Cascade testing is tried and tested and cost effective

Wald et al suggest that screening children for high cholesterol at the time of immunisation, and then testing the parents of affected children, is an effective screening method for familial hypercholesterolaemia.¹ However, their paper does not address acceptability or cost effectiveness.

Earlier data from our group showed that universal screening was much less cost effective than cascade testing (family tracing from affected patients). A recent pilot study of cascade testing at five NHS trusts, funded by the Department of Health (www.fhcascade.org.uk), has confirmed cascading to be feasible, cost effective, and acceptable to both patients and clinicians.² Our recommendations to the department include that, because of the degree of overlap in cholesterol concentrations in affected and unaffected individuals, DNA testing is required to underpin a diagnosis of familial hypercholesterolaemia. The use of cholesterol testing as proposed by Wald et al will lead either to many false positive diagnoses in children, causing unnecessary anxiety, testing, and costs, or to true positives being missed because the cut-off point is set too high.

Around 15 000 patients with familial hypercholesterolaemia (of the estimated 100 000 cases) attend lipid clinics in the United Kingdom and cascading from these known cases should be the first approach as half of their first degree relatives will be affected.³ This has been extensively evaluated and should take priority for resources.⁴

However, finding more new patients will become important after the cascade work, which is estimated to find half of UK cases. The proposal to screen infants has clinical merit but would need to be piloted carefully. Approaches that circumvent using children as the primary contact warrant further investigation, for example, using data from general practice records, which recent data suggest to be feasible,⁵ or testing those presenting with myocardial infarction at an early age.