Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P68. Alterations in 90-day morbidity, mortality and readmission rates following spine surgery in Medicare accountable care organizations (2009–2014)

Abstract

BACKGROUND CONTEXT The impact of accountable care organizations (ACOs) on health care quality and outcomes, including morbidity, mortality and readmissions, has not been substantially investigated, especially following spine surgery. PURPOSE To evaluate the impact of ACO formation on postoperative outcomes in the 90-day period following spine surgery STUDY DESIGN/SETTING Retrospective review of a 100% sample of Medicare claims (2009–2014). PATIENT SAMPLE Patients who underwent one of four lumbar spine surgical procedures in an ACO or nonACO. OUTCOME MEASURES The development of in-hospital mortality, complications or hospital readmission within 90-days of the surgical procedure. METHODS The primary outcome measures included post-surgical complications and readmissions at 90-days following surgery. In-hospital mortality and 30-day outcomes considered secondarily. The primary predictor variable consisted of ACO enrollment designation. Multivariable logistic regression analysis was utilized to adjust for confounders and determine the independent effect of ACO-enrollment on postsurgical outcomes. The multivariable model included a propensity score adjustment that accounted for factors associated with the preferential enrollment of patients in ACOs; namely socio-demographic characteristics, medical co-morbidities, hospital teaching status, bed size and location. RESULTS In all, there were 344,813 patients identified for inclusion in this analysis with 97% (n=332,890) treated in nonACOs and 3% (n=11,923) in an ACO. Although modest changes were apparent across both ACOs and nonACOs over the time-period studied, improvements were slightly more dramatic in nonACOs leading to statistically significant differences in both 90-day complications and readmissions. Specifically, in the period 2012-2014, ACOs demonstrated an 18% increase in the likelihood of 90-day complications and a 14% elevation in the likelihood of 90-day readmissions when compared to nonACOs. There was no difference in hospital mortality between ACOs and nonACOs. CONCLUSIONS Our study of Medicare data from 2009 to 2014 failed to demonstrate superior reductions in postoperative morbidity, mortality and readmissions for beneficiaries treated in ACOs as compared to nonACOs. These results indicate that meaningful changes in postoperative outcomes should not be anticipated based on organizational participation in ACOs at present.