Associations of multimorbidity burden with healthcare utilization and expenditures among individuals with diabetes in China

Objective Multimorbidity is common among people with diabetes, but its associations with healthcare utilization and medical expenditures in China remain insufficiently characterized. This study aimed to examine these associations using different measures of multimorbidity burden and assess potential sex differences. Methods We conducted cross-sectional analyses using the 2018 China Health and Retirement Longitudinal Study (CHARLS) and a retrospective hospital-based cohort. Multimorbidity burden was assessed using four measures: multimorbidity, ≥3 LTCs, number of long-term conditions (LTCs), and the Chinese Multimorbidity-Weighted Index (CMWI). Multivariable regression models were used to examine associations with healthcare utilization and expenditures. Sex-stratified analyses, interaction tests, and sensitivity analyses were also performed. Results Among 2,531 CHARLS participants with diabetes, 92.9% had multimorbidity and 77.7% had ≥3 LTCs. All four measures were positively associated with inpatient and outpatient utilization, visit counts, and medical expenditures. The presence of ≥3 LTCs was associated with higher odds of inpatient (OR, 2.44; 95% CI, 1.90–3.16) and outpatient utilization (OR, 2.17; 95% CI, 1.68–2.84), as well as higher total inpatient (cost ratio, 2.98; 95% CI, 1.94–5.24) and outpatient expenditures (cost ratio, 3.15; 95% CI, 1.92–5.72). In the hospital cohort ( n = 3,963), all four measures were positively associated with hospitalization frequency, cumulative inpatient days, and inpatient expenditure. Most sex interaction tests were not statistically significant. Sensitivity analyses yielded generally consistent findings. Conclusion Greater multimorbidity burden was associated with higher healthcare utilization and medical expenditures among individuals with diabetes across two different settings. These findings highlight the importance of considering coexisting conditions in healthcare planning.