Feasibility of the A-STEP for the assessment of exercise capacity in people with cystic fibrosis

Pediatr Pulmonol. 2022 Oct;57(10):2524-2532. doi: 10.1002/ppul.26069. Epub 2022 Jul 18.

Abstract

Objectives: To evaluate feasibility of the Alfred Step Test Exercise Protocol (A-STEP) for the assessment of exercise capacity in adults and children with cystic fibrosis (CF); in adults to test whether demographics and/or lung function correlated with exercise capacity.

Methods: Adults and children with stable CF from two centres completed the A-STEP (a recently developed incremental maximal-effort step test). Feasibility was evaluated by: usefulness for exercise capacity assessment (measures of exercise capacity were: level reached, exercise-induced desaturation, and achievement of at least one maximal effort criteria); safety; operational factors; time to complete; floor and/or ceiling effects. We used multiple linear regression to test whether demographics and/or lung function correlated with exercise capacity.

Results: A total of 49 participants: 38 adults (18 male), percent predicted (pp) forced expiration in one second (FEV1 ) 29-109, aged 22-48 years and 11 children (6 male), ppFEV1 68-107, aged 10-15 years were included. Levels reached (mean (SD) [range]) were 10.2 (2.4) [6-15] (adults), 10.1 (2.5) [7-14] (children); desaturation (change between baseline and peak-exercise SpO2 ): was 8.4 (3.8 [0-15]% (adults), 2.0 (2.0) [0-7]% (children). A total of 8 (21%) adults and no children desaturated <90% SpO2 . At least one criterion for maximal effort was reached by 33 (84%) adults and 10 (91%) children. There were no adverse events. The A-STEP was straightforward to use and carried out by one operator. A total of 26 (68.4%) adults and 7 (63.6%) children completed the test within the recommended 8-12 min. All participants completed a minimum of 6 levels, and completed the test before the final 16th level. In adults, ppFEV1 and ppFVC correlated with the level reached (r = 0.55; p = <0.001 and r = 0.66, p = <0.0001) and desaturation (r = 0.55, p = <0.001 and r = 0.45, p = <0.005).

Conclusion: In adults and children with stable CF, the A-STEP was feasible, safe, and operationally easy to use for the assessment of exercise capacity, without floor or ceiling effects. In adults, lung function correlated with exercise capacity.

Keywords: exercise testing; incremental test; maximal effort; maximal test; oxygen desaturation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cystic Fibrosis* / diagnosis
  • Exercise Test / methods
  • Exercise Tolerance
  • Feasibility Studies
  • Humans
  • Male
  • Respiratory Function Tests