Cost-Effectiveness of a Peer and Practice Staff Support Intervention | Page 3
Published Online: March 20, 2014
Christopher S. Hollenbeak, PhD; Mark G. Weiner, MD; and Barbara J. Turner, MD, MSED
There are several limitations to this study. CHD risk is based on predicted score, and we did not measure actual events. This is a common limitation of any trial to prevent CHD events, since few events can be expected over the short term. We used a CHD risk measure developed by D’Agostino and colleagues that is less commonly employed but offers the advantage of allowing us to assess risk of either a primary or a secondary CHD event.5 Also, as noted in the results from the clinical end points, the difference in CHD risk was not statistically significant. This is less of a concern for the costeffectiveness analysis since we are able to model the uncertainty in both the outcome and costs. In addition, because we did not directly measure utilities, we could not evaluate QALYs—a standard benchmark for cost-effectiveness—in the short term. This has 2 implications. First, it means that the within-trial results cannot be compared with other costutility analyses. And second, the usual thresholds for declaring an intervention cost-effective in terms of cost per QALY are in the range of $50,000 to $100,000. Since we do not report cost per QALY, decision makers must come to their own conclusions as to whether the intervention is cost-effective in the first 6 months, given the ICER. Finally, as noted earlier, the trial lasted only 6 months. But very few CHD events can be expected over such a short time period. We attempted to address these limitations by extrapolating the trial results using a Markov model. This has the advantage of providing QALYs, but is limited in that the results are modeled and not directly observed as they are in the within-trial analysis. The Markov model was also limited by the fact that its risk equations did not differentiate between primary and secondary CHD events for the 50 patients (20 cases and 30 controls) who had been previously diagnosed with coronary artery disease.
The threat of CHD looms large worldwide. A modeling analysis of the benefit of interventions to reduce this threat internationally found that targeting interventions to persons whose 10-year CHD risk is over 35% would avert 63 million disability-adjusted life-years worldwide.15 In our trial, participants had a 6-month risk of CHD of roughly 0.63%, which would likely be under that very strict threshold. We suggest that developed nations must consider supporting behavioral interventions that complement pharmacotherapy to reduce risk factors for CHD.
Author Affiliations: Departments of Surgery and Public Health Sciences, The Pennsylvania State University, College of Medicine, Hershey, PA (CSH); AstraZeneca Pharmaceuticals, 1800 Concord Pike CIC-523, Wilmington, DE (MGW); Department of Research, University of Texas Health Science Center, San Antonio and University Health System, San Antonio, TX (BJT).
Source of Funding: This study was funded by the Robert Wood Johnson Foundation. In addition, Pfizer contributed supplemental funding for the study. Drs Hollenbeak, Weiner, and Turner received salary support from these funds to complete the work.
Author Disclosures: Dr Hollenbeak reports receiving a grant from the Robert Wood Johnson Foundation, which funded this study. The other authors (MGW, BJT) report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.
Authorship Information: Concept and design (CSH, MGW); acquisition of data (JHN, MGW); analysis and interpretation of data (CSH); drafting of the manuscript (CSH); critical revision of the manuscript for important intellectual content (CSH, MGW); statistical analysis (CSH); administrative, technical, or logistic support (CSH).
Address correspondence to: Barbara J. Turner, MD, MSEd, REACH Center, University of Texas Health Science Center, 1 Technology Center, 7411 John Smith Drive, Ste 1100, San Antonio, TX 78229. E-mail: turner @uthscsa.edu.
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