June 22nd, 2011
JAMA: Skeptical Perspectives on Consumer Cardiac Tests and Vitamin D
Two commentaries published in JAMA offer skeptical perspectives on the roles of direct-to-consumer (DTC) cardiac tests and vitamin D in cardiovascular health.
In the first commentary, Kimberly Lovett and Bryan Liang write that DTC screening tests “likely pose more risk than benefit to patients,” and point out that for companies selling these tests there is no requirement “for full disclosure in advertising, informed consent, pretest evaluation, or posttest counseling.” Some screening tests, including tests for carotid artery stenosis, peripheral artery disease, atrial fibrillation, and abdominal aortic aneurysm, are not recommended for most people by organizations like the USPSTF and the ACC/AHA. Other tests, like CRP, lipid tests, and coronary calcium, have received limited endorsements, but only in carefully selected patients, the authors write.
They recommend that the FDA regulate consumer screening tests, that the companies provide pretest consultation with a qualified professional, and that DTC tests be included in the FDA Medwatch database.
In the second commentary, Sue Shapses and JoAnn Manson, who served on the Institute of Medicine committee on vitamin D, explain why the role of vitamin D in heart disease, stroke, hypertension, and diabetes played only “an inconsequential role in determining the population needs for vitamin D” in the recent IOM report.
Shapses and Manson acknowledge the “biological plausibility for a role of vitamin D in the prevention of cardiovascular disease and diabetes” but, citing deficiencies in both observational and randomized evidence, they conclude that “the evidence from available research is inconsistent, inconclusive as to causality, and not sufficient to inform nutritional requirements.” Several ongoing randomized trials may provide better evidence within 5 to 6 years, they write.