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A Canadian comparison of data sources for coronary artery bypass surgery outcome 'report cards'

Ghali WA, Rothwell DM, Quan H, Brant R, Tu JV; the Steering Committee of the Cardiac Care Network of Ontario. Am Heart J. 2000; 140(3):402-8.

Background — Prior comparisons of administrative versus clinical data for creating coronary artery bypass graft (CABG) surgery outcome “report cards” are all from the United States and yield inconsistent conclusions regarding the validity of administrative data report cards. In this study, we compared 2 CABG surgery outcome report cards for Ontario, Canada: one derived from clinical data from the Cardiac Care Network of Ontario and one derived from administrative data from the Canadian Institute for Health Information.

Methods — Data from 4 fiscal years, 1992-93 through 1995-96, were used. The Canadian Institute for Health Information report card was derived from administrative data only. The Cardiac Care Network report card drew on prospectively collected clinical information that included variables such as left ventricular ejection fraction but also required linkages to the Canadian Institute for Health Information data for ascertainment of selected comorbidities and in-hospital mortality rates. Logistic regression models were used to calculate risk-adjusted death rates for each of the 9 hospitals performing CABG surgery in Ontario.

Results — The risk-adjusted death rates were quite similar between data sources for 7 of the 9 hospitals. For 2 hospitals, rather large absolute differences in adjusted death rates of 0.58% and 0.64% were seen between report cards. There was a strong correlation between data sources for risk-adjusted hospital death rates (intraclass correlation coefficient = 0.927, P <.001) and for rankings of adjusted hospital death rates (Spearman correlation coefficient = 0.828, P =.02).

Conclusion — These results from Ontario, Canada, reveal general similarities between administrative and clinical data report cards for CABG surgery. However, clinical data are likely needed if individual hospitals are to be publicly scrutinized in outcome report cards.

Keywords: Data evaluation Cardiovascular diseases Health care evaluation