Am. J. Respir. Crit. Care Med.,
Volume 158, Number 4, October 1998, 1082-1090
Is the Asthma Quality of Life Questionnaire a Useful
Measure for Low-income Asthmatics?
NANCY KLINE
LEIDY,
KITTY S.
CHAN,
and
CECELIA
COUGHLIN
Center for Health Outcomes Research, MEDTAP International Inc., Bethesda, Maryland; and Center for Health Care
Policy and Evaluation, United Healthcare, Minneapolis, Minnesota
The purpose of this study was to evaluate the reliability and validity of the Asthma Quality of Life
Questionnaire (AQLQ) in a population-based sample of low-income adults with asthma. A total of
112 subjects (46 African American, 66 Caucasian; mean age = 33 ± 9 yr; 26% male) were recruited
from the Baltimore County, Maryland and Atlanta, Georgia metropolitan areas. Internal consistency reliability (Cronbach's
) was high for the overall scale (0.96); 2-wk reproducibility (intraclass correlation, ICC) was 0.82 (n = 38). Overall score was significantly correlated with FEV1 percentage of predicted (r = 0.20), and the Asthma Disease Severity Scale (r =
0.38). Correlations between overall
score and the SF-36 Physical Component Summary (r = 0.49), SF-36 Mental Component Summary
(r = 0.37), Cantril's Ladder (r = 0.23), and the Health Utilities Index (r = 0.22) supported the validity
of the AQLQ in this sample. Comparison of reliability and validity estimates across racial groups
found few substantive differences. Internal consistency, reproducibility, and validity estimates found
in this sample were consistent with those of a reliable and valid measure and were comparable to
those found in other populations. These results suggest the AQLQ is a useful indicator of health- related quality of life in low-income asthmatics.