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

Yah Ru Juang,1,* Laura Huey Mien Lim,1,* Sanjay H Chotirmall,2,3 John Abisheganaden,2– 4 Mariko Siyue Koh,5 Ming-Ju Tsai,6,7 Mei Fong Liew,8– 10 Anthony Chau Ang Yii,11 Pei Yee Tiew,2,5 David Price,12– 14 Kelvin Bryan Tan,1,15 Wenjia Chen1 1Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore; 2Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore; 3Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore, Singapore; 4Health Services and Outcomes Research, National Healthcare Group, Singapore, Singapore; 5Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore, Singapore; 6Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; 7Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 8Division of Respiratory and Critical Care Medicine, Department of Medicine, National University Hospital, National University Health System, Singapore, Singapore; 9Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; 10Division of Respiratory and Critical Care Medicine, Integrated Medicine Programme, Alexandra Hospital, Singapore, Singapore; 11Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore, Singapore; 12Observational and Pragmatic Research Institute, Singapore, Singapore; 13Optimum Patient Care, Cambridge, UK; 14Centre of Academic Primary Care, Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK; 15Ministry of Health, Singapore, Singapore*These authors contributed equally to this workCorrespondence: Wenjia Chen, Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore, Tel +6596637487, Email [email protected]: 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 10th cost percentile and experienced frequent hospitalisations (≥ 2/year).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.Keywords: COPD, multimorbidity, comorbidities, economic burden, direct costs, health administrative data