Healthcare Costs and Trends of Multimorbidity in COPD Patients: A Population-Based Study in Singapore.

Purpose: Chronic obstructive pulmonary disease (COPD) and its comorbidities impose substantial economic burdens on healthcare systems, but evidence remains scarce in Asian countries where patients exhibit distinct clinical and inflammatory phenotypes, as well as policy and health system differences. This study aimed to estimate direct medical costs of COPD multimorbidity, comparing to non-COPD patients in Singapore, and identify high-cost users. Patients and Methods: Using Singapore's health administrative data (2012-2019), we created a propensity score-matched COPD and non-COPD cohort and applied generalised linear models to estimate all-cause, index disease- and comorbidity-attributable costs. All costs were measured in patient-years (PYs) in 2023 Singaporean dollars (SGD$1=US$0.76=₤0.60=€0.69). Patient characteristics and comorbidity prevalence were compared across patients incurring top 10%, 11%-50%, and bottom 50% of average annualised costs. Results: The study included 18,866 patients from each group (83% males, 17% females). Average annual direct medical costs were significantly higher among COPD patients ($5,290.9/PY; 95% confidence interval [CI]: 5,242.9-5,350.1) than non-COPD patients ($1,110.4/PY; 95% CI: 1,085.9-1,135.9). 33.8% of total costs were COPD-attributable, with major contributions from other respiratory (15.0%), circulatory (14.9%), metabolic (7.8%), and digestive (4.7%) diseases. From 2012 to 2019, hospitalisation costs declined (-$59.0/year), while primary care (polyclinic) costs increased sharply (+$148.8/year). Indian patients comprised 67% of the top 10 Conclusion: In Singapore's multi-ethnic Asian context, COPD patients incurred substantial multimorbidity costs, particularly from respiratory, circulatory, and metabolic diseases, underscoring distinct Asian multimorbidity patterns and highlighting the need for integrated, multimorbidity-focused care models. Disproportionately high costs among Indian patients and low female prevalence warrant further investigation.