Case finding for chronic obstructive pulmonary disease: a model for optimising a targeted approach

Objectives Case finding is proposed as an important component of the forthcoming English National Clinical Strategy for chronic obstructive pulmonary disease (COPD) because of accepted widespread underdiagnosis worldwide. However the best method of identification is not known. The extent of undiagnosed clinically significant COPD in England is described and the effectiveness of an active compared with an opportunistic approach to case finding is evaluated. Methods A cross-sectional analysis was carried out using using Health Survey for England (HSE) 1995-1996 data supplemented with published literature. A model comparing an active approach (mailed questionnaires plus opportunistic identification) with an opportunistic-only approach of case finding among ever smokers aged 40-79 years was evaluated. There were 20 496 participants aged >= 30 years with valid lung function measurements. The main outcome measure was undiagnosed clinically significant COPD (any respiratory symptom with both forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC