Probable Respiratory Sarcopenia Decreases Activities of Daily Living in Older Patients Hospitalized with Respiratory Diseases: A Cross-sectional Study

ABSTRACT Objectives: Respiratory sarcopenia is characterized by low respiratory muscle mass and respiratory muscle strength, but its impact on activities of daily living (ADL) remains unknown. We aimed to investigate the association between respiratory sarcopenia and decreased ADL. Methods: This retrospective cross-sectional study included older inpatients (≥65 years old) with respiratory diseases who underwent rehabilitation. Because the evaluation of respiratory muscle mass is challenging, probable respiratory sarcopenia was defined according to low appendicular skeletal muscle index (<7 kg/m2 for men, <5.7 kg/m2 for women) and peak expiratory flow rate (<4.4 L/s for men, <3.21 L/s for women). ADL was assessed on the first day of rehabilitation using the baseline Barthel Index (BI). Results: Of 111 inpatients (median age 75 years; 57 women), 13 (11.7%) had probable respiratory sarcopenia. Forty-five patients (40.5%) had sarcopenia and 12 of these had probable respiratory sarcopenia. Pulmonary functions (Forced Vital Capacity and expiratory volume in 1 s) were significantly lower in patients with probable respiratory sarcopenia than those without. Spearman’s rank coefficient analysis showed probable respiratory sarcopenia did not significantly correlate with age, phase angle, Charlson Comorbidity Index (CCI), or hemoglobin (Hb). Multivariate linear regression analysis with baseline BI revealed probable respiratory sarcopenia (β −0.279 and P=0.004) was the significant factor after adjusting for age, sex, body mass index, chronic obstructive pulmonary disease, CCI, and Hb. Conclusions: Probable respiratory sarcopenia was independently associated with decreased ADL in patients aged 65 years and older who were hospitalized with respiratory diseases.