Using volume criteria: do California hospitals measure up?

Many studies have demonstrated a significant relationship between high procedural volume and better outcomes. As the public becomes increasingly aware of this medical literature, consumer groups have collaborated with medical researchers to operationalize this body of evidence. One such organization, the Leapfrog Group, has proposed annual volume criteria for four operations: coronary bypass grafting (CABG), abdominal aortic aneurysm (AAA), carotid endarterectomy (CEA), and esophageal cancer resection (ECR). This study analyzes California hospitals within the context of these volume criteria.

Using the California inpatient database from 2000, we identified all CABG, AAA, CEA, and ECR operations performed at metropolitan hospitals. The volume of each of the four operations was tabulated by hospital and evaluated. Comparisons were made between academic and nonacademic hospitals.

Most hospitals in California did not meet Leapfrog's volume criteria. Only 2 hospitals of 287 (0.7%) met the volume criteria for the operations that it performed. Of the 71 (25%) hospitals that performed all four procedures, none met the volume criteria of all four procedures. In fact, only 10% of California hospitals performing these operations were high-volume hospitals based on Leapfrog's volume criteria. When comparing academic to nonacademic hospitals, academic hospitals performed more AAA operations than nonacademic hospitals (36 vs 12, P = 0.02). Although academic hospitals tended to have higher caseloads for CABG, CEA, and ECR, these did not reach statistical significance. Also, academic hospitals were more likely to be high volume for AAA (43.8% vs 7.0%, P < 0.01) and for ECR (23.1% vs 4.0%, P < 0.01).

California's hospital system is far from being regionalized. Although academic hospitals appear better positioned than nonacademic hospitals, the vast majority of all hospitals do not meet Leapfrog's volume criteria. As efforts to use volume as a proxy measure of quality gain momentum, hospitals and physicians will be forced to measure and report quality. As such, surgeons need to decide between accepting volume as an adequate measure of quality and developing other possibly more direct and reliable methods.