Evolution of the surgeon-volume, patient-outcome relationship

Higher surgeon volume is associated with improved patient outcomes. This finding has prompted recommendations for increasing specialization and referrals to high-volume surgeons, yet their implementation in clinical practice has not been measured.

We performed cross-sectional analyses using 1999 and 2005 discharge information from the Health Care Utilization Project National Inpatient Sample to measure whether the number of procedures performed by high-volume surgeons increased over time. Procedures included those demonstrated to have strong surgeon volume-outcome associations in the literature. International Classification of Diseases, Ninth Revision codes were employed for colorectal procedures, esophagectomy, gastrectomy, pancreatectomy, thyroidectomy, coronary artery bypass graft surgery, and carotid endarterectomy. Bivariate analyses and hierarchical generalized linear models were employed to measure association between surgeon volume and length of stay (LOS) and mortality or complications.

There was a significant increase in the proportion of procedures performed by high-volume surgeons over time, with the most dramatic increases seen for gastrectomy (54%), pancreatectomy (31%), and thyroidectomy (23%). Having a procedure performed by a high-volume surgeon was associated with patient race and insurance status. Overall, unadjusted mortality and LOS were significantly lower for high-volume surgeons compared with low-volume surgeons in 1999 and 2005. In multivariable hierarchical generalized linear models, only differences in LOS by surgeon volume remained significant in both years.

The proportion of procedures performed by high-volume surgeons increased over a 6-year period, as evidence mounted in support of a surgeon volume-outcome association. Efforts are still needed to improve access among underserved subsets of the population and eliminate apparent disparities based on patient race and insurance status.