Chronic obstructive pulmonary disease in the adult population within the Middle East and North Africa region: rationale and design of the BREATHE study

The objective of the BREATHE study was to estimate the regional prevalence of chronic obstructive pulmonary disease (COPD) symptoms within the general population in the Middle East/North Africa (MENA) region and to document risk factors, disease characteristics and management using a standardised methodology. This was an observational population-based survey performed in ten countries in the Middle East and North Africa (Algeria, Egypt, Jordan, Lebanon, Morocco, Saudi Arabia, Syria, Tunisia, Turkey and United Arab Emirates), together with Pakistan. A general population sample of 10,000 subjects >= 40 years of age in each country or zone was generated from random telephone numbers. Structured interviews were proposed by telephone. A screening questionnaire was administered to each subject collecting information on respiratory symptoms and smoking habits. Subjects with chronic bronchitis or breathlessness and smoking >= 10 pack years fulfilled the epidemiological definition of COPD ("COPD" population). This population then completed a full disease questionnaire, the COPD Assessment Test (CAT) and a cost-of-disease questionnaire. A randomly selected sample was also assessed by spirometry. In all, 457,258 telephone numbers were generated and contact was established with 210,121 subjects, of whom 65,154 were eligible and 62,086 accepted to participate. The overall response rate was 74.2%. 2,187 (3.5%) subjects fulfilled the criteria for the "COPD" population. Evaluable spirometry data were obtained from 1,847 (14.2%) subjects to whom it was proposed.