Validity of a modified version of the Marks Asthma Quality of Life Questionnaire

To produce a scale useful for individual clinical decision making, the Mark s Asthma Quality of Life Questionnaire (AQLQ-M) was modified to a 22-item s cale using a 7-point Likert response scale, and the validity of the new ins trument was assessed. Adult asthma subjects with moderate to severe disease , recruited from two hospitals in Adelaide, Australia, were surveyed at bas eline (n = 293), and at 3-month follow-up (n = 234). Cronbach's alpha for t he Total scale of the modified AQLQ-M (MAQLQ-M) was 0.97 and all subscale v alues exceeded 0.90. Test-retest reliability values for all scales were bet ween 0.88 and 0.93. All correlations between disease reference measures wer e statistically significant to at least the p < 0.01 level. Stronger associ ations were seen with symptom and self-rating scales than for lung function , medication usage, and health service utilization measures of outcome. The MAQLQ-M showed good discriminative ability for all asthma symptom categori es and for different FEV,values. Moderate, statistically significant associ ations were seen between changes in MAQLQ-M scores and clinical measures. H igher baseline MAQLQ-M scores were associated with lower risks over 12 mont hs for hospital admissions (odds ratio, OR = 0.58) and repeated emergency d epartment visits (OR = 0.47). The MAQLQ-M is a highly valid measure of asth ma-related quality of life.