Hyponatremia In Hospitalized Older Adults Is Associated With Polypharmacy, Longer Hospital Stay, And Higher Mortality

OBJECTIVE: To evaluate hyponatremia in older patients during hospital stay and determine its association with polypharmacy, length of hospital stay, and mortality. METHOD: This was an observational, analytical, cross-sectional study of patients aged 65 years and older during hospitalization. The first sodium sample requested by the physician was considered for analysis. Hyponatremia was classified according to severity as mild (130–135 mEq/L), moderate (125–129 mEq/L), or severe (< 125 mEq/L) and according to osmolarity as isotonic (275–295 mOsm/L), hypotonic (< 275 mOsm/L), or hypertonic (> 295 mOsm/L). The χ2 test and oneway analysis of variance followed by Tukey’s post hoc test were used to analyze length of hospital stay between the groups (normonatremia and mild, moderate, and severe hyponatremia). The χ2 test was also used to compare mortality between the groups. RESULTS: We included 174 patients, with a mean age of 74 (SD, 7; range, 65–95) years; 52.3% were men. Overall, 44.8% had normonatremia, 37.8% had mild hyponatremia, 9.2% had moderate hyponatremia, and 8.0% had severe hyponatremia. Increased hospital stay was observed in patients with hyponatremia, being longer in those with severe hyponatremia. Polypharmacy occurred in 39.3% of patients. Of patients with severe hyponatremia, 71.4% had polypharmacy (p = 0.01). CONCLUSIONS: Hospitalized older adults showed a high rate of hyponatremia and an important association with polypharmacy and prolonged hospital stay.