Clinical and Genetic Factors for Thiazide-Induced Hyponatremia

What is it about?

We have identified the clinical and genetic factors for thiazide-Induced hyponatremia in a cohort of patients in Taiwan. A total of 48 patients admitted to the ward or to the emergency department due to severe thiazide-induced hyponatremia (Na<125 mmmol/L) were enrolled as the case group. Another 211 hypertensive patients with normal sodium levels after treatment with thiazide diuretics were selected as the control group. The patients with thiazide-induced hyponatremia were older (P<0.001), predominantly female (P=0.008), had a lower mean body mass index (BMI) (P<0.001), and more commonly used angiotensin II receptor antagonist (P<0.001) and spironolactone (P=0.007) compared with the control groups. Analysis with multivariate logistic regression revealed that age (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08–1.19, P<0.001), female gender (OR, 4.49; 95% CI, 1.54–13.11, P=0.006), BMI (OR, 0.80; 95% CI, 0.69–0.93, P=0.003), and KCNJ1 rs2509585 C/T or T/T polymorphisms (OR, 5.75; 95% CI, 1.25–26.45, P=0.03) were independent predictors for thiazide-induced hyponatremia. Accordingly, we found that older female patients with lower BMIs and KCNJ1 rs2509585 C/T or T/T polymorphisms were more likely to develop thiazide-induced hyponatremia.

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Why is it important?

Thiazide diuretics are commonly suggested as one of the first line antihypertensive treatment by almost all the hypertensive guidelines worldwide. It is particularly suggested for the treatment of hypertension in elderly patients. We found for the first time that older female patients with lower BMIs and KCNJ1 rs2509585 C/T or T/T polymorphisms were more likely to develop thiazide-induced hyponatremia. The findings may help to identify the high risk group of thiazide-induced hyponatremia as a severe side effect of thiazide treatment in clinical setting.

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