Research Activities, August 2010: Outcomes/Effectiveness Research: Lower mortality rates after surgery at high-volume hospitals due to fewer complications and other factors

Outcomes/Effectiveness Research
Lower mortality rates after surgery at high-volume hospitals due to fewer complications and other factors

It is generally recommended that patients seek out high-volume hospitals to have complex surgeries, since greater volume means more experience by hospitals and surgeons. A new study did find that hospitals that performed a high volume of five complex surgical procedures had lower in-hospital mortality rates than low-volume hospitals. The lower rates were not just due to lower rates of surgery-related complications at high-volume hospitals. Instead, the researchers suggest that high-volume hospitals have a different patient mix than hospitals performing fewer of the procedures.

The new study looked at the association between surgical volume, complication rates, and mortality rates for five complex procedures: coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), electrical abdominal aortic aneurysm repair (AAA), pancreatectomy (PAN), and esophagectomy (ESO). High-volume hospitals for all of the procedures had significantly lower in-hospital mortality than lower-volume hospitals. High-volume hospitals had significantly lower odds for at least one complication following PCI, AAA, and PAN. Hospitals performing high volumes of CABG, AAA, and PAN were associated with significantly lower odds of respiratory complications.

The researchers also noted reductions in digestive complications (following PAN), hemorrhage or hematoma (following PCI), and bloodstream infection or sepsis (following PCI and PAN) compared with low-volume hospitals. However, the volume of procedures was not the sole factor influencing patient outcomes. Except for CABG, high-volume hospitals were more likely to have a greater proportion of elective or nonemergency admissions among patients undergoing complex surgeries than did low-volume hospitals. For PAN, high-volume hospitals tended to have younger patients with fewer coexisting conditions. The researchers found that patient characteristics alone were as useful as patient and hospital characteristics together in predicting outcomes.

The findings were based on data from the Nationwide Inpatient Sample of the Agency for Healthcare Research and Quality's (AHRQ's) Healthcare Cost and Utilization Project for the years 2000 through 2003. Finding pathways that lead to reduced mortality in high-volume hospitals, such as better procedures during the surgery and better postoperative care, is critical for identifying those processes that need to be improved in low-volume hospitals, suggest the researchers. Their study was funded in part by AHRQ (HS15009).

More details are in "Effect of meeting Leapfrog volume thresholds on complication rates following complex surgical procedures," by Veerasathpurush Allareddy, Ph.D., Marcia M. Ward, Ph.D., Veerajalandhar Allareddy, M.D., and others in the February 2010 Annals of Surgery 251(2), pp. 377-383.

Research Activities, August 2010: Outcomes/Effectiveness Research: Lower mortality rates after surgery at high-volume hospitals due to fewer complications and other factors