Current Trends in Prevalence and Etiologic Factors Responsible for Hyponatremia in Hospitalized Patients

Abstract

Purpose: Hyponatremia is the most common electrolyte disorder seen in hospitalized patients. The prevalence has been reported to be 5-30% depending on the clinical setting. The aim of this study was to determine the prevalence and etiologies of hyponatremia in patients now receiving care in our hospital. Methods: We collected data on two separate days one month apart to evaluate the current prevalence and etiology of hyponatremia in patients in our hospital. We defined hyponatremia as a serum sodium level less than 135 mEq/L. We also divided hyponatremia patients into 2 groups depending on age to evaluate possible differences in etiology. Results: We found that 41 out of 879 patients (4.7%) were hyponatremic. Eighty-five percent of patient’s exhibited a serum sodium of 130-134 mEq/L. the majority of cases of hyponatremia were associated with medication use (34.1%). Other associated etiologies were hypovolemia, malignancy, lung disorders, congestive heart failure (CHF), patients on dialysis and postoperative patients. Twelve patients had data consistent with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). In terms of age, 56% of patients were more than 65 years of age. Patients receiving diuretics was a frequent etiology in older individuals, while dialysis therapy was common in younger patients. Conclusion: Our findings suggest that the current prevalence of hyponatremia is not as high as reported in some previous studies. In addition, the hyponatremia observed tends to be mild and current related conditions include patients on dialysis therapy. Medication use continues to be a common responsible factor.