HIV diagnosed later in Africans in south London

Africans have their HIV diagnosed at a later stage than either white or Caribbean patients in the UK, according to a study conducted in south London and published in the April 1^st edition of Sexually Transmitted Infections. The investigators also found that, compared to both white and Caribbean patients newly diagnosed with HIV, Africans were more likely to be diagnosed as a hospital in-patient and less likely to perceive themselves at risk of HIV.

A separate study published in the April 2³ edition of The Lancet found that African and Caribbean men in the UK had high numbers of lifetime sexual partners and a high risk of sexually transmitted infection, with a need for culturally sensitive, targeted sexual health education campaigns.

Study background

In the UK the overwhelming majority of heterosexuals with HIV are of African origin, and after gay men, Sub-Saharan Africans are the group most affected by HIV in the UK. However, since 1995 there has been a significant increase in the number of new HIV diagnoses in the UK amongst individuals of Caribbean ethnic origin. The majority of these are in heterosexuals, but there is concern that stigma in Caribbean communities means that HIV contracted through sex between men is under-reported.

Earlier studies conducted in London have consistently shown that Africans infected with HIV are more likely to be tested with more advanced HIV disease, meaning that the significant reduction in HIV-related illness and death seen in the UK white population has not been seen to such as great extent in Africans. Little data is available on HIV amongst individuals of Caribbean ethnicity in the UK.

The south London boroughs of Lambeth, Southwark and Lewisham have significant African migrant and Caribbean populations. In 1998, 23% of all new HIV diagnoses in London were located in these boroughs, and just under a third of all new HIV cases in that year were in black patients. What’s more, in 2001 over a quarter of new HIV diagnoses made in individuals of Caribbean ethnicity involved residents of Lambeth, Southwark and Lewisham.

Investigators from King’s College Hospital and St Thomas’s Hospital in south London wished to establish if there were any ethnic differences in the demographics, stage of HIV infection at diagnosis, reasons for HIV testing, and location of HIV testing (as an in-patient or in a sexual health clinic) over a three year period in population including whites, Africans and Caribbeans.

A total of 494 HIV diagnoses made at the two hospitals between early 1998 and the end of 2000 were included in the investigators’ analysis. The majority of patients (270, 55%) were Africans, just over a third (179, 36%) were white, and 45 (9%) were Caribbean.

Study finds significant differences

“There were significant differences across the three main ethnic groups in HIV risk group, clinical and CD4 stage at diagnosis and reasons and site for HIV testing”, write the investigators.

Significantly more Africans (93%) were heterosexual compared to both Caribbeans (69%) and whites (21%, comparison p < 0.001).

Africans were significantly more likely to be tested and diagnosed because they had symptoms suggestive of HIV (37%), or as part of the national antenatal screening programme (21%), rather than because they perceived themselves to be at risk of HI V (41%). In contrast, only 20% of whites were diagnosed when symptomatic, and 5 % because of pregnancy screening, however, 72% tested because of perceived HIV risk. Similar figures were established for Caribbean (31% symptoms, 4% antenatal testing, 66% test because of risk).

Whites were overwhelming diagnosed in sexual health clinics (84%), as were Caribbeans (80%), however only 10% of Africans had their HIV diagnosed in this setting (p < 0.001). By contrast, significantly more Africans (23%) were diagnosed as a hospital in-patient than either Caribbeans (20%), or whites (10%, comparison p < 0.001).

Median CD4 cell count at diagnosis lower in Africans

Median CD4 cell count at the time of HIV diagnosis was highest amongst whites (358 cells/mm³, followed by Caribbeans (294 cells/mm³, and lastly Africans (223 cells/mm³). Consistent with this, 10% of white patients had an AIDS-defining illness at the time of HIV diagnosis compared to 21% of Africans, a statistically significant difference (p = 0.02). Although 18% of Caribbeans had an AIDS-defining illness at the time of diagnosis, the difference with whites was not statistically significant (p = 0.25).

Over the three years of the study, for whites there was a non-significant trend for an increase in CD4 cell count (323 cells/mm³ in 1998 to 402 cells/mm³ in 2000). Similarly for Caribbeans, there was a non-significant trend for an increase in CD4 cell count at diagnosis (232 cells/mm³ in 1998 to 333 cells/mm³ in 2000). For Africans, however, there was a non-significant trend for a fall in CD4 cell count from 242 cells/mm³ in 1998 to 175 cells/mm³ in 2000.

Amongst whites and Caribbeans there was also a non-significant increase in the proportion of individuals testing for HIV because of perceived risk. However, there was no change between 1998 and 2000 in the reasons for, or site of, HIV testing amongst Africans.

In multivariate analysis, the investigators established that independent predictors of a lower CD4 cell count at the time of HIV diagnosis were African ethnicity (p = 0.01), being in the heterosexual HIV risk group (p = 0.02), injecting drug use (p = 0.04), older age (p < 0.001), and diagnosis in 1998 against 2000 (p = 0.003). Further analysis revealed that African ethnicity was associated with a two-fold greater risk of diagnosis with a CD4 cell count below 200 cells/mm³ (odds ratio 1.96).

“Black Africans continue to present with more advanced HIV disease than whites or Caribbeans”, write the investigators, who conclude, “further educational campaigns designed to promote the uptake of HIV testing among black Africans and black Caribbeans will need to address the multiple barriers to testing, including misconception of risk, stigma, and ready access to testing.”

Sexual health

Data from the second British National Survey of Sexual Attitudes and Lifestyles published in The Lancet suggests that sexual behaviour and the incidence of sexually transmitted infections varies amongst the UK’s ethnic communities. The investigators found that African (nine) and Caribbean (nine) men had the highest number of median lifetime sexual partners, and Indian (two) and Pakistani (one) men the lowest. White men had a median of six lifetime partners. By contrast, white women had the highest median number of lifetime partners (five), followed Caribbeans (three), Africans (two) and Indians and Pakistanis (one).

A significant association was found between ethnic origin and a sexually transmitted infection in the previous five years. Sexually active African men and Caribbean men had the highest risk (odds ratio 2.95 and 2.74 respectively). Controlling for age, number of sexual patterns, homosexuality, partners from overseas, and the use of condoms at last sexual intercourse did not significantly affect these odds ratios.

However, the study also found that black ethnic groups had a high awareness of and uptake of sexual health and HIV testing services, with both African and Caribbean men and women being significantly more likely than other ethnic groups to have attended a sexual health clinic or report testing for HIV. The investigators conclude by calling for culturally appropriate services and behavioural modification and risk reduction strategies.