title: Effect of hospital volume on outcomes of laparoscopic appendectomy for acute appendicitis: an observational study.
abstract: BACKGROUND
  This study investigated the effect of hospital volume on outcomes of laparoscopic appendectomy for acute appendicitis.
  
  
  METHODS
  In total, 30,525 patients who underwent laparoscopic appendectomy for acute appendicitis were referred to 825 hospitals in Japan from 2010 to 2012. We compared appendectomy-related complications, length of stay (LOS), and medical costs in relation to hospital volume. For this study period, hospitals were categorized as low-volume hospitals (LVHs, <50 cases), medium-volume hospitals (MVHs, 50-100 cases), or high-volume hospitals (HVHs, >100 cases).
  
  
  RESULTS
  Significant differences in appendectomy-related complications were observed among the LVHs, MVHs, and HVHs (6.9, 7.2, and 6.0 %, respectively; p = 0.001). Multiple logistic regression revealed that HVHs were associated with a lower relative risk of appendectomy-related complications than were LVHs and MVHs (odds ratio [OR], 0.84; 95 % confidence interval [CI], 0.74-0.95; p = 0.006). Multiple linear regression showed that HVHs were associated with shorter LOS and lower medical costs than were LVHs and MVHs. The unstandardized coefficient for LOS was -0.92 days (95 % CI, -1.07 to -0.78; p < 0.001), whereas that for medical costs was - $167.4 (95 % CI, -256.2 to -78.6; p < 0.001).
  
  
  CONCLUSIONS
  Hospital volume was significantly associated with laparoscopic appendectomy outcomes.
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, Fukuoka, 807-8555, Japan, amurata@med.uoeh-u.ac.jp.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Murata
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Mayumi
authors.forename: Keiji
authors.initials: K
authors.lastname: Muramatsu
authors.forename: Makoto
authors.initials: M
authors.lastname: Ohtani
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001062:Appendectomy / Q000009:adverse effects* / Q000191:economics; D001064:Appendicitis / Q000601:surgery; D002648:Child; D005260:Female; D017721:Hospital Costs; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume / Q000191:economics; D006801:Humans; D007564:Japan; D010535:Laparoscopy / Q000009:adverse effects* / Q000191:economics; D007902:Length of Stay / Q000191:economics; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D055815:Young Adult