The minimum clinically important improvement in the incremental shuttle walk test following cardiac rehabilitation

Eur J Prev Cardiol. 2015 Aug;22(8):972-8. doi: 10.1177/2047487314540840. Epub 2014 Jun 23.


Background: The aim was to establish the minimum clinically important difference (MCID) in the incremental shuttle walk test (ISWT) following cardiac rehabilitation.

Design: This was a service evaluation, utilising anchor- and distribution-based methods.

Methods: Two hundred and twenty patients performed an ISWT following a six-week cardiac rehabilitation programme comprising supervised aerobic exercise, secondary prevention education and a home exercise programme.

Primary outcome: Patient perception of change in ISWT distance following cardiac rehabilitation. After completing cardiac rehabilitation, subjects were asked to identify, from a five-point Likert scale, their perceived change in exercise performance (range: from 'better' to 'worse'). Two distribution-based methods were also employed (standard deviation (SD) and effect size). The agreement between all measures was observed.

Results: Mean (SD) age was 65.0 (10.5) years, body mass index 28.4 (5.1), 170 male. The baseline ISWT was 390.8 (173.1) metres (m), which increased to 456.0 (186.7) m (mean change 65.2 (95% confidence interval 55.4-74.9) m after cardiac rehabilitation (p < 0.001)). In those rating their exercise tolerance as 'slightly better', the mean improvement was 70.0 (95% confidence interval 51.5-88.5) m. The SD method yielded a minimum clinically important difference value of 36.65 m and the effect size for the change was 0.38. The agreement between the patients' perception of change and distribution-based methods was poor.

Conclusions: The minimum clinically important difference for the ISWT following cardiac rehabilitation is 70 m. This patient-reported value is a more sensitive measure and has poor agreement with distribution-based estimates. This value may help clinicians interpret ISWT change in patients, help researchers estimate sample size and aid comparison between studies, when the ISWT is the primary outcome.

Keywords: Rehabilitation; exercise; exercise test; outcome assessment; walking.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Exercise Test / methods*
  • Exercise Therapy / methods*
  • Exercise Tolerance*
  • Female
  • Health Knowledge, Attitudes, Practice
  • Heart Diseases / diagnosis
  • Heart Diseases / physiopathology
  • Heart Diseases / psychology
  • Heart Diseases / rehabilitation*
  • Home Care Services*
  • Humans
  • Male
  • Middle Aged
  • Patient Education as Topic*
  • Predictive Value of Tests
  • Recovery of Function
  • Reproducibility of Results
  • Secondary Prevention / methods*
  • Time Factors
  • Treatment Outcome
  • Walking*