Prevalence and Risk Factors of Chronic Obstructive Pulmonary Disease in Kazakhstan in a Nationwide Population-Based...

Until recently, reports on chronic obstructive pulmonary disease (COPD) in Kazakhstan have been sporadic and reflected the disease burden in only one largest city, Almaty. We, therefore, aimed to characterize the prevalence and risk factors of COPD confirmed with a high-quality spirometry in a nationwide population-based study.

We enrolled 5058 subjects, and hereinafter analyzed complete data for 4626 (age 47; interquartile range (IQR) 31;60 years) participants from the general population from five cities in Kazakhstan representing the West, North, South, East and the central part to fill in a questionnaire and undergo spirometry with bronchodilation. COPD was confirmed when post-bronchodilation forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC) was below -1.64 z-scores. The association of selected predictors with COPD was tested in multivariate regression models.

Seven percent of the entire group (9% in men vs 6% in women) had COPD. The corresponding prevalence in the group 40 years and older was 10.7% (14.5% in men and 7.6% in women). For ΔFVC, 78% could achieve A or B quality, whereas 83% could attain A or B quality for ΔFEV₁. Only 30% of COPD patients were told they had it before. Ever-smoking (OR 2.44; 95% CI 1.81;3.33), low educational level (OR 1.80; 95% CI 1.42;2.28), exposure to vapors, gases, dusts and fumes (VGDF) (OR 1.41; 95% CI 1.10;1.82) and tuberculosis in the past (OR 4.12. 95% CI 2.19;7.45), adjusted for each other, age, sex and physical activity put subjects at risk for COPD.

COPD in Kazakhstan remains a highly underdiagnosed disease. Most COPD patients do not yet have a timely diagnosis and remain untreated. Smoking, occupational exposures and even tuberculosis in the past significantly increase the risk of this disease.