[Three of the authors respond:]
We are chagrined by Michael Walsh's perception that we have been authors of a "nasty" article, but we are not unaware of the irony of this accusation. As practitioners who primarily care for seniors, we routinely advocate that CABG be performed in patients over 65 years of age, both for our own patients and at a policy level. What particularly concerns us about Walsh's comments is the potential for misunderstanding and misuse of descriptive costing information. We wish to emphasize most strongly that clinical policy is only indirectly related to descriptive costing information. Whether CABG should be performed in seniors depends primarily on 3 things: efficacy, effectiveness and cost-effectiveness. [1, 2] Cost-effectiveness expresses the relation between the cost and the clinical value of an intervention. Transplants, for example, are very costly, but they are usually cost-effective because they are extremely effective. A cost-effectiveness model that we are working on suggests that the same is likely to be true for CABG in seniors. [3] It is quite expensive but probably worth doing because it is very effective in prolonging life (for selected indications) and relieving angina.
So what is descriptive costing information good for? Costing studies allow us to identify categories of heavy resource utilization (e.g., drugs, investigations, inpatient care) and to direct future research efforts to areas in which the potential gain would be greatest. Our results indicate that the majority of the cost difference between older and younger patients was accounted for by the difference in the length of stay in the intensive care unit and on the ward. Identification of modifiable factors that contribute to longer stays for older patients may lead to interventions that decrease costs and also potentially improve clinical outcomes.
We strongly discourage the misuse of costing data alone to guide clinical policy. We hope that this descriptive costing study will not be fodder for the "cost-cutters," rather that it will promote further research that will lead to improvements in CABG for patients over 65.
Gary Naglie, MD
Murray Krahn, MD, MSc
Allan Detsky, MD, PhD
University Health Network and Mount Sinai Hospital; University of Toronto; Toronto Ont.