QUALITY-OF-LIFE IN ASTHMA .1. INTERNAL CONSISTENCY AND VALIDITY OF THE SF-36 QUESTIONNAIRE

Asthma is a chronic disease in which social life is altered. The impor tance of restrictions on social life may be greater in severe asthma o r when symptoms are not adequately controlled. General scales of quali ty-of-life (QOL) may be used to detect the importance of social life i mpairment, but it is not yet known whether the scores of such QOL meas ures are reliable and valid in asthmatic patients. A study was carried out in 252 patients with asthma of variable severity (FEV(1) ranging from 25 to 131% of predicted) to assess the validity of a general QOL scale, the first French version of the SF-36 health status questionnai re (SF-36). This is based on 36 items selected to represent nine healt h concepts (physical, social, and role functioning; mental health; hea lth perceptions; energy or fatigue; pain; and general health). All nin e SF-36 category scores were highly significantly correlated with the severity of asthma assessed by the clinical score of Aas (p < 0.0007 t o p < 0.0001). Eight SF-36 category scores were highly significantly c orrelated with FEV, (p < 0.003 to p < 0.0001). A high internal reliabi lity of SF-36 was found using the alpha coefficient of Cronbach (0.91 for the whole questionnaire). The SF-36 questionnaire is valid and rel iable in asthma and can therefore be used to examine QOL in asthmatic and nonasthmatic patients and to determine to what extent asthma impai rs social life.