Do deaths from competing risks influence COPD patterns in China and high socio-demographic index countries?: a cross-sectional analysis of summary statistics from the Global Burden of Disease Study 2017

OBJECTIVE: To explore possible reasons for the difference in chronic obstructive pulmonary disease (COPD) incidence/mortality rates between China and high socio-demographic index (SDI) countries. DESIGN: A cross-sectional analysis of summary statistics from the Global Burden of Disease Study 2017. PARTICIPANTS: Data were publicly available and de-identified, and individuals were not involved. MEASUREMENT AND METHODS: We extracted the age-standardised and age-specific incidence/mortality rates, and risk factors attributed to COPD in China and high SDI countries from the Global Burden of Disease Study 2017. We first described differences in COPD patterns (ie, incidence and mortality rates) in China and high SDI countries briefly, and then explored possible reasons for driving such differences by comparing rankings for six well-established COPD risk factors and estimating change points in age-specific incidence and mortality rates for COPD and several commonly encountered competing risks using segmented regression models. RESULTS: Differences in age-standardised incidence and mortality rates for COPD between China and high SDI countries converged during 1990–2017 but still differed, particularly for mortality rates. Smoking was the leading attributable risk factor followed by ambient air pollution, with higher rankings for occupational risks in China than in high SDI countries. The change point was ~80 years for age-specific COPD mortality rate in both China and high SDI countries. However, the change point for COPD incidence was 5-year later in China (~65 years) than in high SDI countries (~60 years). The change points for mortality rates due to competing risks (eg, ischaemic heart disease) also varied between settings. CONCLUSION: Differences in risk factors largely shaped the differences in COPD patterns between China and high SDI countries. Varying patterns of mortality due to competing risks might also contribute to the discrepancy in COPD mortality rates, by affecting the survival of the underlying population.