title: Estimating surgical volume--outcome relationships applying survival models: accounting for frailty and hospital fixed effects.
abstract: This paper investigates the surgical volume-outcome relationship for patients undergoing hip fracture surgery in Quebec between 1991 and 1993. Using a duration model with multiple destinations which accounts for observed and unobserved (by the researcher) patient characteristics, our initial estimates show that higher surgical volume is associated with a higher conditional probability of live discharge from the hospital. However, these results reflect differences between hospitals rather than differences within hospitals over time: when we also control for differences between hospitals that are fixed over time, hospitals performing more surgeries in period t + 1 than in period t experience no significant change in outcomes, as would be predicted by the 'practice makes perfect' hypothesis. The volume-outcome relationship for hip fracture patients thus appears to reflect quality differences between high and low volume hospitals.
authors.affiliation: John M. Olin School of Business, Washington University in St Louis, MO 63130, USA. hamiltonb@wuolin.wustl.edu
authors.forename: B H
authors.initials: BH
authors.lastname: Hamilton
authors.forename: V H
authors.initials: VH
authors.lastname: Hamilton
mesh_terms: D000368:Aged; D005260:Female; D016330:Frail Elderly; D006620:Hip Fractures / Q000150:complications / Q000401:mortality / Q000601:surgery*; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D010351:Patient Discharge; D010818:Practice Patterns, Physicians' / Q000592:standards; D016016:Proportional Hazards Models; D011792:Quebec / Q000453:epidemiology; D013503:Surgery Department, Hospital / Q000592:standards* / Q000706:statistics & numerical data; D013514:Surgical Procedures, Operative / Q000401:mortality* / Q000706:statistics & numerical data*; D016019:Survival Analysis