A SPECIFIC ACTIVITY QUESTIONNAIRE TO MEASURE THE FUNCTIONAL-CAPACITY OF CARDIAC PATIENTS

Exercise testing is often performed in persons with cardiac disease to measure their functional capacity. Physical activity questionnaires a ssessing functional capacity have been used as a low-cost and convenie nt alternative to exercise testing, but have not been well validated a gainst measured oxygen consumption in a cardiac population. This study assesses the ability of a simple, 13-item, self-administered activity questionnaire, known as the Specific Activity Questionnaire (SAQ), to measure functional capacity prospectively in a large sample of cardia c patients. Ninety-seven consecutive cardiac out-patients (85 men and 12 women aged 59 +/- 10 years [mean +/- SD]) completed the SAQ before an elective symptom-limited treadmill test. Subjects returned within 1 0 days to repeat the treadmill test, following the same protocol, with the additional measurement of peak oxygen consumption, VO2 (ml . kg(- 1) . min(-1)), using open circuit spirometry. The SAQ score was signif icantly related to measured peak VO2 (r = 0.57, p < 0.001). Stepwise m ultiple linear regression analysis found that the addition of patient age, height, and body weight to SAQ score improved the measurement of peak VO2, accounting for 51% of the sample variance (R = 0.71, p < 0.0 01). Peak VO2 was obtained from the following regression formula: VO2 = (2.36)SAQ + (0.35)HEIGHT - (0.19)AGE -(0.16)BODY WEIGHT - 33.89; SEE 6.43. Thus SAQ, a simple 13-item self-administered activity questionn aire, is able to provide a moderately good measure of functional capac ity in cardiac patients and may be a useful tool in studies of the car diac population when formal exercise testing is impractical or unecono mical.