Background: QMVC, a measure of isometric quadriceps strength, is responsive to PR but studies that have estimated the MID have been limited by small sample size.
Aim: To estimate the MID of QMVC following PR in COPD
Methods: Core PR outcomes and QMVC were measured before and after PR in 520 patients. Distribution (0.5xSD, standard error of measurement, minimal detectable change at 95% confidence) and anchor-based methods (mean change in QMVC in those reporting feeling ?A little better? in response to ?How much better do you feel following PR??) were used to estimate the MID.
Results: Baseline and response to PR data are in table 1. Following PR there were significant improvements in core PR outcomes and QMVC (mean (95%CI) change 2.0 (1.5 to 2.5)kg). Following PR, 476 (92.1%) of participants reported feeling ?a little? or ?much better?. The mean (range) MID was 2.8 (1.1 to 5.1)kg.
Conclusion: The mean MID estimate of QMVC following PR is 2.8kg
Table 1: Baseline characteristics and response to PR
| Variable | Baseline characteristics | Response to PR | p-value |
| Age (years) | 70 (8) | - | - |
| Sex (Male: n (%)) | 319 (61.3) | - | - |
| FEV1 (% predicted) | 51 (21) | - | - |
| BMI (kg/m2) | 27.6 (5.9) | - | - |
| MRC | 3 (1) | -1 (-1 to -1) | <0.001 |
| QMVC (kg) | 27.0 (10.2) | 2.0 (1.5 to 2.5) | <0.001 |
| ISW (m) | 250 (140, 360) | 50 (20, 90) | <0.01 |
| CRQ-Total | 77.8 (21.2) | 15.0 (13.4 to 16.6) | <0.001 |