Unlinked Anonymous Survey of Genitourinary Medicine Clinic Attendees (GUM Anon Survey)

The GUM Anon survey is the only large scale survey in the UK to provide information on the prevalence of HIV, including undiagnosed HIV amongst GUM attendees. It uses the unlinked anonymous technique on left-over specimens taken for routine syphilis tests. 

The GUM Anon survey methodology is currently undergoing extensive review, under the guidance of an expert Steering Group.  New methodologies will be piloted and it is planned that a redesigned survey will be implemented in 2011.

Methodology

The GUM Anon survey uses the unlinked anonymous technique on left-over specimens taken for syphilis tests to measure the HIV prevalence amongst all GUM attendees, including those not having voluntary confidential HIV testing.  The unlinked anonymous technique involves removing all identifying information from the specimens.  Limited information on risk factors and whether voluntary confidential HIV testing was accepted is retained.  In 2009 this survey was operational in 13 GUM clinics across the UK (six in London and seven elsewhere in the UK).

GUM Anon Data

HIV Prevalence Overall prevalence of HIV infection, including undiagnosed HIV infection, and associated risk factors among GUM attendees

HIV test uptake and outcome the uptake of HIV testing in GUM attendees and the fraction of previously undiagnosed HIV positive GUM attendees remaining undiagnosed after a visit

GUM Anon Summary 2009 (update 2010) (PDF, 112 KB)

GUM Anon Supplementary Data Set 2009 (Update November 2010) (PDF, 110 KB)

HIV Prevalence

Figure 1: HIV prevalence of previously undiagnosed¹ HIV infection among attendees of sentinel GUM clinics across the UK, 2009

Data source: unlinked anonymous surveillance in 13 GUM clinics across the UK.

¹Previously undiagnosed HIV infection includes those diagnosed at the clinic visit as well as those who remained unaware of their infection, but excludes those that were diagnosed earlier.

•  Unlinked anonymous testing shows that of individuals attending sentinel sexual health clinics in 2009, 2.4% (119/4,925) of men who have sex with men (MSM) and 0.25% (180/70,971) of heterosexuals had a previously undiagnosed HIV infection. 
• The prevalence was slightly higher amongst heterosexual women (0.44% [85/38,483]) than heterosexual men (0.41% [95/32,488])
• Amongst heterosexuals, a higher prevalence was observed amongst those born in sub-Saharan Africa (1.3%, [54/4,134]) than those born in the UK (0.14% [74/52,183]) or elsewhere (0.34% [47/13,810]). 
• Similarly, the prevalence was higher in MSM born abroad (3.6% [40/1,114]) than those born in the UK (2.1% [77/3,759]).

HIV Test Uptake and Outcome

The data below refers to MSM and heterosexuals combined.  It excludes individuals with missing data, IDUs and others.

Figure 2: The proportion of GUM attendees receiving an HIV test and the fraction of HIV positive individuals remaining undiagnosed on leaving the clinic, sentinal GUM clinics, UK 2000-2009

Data source: unlinked anonymous surveillance in 13 sentinel GUM clinics, Health Protection Agency: 2009

• Overall, the proportion of attendees undergoing syphilis serology who received an HIV test has increased almost three-fold between 2000 and 2009, from 32% (21,625/66,869) to 95% (72,162/75,894). 
• Unlinked anonymous testing revealed that amongst individuals attending the sentinel GUM clinics with a previously undiagnosed HIV infection, the proportion receiving an HIV test has increased from 43% (190/440) in 2000 to 73% (219/299) in 2009.
• The proportion of HIV positive individuals leaving the GUM clinic undiagnosed reduced from 57% (250/440) in 2000 to 27% (80/299) in 2009.
• The pattern is similar for MSM and heterosexuals (Figure 2).
• Amongst heterosexuals, there is a lower uptake of HIV tests amongst those born in sub-Saharan Africa (91% [3,756/4,132]) compared to UK born heterosexuals (96% [50,168/52,183].  A higher proportion of HIV positive SSA born heterosexuals leave the clinic undiagnosed (30% [16/54]) than UK born HIV positive heterosexuals (22% [16/74]) or HIV positive heterosexuals born elsewhere (19% [9/47])

Summary of GUM Anon findings by Prevention Group 2008 (update 2009)

• Men who have Sex with Men (MSM)
• Black Africans and black Caribbeans
• Young Adults
  
• Injecting Drug Users
  

Annual Reports 2005/2010

HIV and STIs 2005/2010 Reports

Related Topics:

• HIV and Other Sexually Transmitted Diseases in the United Kingdom
• Other HIV Data 

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Last reviewed: 26 November 2010