John P.A. Ioannidis, MD
Potential Financial Conflicts of Interest: None disclosed.
Requests for Single Reprints: John P.A. Ioannidis, MD, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, University Campus, Ioannina, 45110, Greece; e-mail, firstname.lastname@example.org.
Ioannidis J.; Personalized Genetic Prediction: Too Limited, Too Expensive, or Too Soon?. Ann Intern Med. 2009;150:139-141. doi: 10.7326/0003-4819-150-2-200901200-00012
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Published: Ann Intern Med. 2009;150(2):139-141.
Genetic epidemiology has identified many common genetic variants that are associated with common diseases, and the list is growing monthly (1, 2). This success has boosted expectations for personalized genetic prediction. According to these expectations, genetic information can tell people about their risk for various diseases and which medications they should use or avoid. However, 2 articles in this issue (3, 4) suggest that this promise may be exaggerated and premature.
Paynter and colleagues (3) evaluated the predictive performance of rs10757274 for cardiovascular disease (CVD) in 22 129 white women. This gene variant has emerged from genome-wide association studies, and its association with CVD has been extensively and consistently replicated across many data sets (5). Although the authors confirmed that this polymorphism is associated with incident CVD risk, even after adjustment for other risk factors, no improvement in the prediction of CVD occurred. Adding the genotypic information to traditional risk factors—including family history—reclassified 2.6% of the women to different risk categories, but 63.4% of them were incorrectly reclassified. Knowing a patient's rs10757274 genotype would not help a clinician make better preventive or therapeutic decisions to reduce the future risk for heart disease.
Center for Clinical Quality & Safety, Hadassah University Hospital
February 1, 2009
Personalized medicine with self management
To the Editor:
Eckman et al showed genotyping is not cost-effective in the management of atrial fibrillation with warfarin (1). Whether genotyping reduces hemorrhage risk is based on limited evidence from three small trials. Using genotyping, four of 214 patients had major bleeding, as compared to seven of 215 patients with standard management (a difference not statistically significant).
By contrast, a systematic review of 14 randomized trials using self-management and self-monitoring of anticoagulation with warfarin, showed significant reduction of hemorrhage (2). With self-management, 34 of 1349 patients experienced major bleeding as compared to 55 of 1471 patients with standard management. Thromboembolic events and death were also significantly reduced by nearly 40%.
We recently showed feasibility of patient self-management training prior to hospital discharge, based on a simple educational intervention in an unselected population (J Clin Eval Pract, in press). In the intervention group, during the first three months post-discharge, INR fell within target range in 60% of tests compared to 40% or less in the control group (p<0.001). Patient knowledge and satisfaction were also higher in the intervention group. The material, described on our website (www.hadassah.org.il/departments/quality/coumadin), includes a brochure in four languages, a slide rule with operating instructions, and a kit for the family physician.
Empowerment of patients is effective in the management of chronic conditions (3). Beyond genetic typing, personalized medicine might benefit from considering patient literacy, preferences and participation. Market incentives for "low-tech" communication skills are less immediately apparent than those for "high-tech" genetic testing, but the former may not be less effective.
1. Eckman MH, Rosand J, Greenberg SM, Gage BF. Cost-effectiveness of using pharmacogenetic information in warfarin dosing for patients with nonvalvular atrial fibrillation. Ann Intern Med. 2009;150:73-83
2. Heneghan C, Alonso-Coello P, Garcia-Alamino JM, Perera R, Meats E, Glasziou P. Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet 2006;367:404-11
3. Chodosh J, Morton SC, Mojica W, Maglione M, Suttorp MJ, Hilton L, et al. Meta-analysis: chronic disease self-management programs for older adults. Ann Intern Med. 2005;143:427-38.
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