Ten-year healthcare utilization patterns among patients with type 2 diabetes and degenerative spinal disorders: a nationwide comparative analysis using nationwide sample

BACKGROUND: Type 2 diabetes mellitus (T2DM) and degenerative or mechanical spinal disorders frequently co-occur and amplify one another's clinical and socioeconomic burden. T2DM has been associated with greater pain severity, prolonged disability, and higher reported risks of surgery and opioid use, although the underlying mechanisms remain hypothesized rather than established. In South Korea's dual healthcare system, patients may access both Western medicine (WM) and Korean medicine (KM), yet national-level evidence on spine-T2DM multimorbidity care patterns is limited. This study examined 10-year healthcare utilization, expenditures, and medication use among patients with coexisting T2DM and degenerative or mechanical spinal disorders. METHODS: We conducted a retrospective study using the Health Insurance Review and Assessment Service-National Patient Sample (HIRA-NPS) from 2010 to 2019. Patients with both T2DM (E11) and at least one degenerative spinal diagnosis (M47, M48, M51, M54, S33) were included. KM users were defined as those with ≥ 1 KM claim per year. Outcomes included annual claim counts, expenditures, service categories, medication use, and facility type. Annual percent change (APC) was estimated using log-linear regression, and baseline characteristics were compared using standardized mean differences (SMDs). RESULTS: A total of 188,716 patients generated 9,590,400 claims over 10 years; 62.9% were KM users. KM users were more often female and slightly older; back pain (M54) showed the largest imbalance (SMD = 0.26). Total claims increased from 715,279 (2010) to 1,157,475 (2019). KM users had substantially more annual claims; yet per-patient expenditures were similar, reflecting reliance on lower-cost outpatient KM services, notably acupuncture. Medication use peaked in 2012 and declined thereafter following national drug pricing reforms. Non-users received fewer but higher-cost prescriptions, particularly for pain and inflammatory medications. CONCLUSIONS: Adults with coexisting T2DM and degenerative spinal disorders demonstrate increasing and complex healthcare needs driven primarily by chronic pain rather than glycemic management alone. KM users engage in high-frequency, multimodal outpatient care at lower unit cost, whereas non-users rely more heavily on tertiary WM services and higher-cost pharmaceuticals. Korea's dual healthcare system appears to support differentiated care pathways in this multimorbidity population. Findings underscore the need for integrated, longitudinal chronic care models that combine conservative pain management with diabetes care to reduce disability and long-term healthcare burden.