Clinical, Biochemical, and Outcome Profile of Hyponatremia in Geriatric and Non-Geriatric Individuals Admitted to a Tertiary Care Centre: A Prospective Cohort Study

Introduction: Hyponatremia is one of the most common electrolyte disturbances encountered in medical wards, occurring in up to 22% of hospitalised patients. Timely recognition and correction of hyponatremia in hospitalised patients may help decrease in-hospital mortality and symptom severity, reduce the need for intensive hospital care, decrease the duration of hospitalisation and associated costs, and improve the treatment of underlying co-morbid conditions and patient's quality of life. Aim: To compare the clinical presentation, aetiology, biochemical profile, management strategies, and outcomes of hyponatremia in geriatric and non-geriatric individuals admitted to a tertiary care centre.Materials and Methods: This prospective cohort study was conducted in the Department of General Medicine at Mahatma Gandhi Medical College and Research Institute, Pondicherry, India, from March 2021 to September 2022. A total of 166 subjects (83 geriatric and 83 non-geriatric patients) receiving inpatient services with hyponatremia were enrolled in the study by consecutive sampling. Patients over 18 years of age admitted to the Department of General Medicine with serum sodium levels below 135 mEq/L were included. Comparison of both the groups were done based on clinical presentation, laboratory values, co-morbidities, prescription drugs taken, aetiology, treatment given, and outcomes. For quantitative variables, mean, standard deviation, and independent t-tests were used, while percentages were used for qualitative variables.Results: The majority of subjects in the non-geriatric group belonged to the age group of 50-59 years, with a mean age of 50.7 years. In the geriatric group, most subjects were in the age group of 65-74 years, with a mean age of 74.5 years. The most common cause of hyponatremia in both groups was Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH), with 32 (38.6%) cases in the non-geriatric group and 27 (32.5%) cases in the geriatric group. This was followed by volume overload in the non-geriatric group, with 14 (16.9%) cases, and drug-induced hyponatremia in the geriatric group, with 22 (26.5%) cases. The most common drug causing hyponatremia was furosemide in both groups. In non-geriatric patients, the most common symptom was giddiness, with 28 (34.1%) cases, while in geriatric patients, it was nausea/vomiting, with 25 (30.1%) cases. Tolvaptan was the most common treatment used in both groups, with 12 (92.3%) of patients with mild hyponatremia receiving it in the non-geriatric group (p=0.042), and 46 (55.4%) patients in the geriatric group, with most of them having moderate hyponatremia (26, 86.7%, p<0.001).Conclusion: The results of the non-geriatric and geriatric groups were similar in terms of clinical presentation, biochemical parameters, management strategies, and outcome of hyponatremia. However, the aetiology of hyponatremia appeared to be different. The most common cause of hyponatremia was SIADH in both groups, followed by volume overload in the non-geriatric group and drug-induced hyponatremia in the geriatric group.