Hospital volume and outcomes of cardiothoracic surgery in Japan: 2005–2009 national survey
To elucidate the relationship between hospital volume and cardiothoracic surgical outcomes in Japan using the annual survey data, obtained between 2005 and 2009, collected by the Committee for Scientific Affairs of the Japanese Association for Thoracic Surgery.
The relationship between hospital volume and 30-day mortality was analyzed using a logistic regression model. The empirical Bayes (EB) method was also used to stabilize any large variation resulting from a small sample size. Hospitals, whose lower limit of the EB mortality 95 % confidence interval was above the mean EB mortality of all hospitals, were defined as those with “inferior outcomes”. The surgical procedures analyzed were coronary artery bypass grafting (CABG: elective + emergency), elective CABG, emergency CABG, single-valve surgery, surgery for acute type A dissection, open heart surgery for newborns, open heart surgery for infants, surgery for lung cancer, and surgery for esophageal cancer.
There were large variations in 30-day mortality for all procedures, particularly in the lower-volume hospitals. There was a significant but weak inverse correlation between the hospital volume and the 30-day mortality rate for elective CABG, emergency CABG, single valve surgery, surgery for acute type A dissection, and lung cancer surgery. There was no correlation between hospital volume and the 30-day morality for open heart surgery for newborns and infants, and esophageal cancer surgery. After EB method adjustment, there was no hospital with inferior outcomes for conventional operations such as elective CABG, single-valve surgery and lung cancer surgery. The ratio of hospitals with inferior outcomes in more complex procedures was 1.8 % for open heart surgery for newborns, 0.8 % for open heart surgery for infants, and 0.2 % for esophageal cancer surgery.
There is a weak or no inverse correlation between the hospital volume and the mortality in cardiothoracic surgery in Japan. Most of the low-volume hospitals are not associated with inferior outcomes. The performance of the lower-volume hospitals should be carefully scrutinized using risk adjustment.
KeywordsHospital volume 30-day mortality Cardiac surgery Aortic surgery Lung cancer Esophageal cancer
The authors thank Ms. Etsuko Yamakoshi (Statcom Co. Ltd., Tokyo, Japan) for statistical analyses of the present study.
- 5.Nishida H, Yoshida E. Suggestions from non-pandering governmental health care policy groups: across the board 30 % cut of surgeon’s fee according to number of operation—pandering fool and disguised healthcare cost-cutting policy under fiscal crisis. Cardiovasc Med Surg. 2005;7:417–29.Google Scholar
- 15.Shahian DM, O’Brien SM, Filardo G, Ferraris VA, Haan CK, Rich JB, Normand SL, DeLong ER, Shewan CM, Dokholyan RS, Peterson ED, Edwards FH, Anderson RP. The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 1—coronary artery bypass grafting surgery. Ann Thorac Surg. 2009;88:S2–22.CrossRefPubMedGoogle Scholar
- 16.STS national database executive summaries. 2011.Google Scholar
- 19.Hughes GC, Zhao Y, Rankin JS, Scarborough JE, O’Brien S, Bavaria JE, Wolfe WG, Gaca JG, Gammie JS, Shahian DM, Smith PK. Effects of institutional volumes on operative outcomes for aortic root replacement in North America. J Thorac Cardiovasc Surg. 2012.Google Scholar
- 24.Kurlansky PA, Argenziano M, Dunton R, Lancey R, Nast E, Stewart A, Williams T, Zapolanski A, Chang H, Tingley J, Smith CR. Quality, not volume, determines outcome of coronary artery bypass surgery in a university-based community hospital network. J Thorac Cardiovasc Surg. 2012;143(287–293):e281.Google Scholar