Inequalities in disease burden and care quality of chronic obstructive pulmonary disease, 1990-2021: Findings from the Global Burden of Disease Study 2021.

Background: Chronic obstructive pulmonary disease (COPD) is one of the primary causes of significant morbidity and mortality worldwide. This study aimed to explore the cross-country inequalities by age, sex, and region in COPD's burden and care quality from 1990 to 2021. Methods: We obtained data from the Global Burden of Disease 2021. Using age-standardised disability-adjusted life years rate (ASDR) per 100 000 population and quality of care index (QCI), we quantified the COPD burden and care quality, respectively. Applying the principal component analysis method, we calculated QCI scores, ranging from 0 to 100, where higher values indicate better care quality. We quantified temporal trends from 1990 to 2021 for ASDR and QCI by estimated annual percentage change (EAPC). Finally, we assessed the absolute and relative disparities in ASDR and QCI across countries using the slope index of inequality (SII) and concentration index. Results: Between 1990 and 2021, there was a notable decline in ASDR of COPD globally (1990 = 1492.64; 2021 = 940.66; EAPC = -1.71), accompanied by an increase in QCI (1990 = 58.42; 2021 = 73.86; EAPC = 0.89). Regions with middle sociodemographic index (SDI) consistently demonstrated the highest ASDR and the lowest QCI in 1990 (ASDR = 2332.91; QCI = 31.70), whereas by 2021, low-middle SDI regions exhibited similar trends (ASDR = 1707.90; QCI = 57.50). In 2021, the highest ASDR was among individuals aged 95 years and above (16251.22), while the lowest QCI was among people aged 70-74 years (72.18). Papua New Guinea recorded the highest ASDR and the lowest QCI in 2021 (ASDR = 3004.36; QCI = 19.18). Compared to 1990, where the SII for ASDR was -612.44 and for QCI was 21.78, with concentration indices of -0.14 for ASDR and 0.11 for QCI, the absolute values of both SII and concentration index were smaller in 2021, with ASDR's SII at -555.90, QCI's at 16.72, ASDR's concentration index at -0.13, and QCI's at 0.04. Conclusions: The global burden of COPD decreases and care quality increases over time, with notable variations across ages, sexes and SDI regions. Countries with lower SDI had disproportionately higher burden and poorer care quality for COPD.