Development and validation of the EHS-COPD model to predict sex-specific risk of chronic obstructive pulmonary disease (COPD) in older Chinese adults: Hong Kong's Elderly Health Service Cohort.

Background: No screening program is recommended for chronic obstructive pulmonary disease (COPD) in adults based on current clinical practice guidelines. Risk prediction models for COPD developed in Western settings may not be directly applicable to older Chinese adults. To evaluate the performance of an existing risk prediction model for COPD developed in a Western setting in Chinese adults and investigate whether a new risk prediction model performs better in predicting 5-year risk of COPD (EHS-COPD).

Methods: This study is based on 135,822 participants aged 65+ years from Hong Kong's Elderly Health Service (EHS) cohort. We assessed the performance of an existing risk prediction model in the entire cohort, and in a random sub-sample of 91,133 participants, we recalibrated the existing model and derived a new model using extended Cox proportional hazards regression. Candidate risk predictors from the literature and the EHS cohort were considered for inclusion. Risk prediction performance, discrimination, and calibration of the newly derived models were assessed in the remaining 44,689 participants.

Results: The existing risk prediction model overestimated the 5-year risk of COPD in older Chinese adults (65+ years); after recalibration, it still overestimated the 5-year risk of COPD for both men and women. The new EHS-COPD risk prediction model, including time-varying factors (i.e., age and smoking status) and time-invariant factors (i.e., education level, public assistance, alcohol use, body mass index, physical activity, existing hypertension, recent falls, cognitive function, and self-rated health status), had an improved performance. For men, EHS-COPD explained 19.5% of COPD risk, the D statistic was 23.1, and Harrell's C statistic was 0.93. The corresponding values for women were 8.5%, 21.1, and 0.93.

Conclusions: The existing COPD risk prediction model overpredicted COPD risk in older Chinese and could not be recalibrated to predict well. A revised prediction model using time-invariant and time-varying factors provides a better tool for identifying older Chinese adults at high risk of developing COPD.