Medicare's Benchmarking Spinal DRGs have Limited Capacity in Capturing the Nuances of Surgical Invasiveness, Hospital Length of Stay, Discharge Disposition, Key Quality Metrics, and Reimbursement Costs for Adult Spinal Deformity.

Abstract

Study designRetrospective cohort analysis.ObjectiveAssess the distribution of Medicare's spinal-deformity-specific diagnosis-related group (DRGs) relative to surgical invasiveness, hospital length of stay (LOS), discharge disposition, 90-day post-operative quality metrics, and reimbursement costs for adult spinal deformity (ASD) operations.Summary of background dataHeterogeneity of ASD call into question Medicare's DRGs to accurately capture nuances of ASD surgical episodes of care.MethodsAdults who underwent thoracic to pelvis instrumentation with associated DRGs were identified from a multi-center database. Demographics, operative details, inpatient course, discharge disposition, 90-day adverse events, and reimbursement costs were compared between spinal deformity-specific DRG codes. Distribution of DRGs for a subset of these patients who fit into one of 6 commonly performed surgical strategies to address ASD were also assessed.ResultsOf the 314 patients included for analysis, the majority fell into +CC DRGs, while the minority had +MCC DRGs or no MCC/CC DRG. Within each DRG there was considerable heterogeneity in regard to patients' ages, ASA, CCI, frailty, surgical invasiveness, post-operative ICU/hospital LOS, discharge disposition, and complication profiles.+MCC DRGs had significantly greater ASA and Edmonton Frailty Scores. While +MCC and +CC had relatively similar surgical invasiveness, +MCC had greater ICU admissions, in-hospital adverse events, and non-home discharges as well as longer ICU, hospital, and rehab LOS. While reimbursements were significantly higher for +MCC DRG compared to +CC DRGs and DRGs without MCC/CC, there were large ranges in reimbursement within all DRG subgroups.The 7 DRGs varied significantly within and between the subset of 6 commonly performed surgical strategies, although there were no differences in regard to ICU admissions and LOS, hospital LOS, discharge disposition, and number of adverse events (in-hospital, 90-day).ConclusionsWhile Medicare's spinal-deformity DRG codes capture average trends in surgical/post-operative episodes of care for ASD patients, each encompasses highly heterogeneous patients and associated surgical operations rendering them unreliable gauges of patient/surgical complexity, early post-operative trajectories, and reimbursement costs. A more granular system is needed to more accurately capture the nuances of ASD operations and their associated quality metrics and reimbursement costs.