Correlation between Phase Angle and the Number of Medications in Older Inpatients: A Cross-Sectional Study

Muscle weakness in older adults elevates mortality risk and impairs quality of life, with the phase angle (PhA) indicating cellular health. Polypharmacy, common in geriatric care, could influence PhA. This investigates whether the number of medications and polypharmacy with PhA as a biomarker of muscle quality in older inpatients aged ≥65 and determines the extent to which multiple medications contribute to the risk of reduced muscle quality.

This retrospective cross-sectional study analyzed data from older inpatients requiring rehabilitation. PhA was measured using bioelectrical impedance analysis. The number of medications taken by each patient was recorded at admission. Polypharmacy was defined as the concurrent use of five or more medications at admission.

In this study of 517 hospitalized older adults (median age 75 years; 47.4% men), 178 patients (34.4%) were diagnosed with sarcopenia. Polypharmacy was present in 66% of patients. The median PhA was 4.9° in men and 4.3° in women. Multivariate linear regression analysis was performed separately for men and women. In men, PhA was negatively correlated with the number of medications (β=-0.104, p=0.041) and polypharmacy (β=-0.045, p=0.383). In women, PhA was negatively correlated with the number of medications (β=-0.119, p=0.026) and polypharmacy (β=-0.098, p=0.063). Analyses were adjusted for age, body mass index, sarcopenia, C-reactive protein, and hemoglobin levels.

The number of medications at admission negatively impacted PhA in older inpatients, highlighting the importance of reviewing prescribed drugs and their interactions.