Abstract 113: Regional Variation In The Receipt Of Coronary Revascularization Following Diagnostic Catheterization In British Columbia

Abstract

Background: Differences in the management of coronary artery disease have previously been found to be partly attributable to non-clinical factors, but there have been few studies examining this issue in Canada. Variation in revascularization rates across regions of the province of British Columbia (BC) has been previously observed but not studied. The BC Cardiac Registry allows a unique opportunity to explore the factors that contribute to this variation and the associated clinical outcomes. Methods: All BC residents aged 20 years and older who received a diagnostic catheterization between 2008/09 and 2010/11 in one of five hospitals in the province with a catheterization laboratory were identified from the BC Cardiac Registry, a longitudinal clinical registry of all cardiac procedures performed in the province. Patients were followed to determine hospital level rates of revascularization (PCI or CABG) within 90 days of the diagnostic catheterization. Risk-adjustment was performed with a logistic regression model to determine whether the cathing hospital was an independent predictor of revascularization rates. All cause mortality rates following diagnostic catheterization were calculated and Cox regression was used to determine the effect of the cathing hospital on 1-year mortality. Results: The cohort included 32,585 diagnostic catheterization cases, of which 73.9% (24,076) received revascularization within 90 days. Unadjusted hospital rates ranged from 64.6% (2,730 of 4,224) to 83.8% (5,135 of 6,130). Among cases who received revascularization, the PCI:CABG ratios ranged from 3.1 to 4.7. The logistic regression model measuring the association between cathing hospital and the receipt of revascularization demonstrated significant hospital differences, despite controlling for demographic and clinical risk factors. The OR of receiving revascularization at hospital B compared to hospital A was nearly 3-fold (OR=2.8, 95% CI 2.6 - 3.1). There were also significant hospital differences after risk-adjustment in the receipt of PCI vs. CABG. Hospital C was more likely to treat patients with PCI (OR=1.3, 95% CI 1.2-1.5) compared to hospital A. Exploration of interaction terms found that hospital differences were significant among STEMI patients. The probability of mortality at 1 year following diagnostic catheterization ranged from 0.035 to 0.067 among hospitals, based on Kaplan-Meier estimation. Cox regression modeling revealed that there were significant hospital differences in 1-year mortality after adjusting for patient characteristics. Conclusions: There was substantial regional variation in revascularization practice among hospitals in the province of British Columbia, Canada. Identification of subgroups where variation in practices were significant, such as use of PCI vs. CABG among STEMI patients, offer opportunities for follow-up and quality improvement.