HIV seroprevalence in a London same-day testing clinic

Risk behaviors and HIV incidence among repeat testers at publicly funded HIV testing sites in San Francisco

OBJECTIVE

More than 25% of HIV tests are for individuals who have previously been tested. To characterize repeat testers, we 1) estimated the seroincidence of HIV infection, stratified by risk behavior, and examined the association between 2) testing rates and risk level and 3) repeat testing and tester characteristics.

METHODS

Records from HIV counseling and testing (C&T) sites were reviewed. Seroincidence was estimated by linking results of current test with date of last reported HIV negative test. A risk hierarchy of behaviors was created. Repeat testing rates were calculated for each risk level strata. Multivariate models explored the association of repeat testing with tester characteristics.

RESULTS

The HIV seroincidence among repeaters was 1.3 per 100 person-years (range 0.7-7.0 per 100 person-years). The high-risk level subject had a repeater rate of 92%, with 5.3 tests/person and was more likely (odds ratio = 4.96, 95% confidence interval 3.8-6.5) to have tested two or more times, compared with those in the low risk group.

CONCLUSION

The highest users of repeat testing are those who are practicing the highest risk behaviors and have the highest incidence of HIV. This suggests that prevention messages should be modified to more explicitly address the behaviors that are putting individuals at high risk for HIV.

Ten-year trends in CD4 cell counts at HIV and AIDS diagnosis in a London HIV clinic

OBJECTIVE

To examine temporal trends (1986-1996) in the CD4 cell count at first HIV-1 positive test and initial AIDS diagnosis, and the influence of selected patient characteristics and treatment factors on these trends.

DESIGN

A retrospective clinic-based study.

SETTING

Three hospital-based clinics in West London.

PATIENTS

A group of 5921 adult HIV-1-seropositive persons and 2835 reported patients with AIDS over a 10-year period from 1 January 1986 to 1 October 1996.

METHODS

The CD4 cell count at HIV diagnosis (CD4HIV) was defined as the nearest CD4 cell count to within 2 months of HIV diagnosis; and the CD4 cell count at AIDS diagnosis (CD4AIDS) as the last CD4 cell count in the two months prior to the development of AIDS. Simple and multiple linear regression analysis were used to examine the influence of selected covariates on CD4HIV and CD4AIDS.

RESULTS

The percentage of patients with an available CD4HIV and CD4AIDS increased from less than 5% in 1987 to 53% and 40%, respectively, in 1990, and 79% and 48%, respectively, in 1996. Patients with a missing CD4HIV or CD4AIDS were younger and less likely to have received antiretroviral therapy or prophylaxis for Pneumocystis carinii pneumonia (PCP). There was no significant change in CD4HIV over a 10-year period (median 334 x 10(6) cells/l), but a lower CD4HIV was associated with older age at presentation and injecting drug use. There was a delay in the onset of clinical AIDS, with a fall in the median CD4AIDS value from 99 x 10(6) cells/l prior to 1987, to 58 x 10(6) cells/l in 1990, 68 x 10(6) cells/l in 1994 and 60 x 10(6) cells/l in 1996; this decline in onset was seen for PCP as well as for cytomegalovirus and atypical mycobacterial infections. At all time periods, a lower CD4AIDS was associated with combined use of antiretroviral therapy and PCP prophylaxis. After adjustment for use of antiretroviral therapy and PCP prophylaxis prior to AIDS diagnosis, year of diagnosis was no longer associated with CD4AIDS. There was a significant trend towards an improved survival following AIDS diagnosis from 20.1 months prior to 1988, to 20.3 months (1989-1990), 21.0 months (1991-1992) and 22.1 (1993-1994) (P < 0.0005).

CONCLUSIONS

The observed decline in CD4AIDS value was related to the introduction of antiretroviral therapy in 1988, and PCP prophylaxis in 1989. Temporal changes in the CD4 cell count at HIV and AIDS diagnosis among different demographic groups can provide insights into the changing natural history of the HIV epidemic and access to medical care. We recommend monitoring of the CD4 cell count at new HIV and AIDS diagnosis and at initiation of antiretroviral therapy as additional measures in national HIV/AIDS surveillance.

Screening for sexually transmitted diseases in an HIV testing clinic; uptake and prevalence

OBJECTIVE

To estimate the prevalence of sexually transmitted diseases (STDs) and the acceptability of STD screening among people seeking an HIV antibody test in an established free standing HIV testing clinic.

DESIGN

A 9 month period prevalence study conducted between August 1993 and April 1994.

SETTING

The Same Day Testing Clinic (SDTC) for HIV antibodies at the Royal Free Hampstead NHS Trust Hospital, London.

SUBJECTS

242 males and 160 females attending the Same Day Testing Clinic.

OUTCOME MEASURES

The prevalence of STDs including gonorrhoea, chlamydia, syphilis and hepatitis B and the percentage of clinic attenders accepting an STD screen.

RESULTS

Of those invited to take part in the study 69% of the males (242/350) and 59% (160/269) of the females agreed to be screened although for a variety of reasons not everyone agreed to a full screen. Two cases of untreated syphilis, no cases of gonorrhoea and six cases of chlamydia were detected. Four people had active, previously undiagnosed herpes while three had genital warts. Evidence of previously unknown hepatitis B infection was found in 26 people. Despite a high level of previous contact with genitourinary medicine services, uptake of hepatitis B vaccination among those homosexual men eligible for immunisation was low (28%; 23/83). Nine (4%) of the males, but none of the females screened for STD were found to be HIV antibody positive.

CONCLUSION

Among people seeking an HIV antibody test in an established free standing HIV testing clinic, the prevalence of acute STDs was low. However, evidence of previously undiagnosed hepatitis B infection was found in a number of subjects and uptake of vaccination among those most at risk had been low. While opportunistic screening for STD was acceptable to almost two thirds of HIV testing clinic attenders, a substantial minority nonetheless declined this offer. Selective STD screening could be offered to those people seeking an HIV test who report never having been screened before, as both cases of positive syphilis serology and all those of chlamydia were in people who had not previously been screened. All those at risk for hepatitis B infection should be encouraged to establish their infection status and be immunised where appropriate.