Global comparators project: international comparison of hospital outcomes using administrative data

Objective: To produce comparable risk-adjusted outcome rates for an international sample of hospitals in a collaborative project to share outcomes and learning.

Data sources: Administrative data varying in scope, format, and coding systems were pooled from each participating hospital for the years 2005-2010.

Study design: Following reconciliation of the different coding systems in the various countries, in-hospital mortality, unplanned readmission within 30 days, and "prolonged" hospital stay (>75th percentile) were risk-adjusted via logistic regression. A web-based interface was created to facilitate outcomes analysis for individual medical centers and enable peer comparisons. Small groups of clinicians are now exploring the potential reasons for variations in outcomes in their specialty.

Principal findings: There were 6,737,211 inpatient records, including 214,622 in-hospital deaths. Although diagnostic coding depth varied appreciably by country, comorbidity weights were broadly comparable. U.S. hospitals generally had the lowest mortality rates, shortest stays, and highest readmission rates.

Conclusions: Intercountry differences in outcomes may result from differences in the quality of care or in practice patterns driven by socio-economic factors. Carefully managed administrative data can be an effective resource for initiating dialog between hospitals within and across countries. Inclusion of important outcomes beyond hospital discharge would increase the value of these analyses.