Limb muscle size and contractile function in adults with cystic fibrosis: A systematic review and meta-analysis

• Published in: Journal of cystic fibrosis Vol. 20; no. 5; pp. e53 - e62
• Main Authors: Wu, Kenneth, Mendes, Polyana L., Sykes, Jenna, Stephenson, Anne L., Mathur, Sunita
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-09-2021
• Subjects: Adult; Cystic fibrosis; Cystic Fibrosis - physiopathology; Hand Strength - physiology; Humans; Lower Extremity - physiopathology; Muscle Contraction - physiology; Muscle Strength - physiology; Muscle weakness; Muscle, Skeletal - physiopathology; Muscular atrophy; Respiratory Function Tests; Sex Factors; Skeletal muscle; Muscle weakness; FVC; ADLs; Adult; Cystic fibrosis; FEV1; SMD; Muscular atrophy; Skeletal muscle; CFTR; BMI; COPD
• ISSN: 1569-1993; 1873-5010
• DOI: 10.1016/j.jcf.2021.02.010

•Adults with CF have smaller thigh muscles, compared to healthy controls.•Adults with CF have lower handgrip strength than healthy controls.•A subgroup of adults with CF has lower quadriceps strength than healthy controls.•Lower handgrip strength is associated with lower lung function in adults with CF.•Females with CF has lower handgrip strength than males with CF.
There is conflicting evidence regarding the presence of limb muscle impairments in adults with cystic fibrosis (CF), and the factors associated with these muscle impairments. The objectives of this study were to compare limb muscle size and function between adults with CF and healthy controls; and to examine their associations with demographic and clinical variables in adults with CF.
The systematic review was performed using PRISMA guidelines. Studies were included if they measured any aspect of limb muscle size or function in adults with CF. Meta-analyses were performed to compare muscle variables between CF and healthy controls; and to examine their associations with demographic and clinical variables.
Twenty-eight studies were included, with 747 adults with CF. The meta-analyses showed that adults with CF have smaller thigh muscles [standardized mean difference (SMD) = 0.57, p<.0011, I2=0%], and lower handgrip strength (SMD = 0.89, p=.0034, I2=74.03%), which was weakly correlated with forced expiratory volume in one second (FEV1) (r=0.24, p=.035, I2=0%) and lower in females with CF (SMD = 2.05, p<.0001, I2=0%). There is no significant difference between adults with CF and controls in knee extensor strength (SMD = 0.25, p=.095, I2=42.79%).
Leg muscle atrophy and lower handgrip strength were noted. There may be a subgroup of adults with CF with knee extensor (quadriceps) weakness. Future studies are needed to better understand muscle impairments in people with CF; to explore the factors that can predict these muscle impairments; and to investigate their clinical significance in people with CF.