The structure of symptom report in asthma: a reevaluation.

Objectives: We studied the structure of symptom report in a sample of British asthma patients using the Asthma Symptom Checklist (ASC).

Methods: The ASC was administered to 193 patients, together with a questionnaire on demographics and asthma-related information and the Perceived Control of Asthma Questionnaire.

Results: Principal Component Analysis yielded evidence for a six-dimensional structure of the ASC, with positively correlated subscales for panic-fear, irritation, obstruction-dyspnea, obstruction-congestion, fatigue, and hyperventilation symptoms. Individual subscales showed good to excellent item characteristics and internal consistencies in individual subscales. Panic-fear and obstruction-congestion were related to self-reported duration of oral corticosteroid intake. Other ASC subscales were positively related to aspects of health care utilization, limitations in daily activity, and lower perceived control of asthma mainly in women. The dyspnea subscale of the ASC showed only little relationship with either of these variables.

Conclusion: The ASC can reliably assess the multidimensional structure of asthma symptom report. Its subscales are associated with important aspects of asthma management behavior.