title: Correlation between annual volume of cystectomy, professional staffing, and outcomes: a statewide, population-based study.
abstract: BACKGROUND
  The association between high procedure volume and lower perioperative mortality is well established among cancer patients who undergo cystectomy. However, to the authors' knowledge, the association between volume and perioperative complications has not been studied to date and hospital characteristics contributing to the volume-outcome correlation are unknown. In the current study, the authors studied these associations, emphasizing hospital factors that contribute to the volume-outcome correlation.
  
  
  METHODS
  Multiple-variable models of inpatient mortality and complications were developed among all 1302 bladder carcinoma patients who underwent cystectomy between January 1, 1999 and December 31, 2001 in all Texas hospitals. General estimating equations were used to adjust for clustering within the 133 hospitals. Data were obtained from hospital claims, the 2000 U.S. Census, and databases from the Center for Medicare and Medicaid Services and the American Hospital Association.
  
  
  RESULTS
  Complications were reported to occur in 12% of patients, 2.2% of whom died. Mortality was higher in low-volume hospitals compared with high-volume hospitals (3.1% vs. 0.7%; P < 0.001); mortality in moderate-volume hospitals was reported to be intermediate (2.9%). After adjustment for advanced age and comorbid conditions, treatment in high-volume hospitals was associated with lower risks of mortality (odds ratio [OR] = 0.35; P = 0.02) and complications (OR = 0.53; P = 0.01). Hospitals with a high registered nurse-to-patient ratio also had a lower mortality risk (OR = 0.43; P = 0.04).
  
  
  CONCLUSIONS
  Mortality after cystectomy was found to be significantly lower in high-volume hospitals, regardless of patient age. Referral to a hospital performing greater than 10 cystectomies annually is indicated for all patients. However, patients with poor access to a high-volume hospital may derive similar benefit from treatment at a hospital with a high-registered nurse-to-patient ratio. This finding requires further confirmation.
authors.affiliation: Section of Health Services Research, Department of Biostatistics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA. lelting@mdanderson.org
authors.forename: Linda S
authors.initials: LS
authors.lastname: Elting
authors.forename: Curtis
authors.initials: C
authors.lastname: Pettaway
authors.forename: B Nebiyou
authors.initials: BN
authors.lastname: Bekele
authors.forename: H Barton
authors.initials: HB
authors.lastname: Grossman
authors.forename: Catherine
authors.initials: C
authors.lastname: Cooksley
authors.forename: Elenir B C
authors.initials: EB
authors.lastname: Avritscher
authors.forename: Kamaldeen
authors.initials: K
authors.lastname: Saldin
authors.forename: Colin P N
authors.initials: CP
authors.lastname: Dinney
mesh_terms: D000328:Adult; D000368:Aged; D015653:Cystectomy / Q000009:adverse effects / Q000401:mortality / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008505:Medical Staff, Hospital; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011785:Quality Assurance, Health Care; D001749:Urinary Bladder Neoplasms / Q000601:surgery*