A NEW study has found that patients who develop hyponatremia after starting thiazide diuretics for hypertension have nearly twice the risk of death compared to those who maintain normal sodium levels. The research analysed data from over 93 million patients and highlights a significant safety concern for one of the most commonly prescribed classes of blood pressure medications.
Thiazide diuretics are widely used to manage hypertension, with an estimated 42 million patients in the U.S. alone taking them. However, these drugs can lead to hyponatremia, low sodium levels in the blood, which has long been recognized as a common side effect. Until now, its direct impact on mortality had not been well understood.
Researchers conducted a retrospective cohort study using electronic medical records from the TriNetX health research network. They examined adults aged 40 to 90 who were prescribed thiazide diuretics between 2010 and 2021. The study included 22,057 patients who developed hyponatremia (serum sodium ≤135 mmol/L within six months of starting treatment) and a control group of 234,466 patients who maintained normal sodium levels. After propensity score matching, both cohorts included 22,052 patients.
The results showed that the hyponatremia group had a significantly higher risk of death, with a hazard ratio of 1.96 (95% CI, 1.72-2.28; P<0.001). Patients in this group were also more likely to develop serious complications, including sepsis, pneumonia, urinary tract infections, cellulitis, myocardial infarction, stroke, congestive heart failure, ataxia, falls, and hip fractures.
Despite the study’s retrospective design, the findings raise concerns about the safety of thiazide diuretics in certain patients. The authors suggest that clinicians should closely monitor sodium levels in patients starting these medications to mitigate the risk of life-threatening complications.
Aleksandra Zurowska, EMJ
Reference
Achinger S et al. Thiazide-Associated Hyponatremia and Mortality Risk: A Cohort Study. Kidney Medicine. 2025;7(2):100941.
