title: Influence of hospital volume on outcomes of laparoscopic gastrectomy for gastric cancer in patients with comorbidity in Japan.
abstract: OBJECTIVE
  Little information is available on the relationship between hospital volume and the outcomes of laparoscopic gastrectomy for gastric cancer in patients with comorbidity. This study aimed to investigate the influence of hospital volume on patient outcomes of laparoscopic gastrectomy for gastric cancer in patients with comorbidity using a national administrative database.
  
  
  METHODS
  A total of 5941 comorbid patients treated with laparoscopic gastrectomy for gastric cancer were referred to 741 hospitals in Japan. We collected patients' data from the administrative database to compare laparoscopy-related complications, in-hospital mortality, length of stay (LOS), and medical costs during hospitalization in relation to hospital volume. Hospital volume was categorized into two groups: low (<40 cases in 3 years; n = 4111) and high (≥ 40 cases; n = 1830).
  
  
  RESULTS
  There were no significant differences between the groups in laparoscopy-related complications and in-hospital mortality (p = 0.684 and p = 0.200, respectively). However, significant variations in mean LOS and medical costs were observed between hospital volume categories (26.1 days vs. 20.2 days and 16,163.9 US dollars vs. 14,345.9 US dollars, respectively; p < 0.001). Multiple linear regressions revealed that higher hospital volume was significantly associated with shorter LOS and lower medical costs during hospitalization. The unstandardized coefficient for LOS was -4.62 days (95% confidence interval = -5.63--3.60, p < 0.001), whereas that for medical costs was -1424.1 US dollars (95% confidence interval = -1962.5--885.6, p < 0.001).
  
  
  CONCLUSIONS
  Hospital volume was significantly associated with a decrease of LOS and medical costs of comorbid patients undergoing laparoscopic gastrectomy for gastric cancer.
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan. Electronic address: amurata@med.uoeh-u.ac.jp.
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Murata
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Muramatsu
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Ichimiya
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Fujino
authors.affiliation: Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsuda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease / Q000401:mortality*; D015897:Comorbidity; D017046:Cost Savings / Q000191:economics; D005260:Female; D005743:Gastrectomy / Q000191:economics; D017052:Hospital Mortality; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan; D010535:Laparoscopy / Q000191:economics; D007902:Length of Stay / Q000191:economics / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000191:economics / Q000209:etiology* / Q000401:mortality*; D013274:Stomach Neoplasms / Q000150:complications / Q000191:economics / Q000401:mortality / Q000601:surgery*
keywords: comorbidity; gastric cancer; hospital volume; laparoscopic gastrectomy; outcomes