The prevalence of hypertension in the United States has grown dramatically in recent years. Thiazide diuretics have played a major role in the rising rate of blood pressure (BP) control. Accompanying this has been the appearance of adverse drug events, including hospitalizations associated with thiazide-associated hyponatremia (HTAH). Hyponatremia is a common yet often overlooked side effect of this drug class. Identification of HTAH risk factors may aid in creating strategies to prevent hospitalizations. This is a retrospective, case-controlled study of 10,805 patients (1802