The Marks Asthma Quality of Life Questionnaire: Further validation and examination of responsiveness to change

We performed analyses to examine the structure, validity, and responsivenes s to change of the Marks Asthma Quality of Life Questionnaire (AQLQ), origi nally validated in Australia in a self-administered format, among 539 U.S. subjects with asthma. Subjects were interviewed twice by telephone over an 18-month period. Based on factor analyses, the subscale structure of the AQ LQ was modified slightly to eliminate item overlap among subscale scores. C ross-sectionally, total AQLQ scores were significantly correlated in expect ed directions with baseline asthma severity scores (r = 0.58), SF-36 physic al (r = -0.66) and mental (r = -0.40) health status scores, and pulmonary f unction (FEV1% predicted, r = -0.14). Longitudinally, changes in AQLQ total and subscale scores were significantly (P < 0.01) associated with changes in asthma severity and both physical and mental status. The AQLQ, administe red by telephone, appears to be useful for assessing changes in the impact of adult asthma. (C) 1999 Elsevier Science Inc.