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Global prevalence of chronic obstructive pulmonary disease: systematic review and meta-analysis.

Background
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide.


Aims
To synthesize data on the worldwide prevalence and severity of COPD by geographical region, age groups, and smoking status in a systematic review.


Methods
A systematic search was performed following Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. International databases including PubMed, Scopus and Web of Science were searched for population- based studies published between January 2004 and May 2015 that reported the prevalence of COPD anywhere in the world. The prevalence of COPD was calculated based on World Health Organization (WHO) regions and sex and severity stages using metaprop. Meta-regression and subgroup analysis were applied to determine the sources of heterogeneity.


Results
Sixty papers were screened with a combined subject sample size of 127 598. The prevalence of post-bronchodilator COPD was 12.16% (10.91-13.40%). The pooled prevalence of COPD was 15.70% (13.80-18.59%) in men and 9.93% (8.73- 11.13%) in women. Among all WHO regions, the highest prevalence was recorded in the Region of the Americas (14.53%), and the lowest was recorded in the South-East Asia Region/Western Pacific Region (8.80%). Meta-regression model variables were: sample size, WHO region, study quality score, level of gathering data, publication year, and sampling methods that justified 29.82% of heterogeneity detected among COPD prevalence rates worldwide.


Conclusions
Global prevalence of COPD among men is about 5% higher than among women. The most prevalent stage of COPD is stage 1.