Burden of obstructive lung disease study in Tehran: Prevalence and risk factors of COPD

Background: Chronic Obstructive Pulmonary Disease (COPD) was ranked as the sixth most common cause of death worldly wide in 1990, but has been planned to become the third-most common cause by the year 2030. The goal of the present project is to describe the prevalence and determining the causes and risk factors of COPD in the population of Tehran. Materials and Methods: This study follows a stratified cluster sampling strategy with proportional allocation within strata. The target population is all non-institutionalized inhabitants, aged 18 to 40 in one group and over 40 in another, who inhabit in Tehran city in the year 2013. The single most important outcome measure obtained as part of this protocol is spirometry before and after administration of 200 mg (2 puffs) of salbutamol. Results: The most reported respiratory symptoms were: 291 (16.2%) sputum production (95% CI: 14.5-17.9%), 171 (9.5%) chronic cough (95% CI: 8.2-10.9 %), and 377 (21.0%) wheezing (95%CI: 19.1-22.9%). As for dyspnea, 388 (21.6%) (95% CI: 19.7-23.5%) of participants had this sign during last year. The overall COPD prevalence defined by the Postbronchodilator spirometric functional criteria was 9.2%, higher in men (10.1%) than in women (8.5%); the prevalence was significantly higher in subjects aged over 55 years (p ≤ 0.002). Conclusion: The high prevalence of verifiied COPD, a great deal of which was undiagnosed before by a physician, provokes the necessity of raising awareness of this disease among health professionals, and needs more use of spirometry in the primary care setting.