Abstract
The Duke Activity Status Index (DASI) was developed as a simple tool of assessment of functional status for people with congestive heart failure (CHF)and correlated well with VO2max derived from cycle ergonometry and 6-minute walk distance in patients with COPD. Peak oxygen uptake correlates well with the Incremental Shuttle Walk Test (ISWT) which is commonly used to prescribe exercise in pulmonary rehabilitation. The aim was to establish whether VO2max predicted by the DASI compares well with that predicted by the ISWT and therefore whether the DASI could be used to support prescription of a training programme.
153 COPD patients (75 male; mean (SD) Age 70 (9.36)yrs; FEV1 1.34 (0.57)l; BMI 28.36 (6.75)) completed the DASI and the ISWT. Mean VO2max predicted from the DASI was 17.69 ml/min/kg and 10.03ml/min/kg from the ISWT, a significant difference of 7.67 (95%CI= 7.0-8.32)p<0.001. A Bland and Altman plot shows that there is poor agreement between the 2 measures (Fig1). There was moderate correlation between VO2max predicted by the DASI and ISWT (r=0.55,p<0.001).
Although there is a correlation between the DASI and the ISWT, poor agreement indicates that the measures cannot be used interchangeably and that the DASI cannot be used to prescribe a training programme for individuals with COPD.
- © 2011 ERS