Anticipating the effects of accountable care organizations for inpatient surgery

Much of the enthusiasm for accountable care organizations is fueled by evidence that integrated delivery systems (IDSs) perform better on measures of quality and cost in the ambulatory care setting; however, the benefits of this model are less clear for complex hospital-based care.

To assess whether existing IDSs are associated with improved quality and lower costs for episodes of inpatient surgery.

We used national Medicare data (January 1, 2005, through November 30, 2007) to compare the quality and cost of inpatient surgery among patients undergoing coronary artery bypass grafting, hip replacement, back surgery, or colectomy in IDS-affiliated hospitals compared with those treated in a matched group of non-IDS-affiliated centers.

Operative mortality, postoperative complications, readmissions, and total and component surgical episode costs.

Patients treated in IDS hospitals differed according to several characteristics, including race, admission acuity, and comorbidity. For each of the 4 procedures, adjusted rates for operative mortality, complications, and readmissions were similar for patients treated in IDS-affiliated compared with non-IDS-affiliated hospitals, with the exception that those treated in IDS-affiliated hospitals had fewer readmissions after colectomy (12.6% vs 13.5%, P = .03). Adjusted total episode payments for hip replacement were 4% lower in IDS-affiliated hospitals (P < .001), with this difference explained mainly by lower expenditures for postdischarge care. Episode payments differed by 1% or less for the remaining procedures.

The benefits of the IDSs observed for ambulatory care may not extend to inpatient surgery. Thus, improvements in the quality and cost-efficiency of hospital-based care may require adjuncts to current ACO programs.