Abstract
Sir: In Scotland, around two-thirds of those with active hepatitis C virus (HCV) infection (37,500) are undiagnosed. 1 To enable these individuals to be identified cost-effectively, both SIGN and BASHH have published recommendations for testing high-risk groups. 2,3 Such higher risk individuals include intravenous drug users, HIV+ patients, receivers of blood products, needle–stick recipients and sexual partners of HCV- infected patients. The Edinburgh Genitourinary (GU) Medicine clinic protocol recommends screening of all the above, but in addition includes screening all men who have sex with men (MSM).
We performed a study reviewing HCV testing at the Edinburgh GU Medicine clinic. The study had three strands. Firstly, to audit the reasons for HCV antibody testing during one month (July 2008). Secondly, to detail the risk factors present in the HCV antibody positive population attending the clinic between 01 January 2003 and 31 July 2008 (a period of five years and seven months). Finally, to use the above data to do a basic evaluation of the cost-efficacy of screening for HCV in common clinic protocol risk-groups. This calculation was limited to data collected after 01 March 2005, the date the Edinburgh GU Medicine clinic HCV protocol was last updated.
Two hundred and forty-four individuals who had an HCV test at the Edinburgh GU Medicine clinic in July 2008 had their notes audited. The majority were men (201, 82%), white ethnicity (225, 92%) and homosexual (147, 60%). Two hundred and nineteen individuals (90%) were tested in accordance with the clinic protocol. Of the 25 individuals tested out-with clinic protocol, 13 had a sexual contact outside the developed world. One hundred and twenty-nine (53%) of the request population had MSM as a single-risk factor.
One hundred and one individuals had an HCV antibody positive test in the period 01 January 2003–31 July 2008. These individuals were also predominantly men (65, 64%) and white (93, 92%), but heterosexual (80, 79%). Seventy-five (74%) of the patients were PCR positive. Ninety-six (95%) of the HCV antibody positive patients had at least one clinic protocol risk factor; 25 (25%) had one risk factor only. History of intravenous drug use (IDU) was the most common risk factor, present in 73 (72%) individuals, the sole risk factor in 17. Twenty individuals had MSM as a risk factor, but only three had this as their sole risk.
A basic calculation was used to evaluate the cost-efficacy of the screening for HCV in-patient groups with single-risk factors of MSM and IDU activity, during the period 01 March 2005–31 July 2008. From lab data, the total number of HCV tests carried out at GU medicine during this period was 8201. Extrapolating from strand 1: an estimated 4338 (53%) of tests were for the single-risk factor of MSM, and 164 (2%) were for the single-risk factor of IDU. Despite this, among those testing HCV antibody positive within this period, there were 10 individuals with IDU risk only, versus three with MSM risk only. Valuing the marginal cost of adding an HCV antibody test to an STI screen as £10.42; around £15,000 needs to be spent to find a single HCV antibody-positive individual in a population with the sole risk of MSM activity (versus £170 to find a positive individual in an IDU population).
In the Edinburgh GU Medicine clinic cohort, HCV prevalence in MSM with no other risk factors was approximately 0.07%. This is lower than those found in previous studies of non-IDU MSM GU medicine attendees (0.6%). 4 This low estimated prevalence may be explained by our study selecting out MSM with additional risk factors (e.g. HIV infection). Our study therefore clearly shows that MSM GU medicine attendees with no other risk factors are not at any significant increased risk of HCV, and it is not cost-effective to routinely screen this population – a finding in keeping with the current BASHH guidelines on STI screening. 3