Incident hyponatremia among skilled nursing facility residents: association with enteral feeding tube use and chronic comorbidities.

BACKGROUND

Hyponatremia has long been recognized as a common electrolyte abnormality among skilled nursing facility (SNF) residents. In the literature, hyponatremia is associated with increases in falls, cognitive impairment, hospitalization, and increased mortality. Although many medical conditions and medications contribute to hyponatremia risk, the role of enteral feeding tubes in this population has not been well defined in clinical practice. This study examined the association between enteral feeding tube use and incident hyponatremia and evaluated selected chronic conditions and medication exposures in SNF patients.

METHODS

We conducted a retrospective cohort study using secondary data from a suburban skilled nursing facility. Adults aged ≥ 18 years residing in the SNF with available laboratory data were included (n = 1,256). Exposures included presence of an enteral feeding tube at admission, selected chronic conditions, and high-risk medication exposures. The primary outcome was incident hyponatremia, defined as any corrected serum sodium value < 135 mEq/L occurring after admission. Relative risks were estimated using modified Poisson regression.

RESULTS

Incident hyponatremia occurred in 34.6% of residents. In adjusted models, enteral feeding tubes (aRR 2.42; 95% CI 1.84-3.19), chronic kidney disease (aRR 1.87; 95% CI 1.43-2.44), and Liver Disease (aRR 1.58; 95% CI 1.20-2.07) remained the significant independent predictors. Congestive Heart Failure, ethnicity, sex, age, and high-risk medication exposure were not significantly associated with risk at the predetermined alpha = 0.01, and no significant interactions were observed between CKD, CHF, and liver disease and enteral feeding tubes on incident hyponatremia.

CONCLUSIONS

Hyponatremia remains a common electrolyte abnormality among SNF residents. Enteral feeding tube use was strongly associated with increased cumulative risk of incident hyponatremia. Both CKD and liver disease also pose risk of incident hyponatremia. SNF residents with enteral feeding tubes may benefit from targeted monitoring and risk stratification in long-term care settings. Clinicians should be aware of these risks while ordering water flushing of enteral tubes and assess these patients regularly for hyponatremia.

CLINICAL TRIAL NUMBER: Not applicable.