The prevalence of chronic obstructive pulmonary disease in Riyadh, Saudi Arabia: a BOLD study

OBJECTIVE: To estimate the prevalence and associated risk factors of chronic obstructive pulmonary disease (COPD) in Saudi adults aged 40 years using standardised post-bronchodilator spirometry according to the Burden of Obstructive Lung Disease (BOLD) protocol. METHODS: Saudi men and women aged 40 years were recruited by stratified multistage random sampling in Riyadh, Saudi Arabia. Participants completed questionnaires on respiratory symptoms and exposure to risk factors for COPD. Spirometry was performed according to standard methods. COPD was defined as post-bronchodilator FEV1/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio <70% (Global Initiative for Obstructive Lung Disease [GOLD]) or less than the lower limit of normal (LLN) (95th percentile) of the population distribution for FEV1/FVC. RESULTS: Seven hundred subjects underwent acceptable post-bronchodilator spirometry. The overall prevalence of GOLD COPD was 4.2% (men 5.7%, women 2.5%). The overall prevalence of COPD stage 1 or higher using the LLN was lower than estimates using the GOLD criteria (3.2%). The overall prevalence of GOLD stage 2 or higher COPD was 3.7%. Male sex, increasing age and smoking were significantly associated with COPD diagnosis. CONCLUSION: The overall prevalence of COPD in Saudi Arabia is 4.2%. Male, increasing age and smoking were the main risk factors for COPD.