State of evidence on the relationship between high-volume hospitals and outcomes in surgery: a systematic review of systematic reviews.

presented at the annual meeting of the German S Medicine and Prevention (DGSMP), Essen, Germany, S and the annual meeting of the German Network for Research (DNVF), Dresden, Germany, September 2012. Received October 29, 2012; Revised December 20, 2 December 20, 2012. From the Institute for Research in Operative Medicine, Fa School of Medicine, Witten/Herdecke University, Cologne Correspondence address: Dawid Pieper, MPH, Institute Operative Medicine, Faculty of Health, School of Me Herdecke University, Ostmerheimer Str 200, Building Cologne, Germany. email: dawid.pieper@uni-wh.de a 2013 by the American College of Surgeons Published by Elsevier Inc. COLLECTIVE REVIEW State of Evidence on the Relationship between High-Volume Hospitals and Outcomes in Surgery: A Systematic Review of Systematic Reviews Dawid Pieper, MPH, Tim Mathes, MHE, Edmund Neugebauer, PhD, Michaela Eikermann, MD In particular in surgical disciplines, many studies have been published on the volumeeoutcomes relationship since Luft and colleagues explained their theory of it. A lot of empirical work has shown differences in patient outcomes between high-volume hospitals (HVH) and low-volume hospitals (LVH) in favor of HVH. Mortality and survival have been explored the most in this debate. According to theory, superior outcomes in HVH can be explained by their structural characteristics (eg, teaching status or ownership) and a higher degree of experience. From this, it follows that the volumee outcomes relationship is likely to be most eminent in high-risk, low-volume procedures, such as pancreatectomy or esophagectomy. To improve patient outcomes, policy makers introduced minimum hospital volumes for surgical procedures. Among other quality criteria, accredited institutions performing bariatric surgery for Medicare patients must perform at least 125 operations per year. The Leapfrog Group has recommended annual hospital volumes for several surgical procedures. The European Society of Mastology claims for at least 150 newly diagnosed cases of primary breast cancer per year in specialized breast units. In Germany, minimum hospital volumes have been established for elected procedures. Although there seems to be a lot of evidence on the volumeeoutcomes relationship for several surgical procedures, there has also been a lot of criticism on the methodological quality of studies. Including methodologically flawed studies in systematic reviews can introduce bias in results when study quality is ignored. ociety of Social eptember 2012 Health Services