PT  - JOURNAL ARTICLE
AU  - Claire M. Nolan
AU  - Samantha S.C. Kon
AU  - Jane L. Canavan
AU  - Sarah E. Jones
AU  - Matthew Maddocks
AU  - Paul Cullinan
AU  - Toby M. Maher
AU  - William D.-C. Man
TI  - Preferential lower limb muscle weakness in idiopathic pulmonary fibrosis: Effects on exercise capacity
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P4492
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P4492.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P4492.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - BackgroundSkeletal muscle dysfunction is common in COPD patients and contributes to exercise intolerance. Less is known about skeletal muscle function and its impact on exercise capacity in those with idiopathic pulmonary fibrosis (IPF). This is of interest as skeletal muscle dysfunction is potentially amenable to treatment.AimTo compare upper and lower limb muscle strength in IPF patients; to determine whether muscle weakness contributes to exercise intolerance in this group.MethodHandgrip strength (HG) and isometric quadriceps maximum voluntary contraction (QMVC) were measured using a dynamometer (Jamar) and a strain gauge fitted to a specially designed chair in 61 IPF patients. HG and QMVC were normalised to healthy population values (Spruit et al 2013; Seymour et al 2010). Other measurements included spirometry, exercise capacity measured by incremental shuttle walk (ISW), health status measured by St. George's Respiratory Questionnaire (SGRQ) and respiratory disability measured by MRC dyspnoea scale.ResultBaseline characteristics were 38 men, mean(SD) age 70(11)years, BMI 28.8(5.9)kg/m2, Forced Vital Capacity (FVC) 65(22)%, MRC 3.2(1.0), SGRQ 52.4(15.7) and ISW 226(141)m. Mean (SD) HG and QMVC were 26.3(8.7)kg and 24.1(9.3)kg respectively. QMVC%pred was significantly lower than HG %predicted (mean (SD) 54(14)%, 84(20)%; p<0.0001). On univariate analysis, ISW was significantly associated with height, FVC%pred, MRC, HG%pred, SGRQ and QMVC%pred. On multiple regression, only QMVC%pred, MRC and height remained independent predictors of ISW.ConclusionThere is preferential weakness of the lower limb muscles in patients with IPF which contributes to exercise intolerance.