Global, regional, and national prevalence of, and risk factors for, chronic obstructive pulmonary disease (COPD) in 2019: a systematic review and modelling analysis

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is an increasingly important cause of morbidity, disability, and mortality worldwide. We aimed to estimate global, regional, and national COPD prevalence and risk factors to guide policy and population interventions. METHODS: For this systematic review and modelling study, we searched MEDLINE, Embase, Global Health, and CINAHL, for population-based studies on COPD prevalence published between Jan 1, 1990, and Dec 31, 2019. We included data reported using the two main case definitions: the Global Initiative for Chronic Obstructive Lung Disease fixed ratio (GOLD; FEV(1)/FVC<0·7) and the lower limit of normal (LLN; FEV(1)/FVC<LLN). We employed a multilevel multivariable mixed-effects meta-regression approach to generate the age-specific and sex-specific prevalence of COPD in 2019 for high-income countries (HICs) and low-income and middle-income countries (LMICs) according to the World Bank definition. Common risk factors for GOLD-COPD were evaluated using a random-effects meta-analysis. FINDINGS: We identified 162 articles reporting population-based studies conducted across 260 sites in 65 countries. In 2019, the global prevalence of COPD among people aged 30–79 years was 10·3% (95% CI 8·2–12·8) using the GOLD case definition, which translates to 391·9 million people (95% CI 312·6–487·9), and 7·6% (5·8–10·1) using the LLN definition, which translates to 292·0 million people (219·8–385·6). Using the GOLD definition, we estimated that 391·9 million (95% CI 312·6–487·9) people aged 30–79 years had COPD worldwide in 2019, with most (315·5 million [246·7–399·6]; 80·5%) living in LMICs. The overall prevalence of GOLD-COPD among people aged 30–79 years was the highest in the Western Pacific region (11·7% [95% CI 9·3–14·6]) and lowest in the region of the Americas (6·8% [95% CI 5·6–8·2]). Globally, male sex (OR 2·1 [95% CI 1·8–2·3]), smoking (current smoker 3·2 [2·5–4·0]; ever smoker 2·3 [2·0–2·5]), body-mass index of less than 18·5 kg/m(2) (2·2 [1·7–2·7]), biomass exposure (1·4 [1·2–1·7]), and occupational exposure to dust or smoke (1·4 [1·3–1·6]) were all substantial risk factors for COPD. INTERPRETATION: With more than three-quarters of global COPD cases in LMICs, tackling this chronic condition is a major and increasing challenge for health systems in these settings. In the absence of targeted population-wide efforts and health system reforms in these settings, many of which are under-resourced, achieving a substantial reduction in the burden of COPD globally might remain a difficult task. FUNDING: National Institute for Health Research and Health Data Research UK.