Medicare's benchmarking spinal DRGs have limited utility in capturing key quality metrics for adult spinal deformity (ASD)

BACKGROUND CONTEXT: Heterogeneity of adult spinal deformity (ASD) and associated surgical options call into question Medicare's spinal-deformity-specific diagnosis-related group (DRG) to accurately capture nuances of episodes of care associated with ASD operations. PURPOSE: To assess utility of Medicare's DRGs in capturing surgical complexity, hospital length of stay (LOS), discharge disposition, and key quality metrics within 90-days following ASD operations. STUDY DESIGN/SETTING: Retrospective cohort analysis of prospectively collected data. PATIENT SAMPLE: ASD patient operations including instrumentation from the thoracic spine (UT:T1-6; LT: T6-T12) to the pelvis. OUTCOME MEASURES: Patient demographics, operative details, postoperative inpatient course, discharge disposition, and 90-day adverse events. METHODS: A prospective, multi-center database of ASD operations were retrospectively queried. Included patients had instrumentation from the thoracic spine (UT:T1-6; LT: T6-T12) to the pelvis and associated DRGs and reimbursement costs. Patient demographics, operative details, postoperative inpatient course, discharge disposition, and 90-day adverse events were compared between the assigned spinal deformity-specific DRG codes (453,454,455,456,457,458,460). Also assessed was distribution of DRGs for a subset of these patients who fit into one of 6 commonly performed surgical strategies to address ASD: (1) primary LT-pelvis + TLIFs; (2) primary LT-pelvis + ALIFs; (3) primary UT-pelvis + TLIFs; (4) primary UT-pelvis + ALIFs; revision LT-pelvis +/- interbodies; (6) revision thoracic (T1-T12)-pelvis + 3CO +/- interbodies. Statistical analyses consisted of ANOVA for continuous variables and Fisher Exact tests for categorical variables. RESULTS: Of 489 total patients, 314 met inclusion criteria with complete DRG and reimbursement cost data. The majority of patients fell into +CC DRG groups (454 - 48.7%; 457 - 20.1%), while the minority had +MCC DRGs (453 - 12.7%; 456 - 5.7%) or no MCC/CC DRG (455 - 5.1%; 458 - 3.2%; 460 - 4.8%). Within each DRG there was considerable heterogeneity in regard to patients’ ages, ASA, CCI, frailty, surgical complexity, postoperative ICU and hospital lengths of stay, discharge disposition, and complication profiles. +MCC DRGs (453/456) had significantly greater CCI and Edmonton frailty scores. +MCC (453/456) and +CC (453/456) had relatively similar type of operation (primary v. revision), thoracic UIV level, and 3-CO. Despite this, +MCC were admitted to the ICU more frequently, had longer ICU LOS, had greater number of in-hospital adverse events, longer overall hospital LOS, were more commonly discharged to rehab/SNF, and had longer rehabilitation LOS. Reimbursements were highest for +MCC DRGs. DRGs with no MCC/CC (455/458) had greater percentages of primary operations, LT UIVs, and fewer 3-CO, less frequently received a blood transfusion, had fewer ICU admissions, shorter hospital LOS, greater percentage of discharges to home, and fewer in-hospital and 90-day adverse events compared to +MCC/+CC DRGs. Reimbursements were lowest for DRGs without MCC/CC. For the subset of 6 commonly performed surgical strategies (n=196), the 7 DRGs varied significantly within and between the groups, although there were no differences in regard to ICU admissions, ICU LOS, overall hospital LOS, discharge disposition, and number of in-hospital and 90-day adverse events. CONCLUSIONS: While Medicare's spinal-deformity DRG codes capture average trends in surgical and postoperative episodes of care for ASD patients, each encompasses highly heterogeneous patients and associated surgical operations rendering them unreliable gauges of patient and surgical complexity and early postoperative trajectories. As such, a more granular grading system is needed to more accurately capture the nuances of ASD operations and their associated quality metrics. FDA Device/Drug Status: This abstract does not discuss or include any applicable devices or drugs.

Duke Scholars

Author Christopher Ignatius Shaffrey Orthopaedic Surgery

Author Peter Passias Orthopaedic Surgery