Absence of established reference values limits application of quadriceps maximal voluntary contraction (QMVC) measurement. The impact of muscle mass inclusion in predictions is unclear. Prediction equations encompassing gender, age and size with (FFM+) and without (FFM−), derived in healthy adults (n=175), are presented and compared in two COPD cohorts recruited from primary care (COPD-PC, n=112) and a complex care COPD clinic (COPD-CC, n=189). Explained variance was comparable between the prediction models (R2: FFM+: 0.59, FFM−: 0.60) as were per cent predictions in COPD-PC (88.8%, 88.3%). However, fat-free mass inclusion reduced the prevalence of weakness in COPD, particularly in COPD-CC where 11.9% fewer were deemed weak.
- Muscle strength
- Chronic obstructive pulmonary disease
- Quadriceps maximal voluntary contraction
- Fat-free mass
- Prediction equation
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Contributors RET and MCS developed the concept of the study and wrote the manuscript. Others contributed to the final version. RET, ESP, DWE, NJG and MCS were involved in the study design and data analysis. BDJ made additional contributions to the data analysis. DWE, RAE, NJG, AK, MWO, LBS, SJS, MCS and NT were also involved in the data acquisition and all authors have provided approval of the final version to be published.
Competing interests None declared.
Ethics approval The cohorts studied had the relevent NHS REC approvals: 13-EM-0389, 13/EM/0287.
Provenance and peer review Not commissioned; externally peer reviewed.
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