Changes in healthcare delivery following spinal fracture in Medicare Accountable Care Organizations.

Background Context: Accountable Care Organizations (ACOs) were designed to reduce healthcare costs while simultaneously improving quality. Given that the success of ACOs is predicated on controlling costs, concerns have been expressed that patients could be adversely affected through restricted access to surgery, including in the context of spine fracture care.

Purpose: Evaluate the impact of Medicare ACO formation on the utilization of surgery and outcomes following spinal fractures.

Study Design: Retrospective review of Medicare claims (2009-2014).

Patient Sample: Patients treated for spinal fractures in an ACO or non-ACO.

Outcome Measures: The utilization of surgery as treatment for spinal fractures, in-hospital mortality, 90-day complications, or hospital readmission within 90-days injury.

Methods: We used a pre-post study design to compare outcomes for patients treated in ACOs versus non-ACOs. Receipt of surgery for treatment of a spinal fracture was the primary outcome, with mortality, complications and readmissions treated secondarily. We used multivariable logistic regression adjusting for confounders to determine the association between environment of care (ACO vs. non-ACO) and the outcomes of interest. In all testing, beneficiaries treated in non-ACOs during 2009 to 2011 were used as the referent.

Results: During 2009 to 2011, 9% (n=10,866) of patients treated in non-ACOs received surgery, whereas a similar percentage (9%; n=210) underwent surgery in ACOs. This figure decreased to 8% (n=9,857) for individuals treated in non-ACOs over 2012 to 2014, although the surgical rate remained unchanged for those receiving care in an ACO (9%; n=227). There was no difference in the use of surgery among patients treated in ACOs (OR 0.96; 95% CI 0.79, 1.18) over 2012 to 2014. Similar increases in the odds of mortality were observed for both ACOs and non-ACOs during this period. A marginal, yet significant increase in complications was observed among ACOs, although there was no change in the odds of readmission.

Conclusions: Our study found that the formation of ACOs did not result in alterations in the use of surgery for spinal fractures or substantive changes in outcomes. As ACOs continue to evolve, more emphasis should be placed on the incorporation of measures directly related to surgical and trauma care in the determinants of risk-based reimbursements.