Comparing invasive and noninvasive management strategies for acute myocardial infarction using administrative databases

Pilote, Louise; Beck, Christine A.; Eisenberg, Mark J.; Humphries, Karin; Joseph, Lawrence; Penrod, John R.; Tu, Jack V.

doi:10.1016/j.ahj.2007.09.016

« Previous Next »American Heart Journal
Volume 155, Issue 1 , Pages 42-48, January 2008

Comparing invasive and noninvasive management strategies for acute myocardial infarction using administrative databases

Louise Pilote, MD, MPH, PhD
- Division of Clinical Epidemiology, McGill University Health Centre, Montreal, Quebec, Canada
- Reprint requests: Louise Pilote, MD, MPH, PhD, Division of Clinical Epidemiology, McGill University Health Centre, 687 Pine Avenue West, Montreal, Quebec, Canada H3A 1A1.
Christine A. Beck, MD, MSc
- Division of Clinical Epidemiology, McGill University Health Centre, Montreal, Quebec, Canada
Mark J. Eisenberg, MD, MPH
- Divisions of Cardiology and Clinical Epidemiology, Sir Mortimer B. Davis–Jewish General Hospital, Montreal, Quebec, Canada
Karin Humphries, MBA, DSc
- University of British Columbia, Vancouver, British Columbia, Canada
Lawrence Joseph, PhD
- Division of Clinical Epidemiology, McGill University Health Centre, Montreal, Quebec, Canada
John R. Penrod, PhD
- Division of Clinical Epidemiology, McGill University Health Centre, Montreal, Quebec, Canada
Jack V. Tu, MD, PhD
- Institute for Clinical and Evaluative Sciences, Sunnybrook and Women's College Health Science Centre, University of Toronto, Toronto, Ontario, Canada

Received 4 April 2007; accepted 9 September 2007.

Purpose

The aim of this study was to compare outcomes after acute myocardial infarction between regions with low and high catheterization access.

Methods

Observational study using administrative databases of patients with acute myocardial infarction in provinces with low (Ontario) and high (Quebec and British Colombia) access to invasive cardiac procedures (ICP, n = 141718). Using instrumental variables to control for confounding, effectiveness of treatment was measured on 1-year mortality among marginal patients (patients for whom treatment is discretionary and highly dependent on access to ICP).

Results

The ICP approach was associated with overall decreased mortality (−11%, 95% CI −13% to −8%) with statistically significant reductions in low-access regions (−16%, 95% CI −21% to −10%). High-access regions (QC −8%, 95% CI −19% to 4%) (BC −2%, 95% CI −12% to 7%) exhibited smaller marginal benefits.

Conclusion

The invasive approach benefits all marginal patients, with greater benefits in regions of lower access, indicating a threshold of availability above which further mortality benefits are negligible.