Background: In the original 32-item Asthma Quality of
Life Questionnaire (AQLQ), 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 formulated five generic activities (strenuous exercise,
moderate exercise, work-related activities, social activities, and
sleep) to replace the five patient-specific activities in the AQLQ. In
a 9-week observational study, we compared the AQLQ with the AQLQ(S) and
examined their measurement properties. Forty symptomatic adult asthma
patients completed the AQLQ(S), the AQLQ, the Medical Outcomes Survey
Short Form 36, the Asthma Control Questionnaire, and 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
between 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, 0.95; AQLQ(S) intraclass correlation coefficient, 0.96)
and responsiveness (AQLQ, p < 0.0001; AQLQ(S), p < 0.0001) were
similar for the two instruments. Construct validity (correlation with
other measures of health status and clinical asthma) was 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 instrument should depend on
the task at hand.
ACQ = asthma control questionnaire; AQLQ = Asthma Quality of Life
Questionnaire; AQLQ(S) = standardized version of the AQLQ;
ICC = intraclass correlation coefficient; PEF = peak expiratory
flow; SF-36 = Medical Outcomes Survey Short Form 36