Prevalence of Electrolyte Impairments Among Outpatient Elderly Subjects

Abstract

Objective: To determine the prevalence of different electrolyte imbalances in a cohort of elderly subjects aged ≥65 years, and evaluate associations between each electrolyte imbalance and functional dependence.

Methods: We reviewed medical records of consecutive outpatient elderly subjects. Frequency of hyponatremia (serum sodium of 145 mmol/L), hypokalemia (serum potassium of 5.3 mEq/L), hypocalcemia (serum calcium of 10.5 g/dL), hypophosphatemia (serum phosphorus of 4.5 mg/ dL), hypomagnesemia (serum magnesium of 2.3 mg/dL) were assessed. Associations between each electrolyte disorder and Barthel and Lawton-Brody activities of daily living (BADL and IADL) were analyzed.

Results: Among the 464 subjects, hyponatremia (11.2%) hypomagnesemia (9.1%) and hypermagnesemia (8.8%) were the most common disorders. Patients with one electrolyte imbalance constituted 30.2% (140 patients) of the cohort, while 44 (9.5%) had two, and 7 (1.5%) patients had ≥2 electrolyte imbalances, concurrently. Calcium, phosphorus, and magnesium disorders were more common among subjects who were 80 years of age or more, compared to those aged 65-79 years, while the frequency of potassium disorders was lower in the former group. Hyponatremia and hypocalcemia were associated with functional dependence based on BADL and IADL scores. Patients with multiple electrolyte abnormalities had a higher risk of functional dependence.

Conclusion: Hypomagnesemia was as common as hyponatremia, especially among patients with an age of 80 years or more. Hyponatremia and hypocalcemia appeared to be associated with functional dependence. The higher number of electrolyte abnormality the higher risk of functional dependence. Our results should be confirmed by studies with larger sample sizes.