Measuring functional status of chronic coronary patients. Reliability, validity and responsiveness to clinical change of the reduced version of the Duke Activity Status Index (DASI)

Abstract

Aims: Health-related quality of life assessment may be useful for understanding the variability in functioning of patients with a similar level of clinical impairment. We assessed the reliability, validity and responsiveness to clinical change of a reduced version of the Duke Activity Status Index (DASI) in chronic coronary patients. Methods and results: The reduced version of the DASI, a measure of self-reported functional capacity, was administered twice to two groups of patients: 46 stable coronary heart disease outpatients were tested and re-tested 2 weeks after their initial visit; and 44 patients undergoing elective angioplasty for angina pectoris were evaluated the day before and one month after the procedure. The Canadian Cardiovascular Society (CCS) functional grade was assessed in all patients, and a treadmill exercise test was performed sequentially (before and after the procedure) in angioplasty patients. Cronbach's alpha reliability coefficients for reduced DASI scores were high (between 0.81 and 0.89). Correlations of the reduced DASI scores with CCS grade and exercise test duration were moderately high (r = -0.51 and r = 0.45, respectively). Improvement after angioplasty as assessed by the reduced DASI scores was important (effect size = 0.75, P < 0.001). Conclusion: The reduced DASI is reliable, valid and responsive to clinical changes. Health-related quality of life measures may be useful in monitoring coronary patients.