REGIONALIZATION OF HIGH RISK SURGERIES AND ITS IMPLICATION ON OUTCOME AND SURGICAL CARE SUPPLY REGULATION

Purpose:

The consistent empirical findings of a positive relationship between hospital surgical volume and outcome suggests a learning effect on the improvement of surgical practice – “practice makes perfect.”. The relationship provides a justification for concentrating surgical procedures in a limited number of high-volume hospitals (i.e., regionalization) as a way to improve surgical outcomes. In this study, we examine the degree of regionalization of 8 high-risk surgeries across states. Moreover, we optimize a statewide regionalization policy for those high-risk surgeries and assess its impact on in-hospital mortality and operating hospital capacity.

Method:

Our data are the 2003-2010 State Inpatient Database in 11 states. The 8 high-risk surgeries include repair of abdominal aortic aneurysm (AAA), aortic-valve replacement, coronary-artery bypass grafting (CABG), carotid endarterectomy, cystectomy, esophagectomy, lung resection, and pancreatectomy. For each surgery, we estimate a hospital-level learning curve to characterize the volume and in-hospital mortality relation. Next, using the curve, we solve best regionalization policy that minimizes in-hospital mortality. The gap between in-hospital mortality under existent patient referral pattern and that under best regionalization reflects regionalization degree of the surgery. We repeat the analysis across surgeries and states.

 

Result:

Regionalization of aortic-valve replacement varied the least across the 11 states (see Figure); its mortality gap between existent referral pattern and best regionalization ranged from 16.0% in New York state to 22.2% in California (6.2% difference). In contrast, regionalization of pancreatectomy varied the most across the 11 states (see Figure); its mortality gap between existent referral pattern and best regionalization ranged from 40.5% in Maryland to 66.5% in California (26.0% difference). Regionalization could avoid 16,719 deaths among 1,730,168 cases for the 8 surgeries in the 11 states during 2003-2010. Specifically, regionalization could avoid the most deaths (2,654 among 318,506 cases) for carotid endarterectomy and the least deaths (891 among 25,030 cases) for esophagectomy.  Across the 8 surgeries, observed operating hospitals were 4.5 (for CABG) to 21.0 (for lung resection) times greater than optimal numbers under best regionalization.

Conclusion:

Regionalization of high risk surgeries varies significantly in the US. Statewide regionalization has the potential to significantly reduce in-hospital mortality. From a mortality reduction perspective, there exists an overcapacity of caring hospitals for high risk surgeries.