Appendicular Skeletal Muscle Mass Correlates with Patient-Reported Outcomes and Physical Performance in Patients with Idiopathic Pulmonary Fibrosis

Abstract

Idiopathic pulmonary fibrosis (IPF), an incurable lung disease of unknown cause, often presents with losses of skeletal muscle mass. IPF requires comprehensive care, but it has not been investigated which skeletal muscle mass index reflects holistic management factors: pulmonary function, patient-reported outcomes (PROs), and physical performance. We compared three representative indices of skeletal muscle mass with holistic management factors in IPF patients. Twenty-seven mild to severe IPF patients (21 male) with the mean age of 76.1 ± 5.9 years were enrolled. The three indices were appendicular skeletal muscle mass index (ASMI), cross-sectional area of pectoralis major (PM CSA), and cross-sectional area of erector spinae muscles (ESM CSA). ASMI is considered as a gold standard for sarcopenia assessment, while PM CSA and ESM CSA are frequently used in IPF. As PROs, we assessed breathlessness with the modified Medical Research Council dyspnea scale (mMRC), symptoms with the chronic obstructive pulmonary disease assessment test (CAT), and health-related quality of life with St. George's Respiratory Questionnaire (SGRQ). For physical performance, peripheral muscle strength and 6-min walk distance (6MWD) were investigated. In this cross-sectional study, ASMI showed the greatest number of significantly correlated indices, such as pulmonary function, peripheral muscle strength, 6MWD, mMRC, and SGRQ. PM CSA showed the next greatest number of correlations, with peripheral muscle strength, 6MWD, and mMRC, whereas ESM CSA showed no significant correlations with any index. Thus, ASMI correlated with both PROs and physical performance, and PM CSA correlated mainly with physical performance. In conclusion, assessing ASMI is helpful for the comprehensive care of patients with IPF.

Frequency and impact on clinical outcomes of sarcopenia in patients with idiopathic pulmonary fibrosis

“…Regarding interstitial lung disease (ILD), it is reported that sarcopenia was identified in 32.1% of Japanese patients with ILD. 19 In patients with IPF, the reported muscle assessments were the fat-free mass index, 20 ASMI, 21 and cross-sectional area of the erector spinae muscles. [22][23][24][25][26] A lower skeletal muscle mass is associated with lower quality of life and worse prognosis.…”

Urinary titin N-fragment as a predictor of decreased skeletal muscle mass in patients with interstitial lung diseases

“…Furthermore, the PM CSA was correlated with mortality in ever smokers 31 and the total energy expenditure and physical activity level in patients with COPD 32 . In patients with ILD, lower PM CSA was associated with the skeletal mass index, quadriceps isometric maximal voluntary contraction, and the indicators of ILD severity 8,14,33 , besides being a poor prognostic factor 14 .…”

Associations of Muscle Density and Area With Coronary Artery Plaque and Physical Function

“…Among women and men with and without HIV, we found that both thigh and trunk muscle density and area were associated with measures of physical function. 14,15,48 Although upper body muscle area would conceivably be more directly associated with upper body measures of strength or function, other studies have found associations between pectoralis muscle area and lower extremity measures, including 30 seconds sit-to-stand 49 and 6-minute walk distance 50 ; thus, some authors have proposed that upper body lean mass may serve as a surrogate for whole-body lean mass. 51 Data on associations with muscle density and function are scarce.…”