lower blood pressure, study finds, and Fruits and vegetables can lower blood pressure and protect heart and kidneys.

For more information, please see articles about What should know about high blood pressure drugs and their side effects, and Breakfast for better blood pressure: what to eat to keep your heart happy.