During a 12-week routine HIV testing intervention in an OPD in Durban, South Africa, nearly half of patients accepted HIV testing; the prevalence of HIV was 32.7%. A detailed survey of 720 test acceptors revealed that those at highest risk for a new diagnosis of HIV were unmarried men, patients aged 30–39 years, those who had not been tested before, and those with a low HIV knowledge score.
We found an interaction between gender and marriage as correlates of a new HIV diagnosis. Unmarried men were at the highest risk, nearly seven times that of married women, with unmarried women having nearly six times the risk of that of married women. In the current study, married people seem both more willing to be tested and more likely to be HIV negative. For provider-initiated testing in Botswana and traditional voluntary counselling and testing (VCT) in rural Uganda, HIV test acceptance was higher among married individuals [11
]. In a country-wide report from the Ministry of Health of Botswana, uptake of provider-initiated testing differed by gender; for example, uptake for women aged 15–19 years was 89.4% vs
. 75.6% for men [10
]. We found that unmarried men were most likely to be HIV-infected based on multivariate analysis, yet in other studies this is the group that were least likely to accept HIV testing [10
We also found that a significantly lower proportion of men had a perfect HIV knowledge score compared with women (8.9% vs
. 15.0%; P
=0.019). The role of knowledge about HIV as predictive of accepting HIV testing has been described previously in Africa [6
]. In rural Zimbabwe, knowledge of HIV was associated with VCT uptake in an adult cohort, and basic knowledge about prevention of mother-to-child transmission predicted uptake of routine HIV testing in antenatal clinics [6
]. Similar findings were noted in studies of HIV testing uptake in both Botswana and Nigeria [11
]. In our study of HIV test acceptors, patients with a high knowledge score were less likely to be HIV-infected, suggesting that HIV knowledge not only predicts willingness to accept testing, but also may be protective against acquiring HIV infection. In the African studies noted above, those with higher educational status were more likely to accept testing; in the current study, education level did not correlate with HIV test results [6
]. Thus, educational interventions targeting the general population to increase knowledge about HIV transmission and infection may prevent new infections, regardless of formal educational status. In the USA, low health literacy has been associated with HIV test acceptance of provider-initiated testing, but also with lower CD4 and higher viral loads among people living with HIV [17
We found that younger patients, particularly aged 30–39 years, were at high risk of having a new diagnosis of HIV during the routine testing intervention. This finding is consistent with the South African national antenatal survey which has documented an increasing prevalence of HIV among women in this age group over the last several years [19
]. In Botswana, the number of women tested in their 30s was lower than in the 20–29 year age group; however, this probably reflects an increased offer of testing for childbearing women attending antenatal clinics [10
]. Age in the 30s does not appear to be a strong predictor of declining HIV testing in Botswana, South Africa or Zimbabwe [10
], but this is a high-prevalence group which deserves particular attention when designing testing interventions.
Fewer than one-third of those found to be HIV-infected through routine HIV testing in this study underwent CD4 cell count testing at the HIV care site of the hospital within 3 months, suggesting a failure to follow-up, link to care and receive therapy. The only significant predictor of returning for a CD4 cell count was being employed. The low rate of undergoing a CD4 cell count, and the fact that patients with a salary were more likely to obtain a CD4 cell count, may both reflect the fact that patients were required to pay a fee for CD4 testing (80 Rand; ~US$11.00 in 2005). This hypothesis is supported by studies on several large cohorts in resource-limited settings that have shown that access to free HIV care correlates with obtaining a baseline CD4 cell count [21
]as well as retention in care at 6 months [21
]. Promoting linkage to HIV care through the offer of free baseline CD4 testing may improve access of HIV services in our setting. After the results of this study became available, McCord Hospital made CD4 cell counts available free of charge.
This analysis has several limitations. The surveyed population represents only half of the patients who accepted HIV testing during the study; this sample may not be fully representative despite efforts to survey every second patient to minimize bias. However, the patients surveyed did not differ significantly from tested patients overall with respect to age and gender. The decision not to survey all participants was made to allow the limited staff to focus their energies on counselling, education and HIV testing itself. The knowledge questions in the survey represent only a subset of a longer validated instrument [13
]; the subset was chosen based on its relevance to the study setting, but it has not been independently validated. In addition, the McCord patients pay a fee to receive care in the OPD, which may affect the generalizability of the results to fully government-subsidized hospitals in the South African public sector, where care is free of charge.
Nearly half of patients offered routine HIV testing in a high-prevalence OPD in South Africa accepted testing. Among surveyed patients, those with the highest rates of previously undiagnosed HIV included men, young and unmarried patients, those with no prior history of HIV testing, and those with poorer HIV knowledge. Unmarried men may be least likely to accept testing, but in our study this was the group with the highest risk of HIV infection; further studies to increase testing uptake should be directed at this group. Better interventions are needed to improve HIV knowledge and decrease HIV risk behaviour, particularly among men. Provision of CD4 cell counts free of charge to patients may improve linkage to care among patients newly diagnosed with HIV.