Variation in Resource Utilization for Patients With Hip and Pelvic Fractures Despite Equal Medicare Reimbursement

Medicare currently reimburses hospitals for inpatient admissions with "bundled" payments based on patient Diagnosis-related Groups (DRGs) regardless of true hospital costs. At present, DRG 536 (fractures of the hip and pelvis) includes a broad spectrum of patients with orthopaedic trauma, likely with varying inpatient resource utilization. With the growing incidence of fractures in the elderly, inadequate reimbursements from Medicare for certain patients with DRG 536 may lead to growing financial strain on healthcare institutions caring for these patients with higher costs.

The purposes of the study were to determine whether (1) inpatient length of stay; (2) intensive care unit stay; and (3) ventilator time differ among subpopulations with Medicare DRG 536.

A total of 56,683 patients, 65 years or older, with fractures of the hip or pelvis were identified in the 2011 and 2012 National Trauma Data Bank. This clinical registry contains data on trauma cases from more than 900 participating trauma centers, allowing analysis of resource utilization in centers across the United States. Patients were grouped in the following subgroups: hip fractures (n = 35,119), nonoperative pelvic fractures (n = 15,506), acetabulum fractures, operative and nonoperative, (n = 7670), and operative pelvic fractures (n = 682). Total inpatient length of stay, intensive care unit (ICU) stay, and ventilator time were compared across groups using multivariate analysis that controlled for hospital factors.

After controlling for patient and hospital factors, difference in inpatient length of stay was -0.2 days for patients with nonoperative pelvis fractures compared with inpatient length of stay for patients with hip fractures (95% CI, -0.4 to -0.1 days; p = 0.001); 1.7 days for patient with acetabulum fractures (95% CI, 1.4-1.9 days; p < 0.001); and 7.7 days for patients with operative pelvic fractures (95% CI, 7.0-8.4 days; p < 0.001). The difference in ICU length of stay for patients with nonoperative pelvis fractures was 0.8 days compared with ICU length of stay for patients with hip fractures (95% CI, 0.7-0.9 days; p < 0.001); 1.9 days for patients with acetabulum fractures (95% CI, 1.8-2.1 days; p < 0.001); and 6.3 days for patients with operative pelvic fractures (95% CI, 5.9-6.7 days; p < 0.001). The difference in mechanical ventilation time for patients with nonoperative fractures was 0.5 days compared with ventilation time for patients with hip fractures (95% CI, 0.4-0.6 days; p < 0.001); 1.1 days for patients with acetabulum fractures (95% CI, 1.0-1.2 days; p < 0.001); and 3.9 days for patients with operative fractures (95% CI, 2.5-3.2 days; p < 0.001).

In our current multitiered trauma system, certain centers will see higher proportions of patients with acetabulum and operative pelvic fractures. Because hospitals are reimbursed equally for these subgroups of Medicare DRG 536, centers that care for a greater proportion of patients with more-complex pelvic trauma will experience lower financial margins per trauma patient, limiting their potential for growth and investment compared with competing institutions that may not routinely see patients with high-energy trauma. Because of this, we believe reevaluation of this Medicare Prospective Payment System DRG is warranted.

Level IV, economic and decision analysis.