Relationship between lung function and Modified Shuttle Test performance in adult patients with cystic fibrosis: a cross-sectional, retrospective study

• Published in: Physiotherapy Vol. 102; no. 2; pp. 184 - 188
• Main Authors: Doeleman, W.R, Takken, T, Bronsveld, I, Hulzebos, E.H.J
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-06-2016
• Subjects: Adolescent; Adult; Cross-Sectional Studies; Cystic fibrosis; Cystic Fibrosis - physiopathology; Exercise; Exercise Test; Exercise Tolerance - physiology; Female; Forced Expiratory Volume - physiology; Humans; Male; Middle Aged; Modified Shuttle Test; Physical Medicine and Rehabilitation; Respiratory Function Tests; Retrospective Studies; Young Adult; Cystic fibrosis; Modified Shuttle Test; Exercise; Exercise test
• ISSN: 0031-9406; 1873-1465
• DOI: 10.1016/j.physio.2015.10.015

Abstract Objectives To investigate the relationship between lung function and exercise capacity in adults with cystic fibrosis (CF), and to develop a CF-specific equation to predict Modified Shuttle Test (MST) performance from baseline data. Design Cross-sectional, retrospective study. Setting Adult CF centre. Participants One hundred and twenty-seven patients with CF [61 male; mean age 25 years (range 17 to 52 years), mean forced expiratory volume in 1 second (FEV1 ) 56% predicted (range 15 to 124%)]. Main outcome measures MST and FEV1. Results Overall, a moderate-to-good relationship was found between lung function and MST performance (walking distance vs FEV1 % predicted: r = 0.64, P = 0.01). This relationship between FEV1 and MST shows an obvious threshold at an FEV1 of 67% predicted. Above this threshold, no significant association was observed between FEV1 and MST performance. However, a strong relationship (MST vs FEV1 % predicted: r ≥ 0.74, P < 0.01 for men and r = 0.79, P < 0.01 for women) was found below an FEV1 of 67% predicted. Conclusions This study suggests that a strong association exists between lung function (FEV1 % predicted) and MST (walking distance) in adult patients with moderate-to-severe CF (FEV1 < 67% predicted). A reference equation for MST performance was developed for those patients with FEV1 ≤67% predicted, providing a tool to make an a-priori prediction of MST walking distance.