Background: In the original 32-item Asthma Quality of Life Questionnaire (A
QLQ), five activity questions are selected by patients themselves. However,
for long-term studies and large clinical trials, generic activities may be
more appropriate.
Methods: For the standardized version of the AQLQ, the AQLQ(S), we formulat
ed five genetic activities (strenuous exercise, moderate exercise, work-rel
ated activities, social activities, and sleep) to replace the five patient-
specific activities in the AQLQ. In a 9-week observational study, nle compa
red the AQLQ with the AQLQ(S) and examined their measurement properties. Fo
rty symptomatic adult asthma patients completed the AQLQ(S), the AQLQ, the
Medical Outcomes Survey. Short Form 36, the Asthma Control Questionnaire, a
nd spirometry at baseline, 1, 5, and 9 weeks.
Results: Activity domain scores (mean +/- SD) were lower with the AQLQ (5.7
+/- 0.9) than with the AQLQ(S) (5.9 +/- 0.8; p = 0.0003) and correlation b
etween the two was moderate (r = 0.77), However, for overall scores, there
was minimal difference (AQLQ, 5.4 +/- 0.8; AQLQ(S), 5.5 +/- 0.8; r = 0.99),
Reliability (AQLQ intraclass correlation coefficient, 0.99; AQLQ(S) intrac
lass correlation coefficient, 0.96) and responsiveness (AQLQ, p < 0.0001; A
QLQ(S), p < 0.0001) were similar for the two instruments. Construct validit
y (correlation with other measures of health status and clinical asthma) wa
s also similar for the two instruments.
Conclusions: The AQLQ(S) has strong measurement properties and is valid for
measuring health-related quality of Life in asthma, The choice of instrume
nt should depend on the task at hand.