Associations between malnutrition and dehydration among older adults: A cross-sectional observational study.

Background: There is debate as to the association between dehydration and malnutrition. Thus, this study aimed to investigate the correlation between dehydration and malnutrition and their impact on geriatric syndromes.

Methods: This cross-sectional study included older adults (≥60 years) who attended one outpatient geriatric clinic. Malnutrition was defined according to the Mini Nutritional Assessment (MNA) score (<17), and dehydration was based on a single calculation method (plasma osmolarity [Posm] > 295 mmol/L).

Results: Among the 1409 patients studied, the prevalence of malnutrition and dehydration was 19% and 33%, respectively. The rate of malnutrition in the setting of dehydration was 18%, and the rate of dehydration in patients with malnutrition was 30% (P > 0.05). Polypharmacy, hypertension, diabetes mellitus, and higher body mass index (BMI) were associated solely with dehydration, whereas older age, a lower level of education, depression, and lower BMI were associated solely with malnutrition. Among patients with dehydration, there was a significant negative correlation between the MNA and Posm (P < 0.001, r = -0.20). Inversely, among patients without dehydration, the correlation was positive and significant (P < 0.001, r = 0.14).

Conclusion: A negative correlation was found between the MNA score and Posm in patients with dehydration, whereas the correlation is positive among patients without dehydration. This inverse relationship between the MNA score and Posm in patients with different levels of hydration is one potential reason for the lack of a significant correlation between malnutrition and dehydration in previously reported studies. Different risk factors of malnutrition may predominate in settings of dehydration vs no dehydration.