Impact of Undiagnosed COPD and Asthma on Symptoms, Quality of Life, Healthcare Utilization and Work Productivity.

A significant proportion of individuals with COPD and asthma remain undiagnosed. The objective of this study was to evaluate symptoms, quality of life, healthcare utilization and work productivity in subjects with undiagnosed COPD or asthma compared to those previously diagnosed, as well as healthy controls. This multi-center population-based case-finding study randomly recruited adults with respiratory symptoms who had no previous history of diagnosed lung disease from 17 Canadian centers using random digit-dialing. Participants who exceeded symptom thresholds on The Asthma Screening Questionnaire or the COPD Diagnostic Questionnaire underwent pre- and post-bronchodilator spirometry to determine if they met diagnostic criteria for COPD or asthma. Two control groups, a healthy group without respiratory symptoms and a symptomatic group with previously diagnosed COPD or asthma, were similarly recruited. 26,905 symptomatic individuals were interviewed, and 4,272 subjects were eligible. Of these, 2,857 completed pre and post bronchodilator spirometry and 595 (21%) met diagnostic criteria for COPD or asthma. Individuals with undiagnosed COPD or asthma reported greater impact of symptoms on health status and daily activities, worse disease-specific and general quality of life, greater healthcare utilization and poorer work productivity compared to healthy controls. Individuals with undiagnosed asthma had similar symptoms, quality of life, and healthcare utilization burden compared to those with previously diagnosed asthma, while subjects with undiagnosed COPD were less disabled compared to those with previously diagnosed COPD. Undiagnosed COPD or asthma impose important, unmeasured burdens on the healthcare system and are associated with poor health status and negative effects on work productivity.