This represents one of the largest studies to date investigating factors related to antiretroviral uptake in an African setting. Through linkage of the population-based HIV surveillance data to the Hlabisa treatment and care program [16
] we have been able to examine in detail the factors associated with ART uptake in a rural area. Despite questions raised [21
] around the ability of ART programs in rural settings to reach vulnerable populations, we find remarkably little socio-demographic difference between the HIV positive populations accessing/not accessing ART. We do, however, find that physical distance from primary health clinics is a significant obstacle to accessing ART even when other socio-demographic factors are taken into account. Our data estimate ART uptake within 1 km of a clinic to be 25.9% (compared to 21.0% overall), falling rapidly with increasing distance from a clinic. This is despite an accelerated attempt towards decentralization of services in the area in question. Put more starkly, at distances of only 5 km from the nearest clinic, the odds of an HIV positive individual accessing ART are less than half those of an infected person living immediately next to a health facility holding all other factors constant. Contrary to expectation, no effect was seen due to level of education or measures of household wealth.
In the region in question, the provision of ART through primary healthcare facilities reduced the median distance that patients travel to access ART from 34.2 km to 3.1 km. This reduction in travel distances stands in comparison to estimates of 20 km or upwards used in early modelling of resource allocation [9
]. To achieve more uniform levels of ART uptake, consideration will have to be given to the cost-effectiveness of alternative ART delivery strategies (including, but not limited to, mobile treatment centres and more comprehensive home support services). Our results suggest that by making ART services more physically accessible, a relative increase in population ART uptake approaching 20% could be achieved.
The study area differs from many others in having rapidly decentralised ART delivery to primary care. We find that through this system it was possible to deliver ART to approximately 21% of the total HIV positive adult population over limited period of time within a relatively poor, rural area. This proportion accessing ART exceeds the target of 15% widely used in estimates of ART need at the beginning of roll-out [23
] (and could be termed >100% coverage). However, such targets are dynamic in areas where antiretroviral roll-out is maturing and new infection rates remain high [24
], and can differ between regions [25
] and for these reasons we focus here on the proportion of infected individuals accessing ART. Recently we have started to model the epidemic in this area using STDSIM [26
]. Initial estimates indicate that at the end of 2008, the 21% uptake of ART among the HIV positive population translates into a coverage figure of approximately 66% (Jan Hontelez, pers comm).
As well as the overall proportion of a population accessing ART, there are different notions of ethical treatment delivery. One principle highlighted in previous work is egalitarian equity (distribution of healthcare equally among groups that differ in socioeconomic circumstances) [8
]. The observation that the profile of household assets for those accessing ART does not differ significantly from that of the population infected with HIV, suggests that the ethical principle of egalitarian equity is being observed with regard to wealth. Locally, individuals in the poorest households are no less likely to utilize ART than those in wealthier ones (either univariately or holding all other factors constant). Contrary to recent reports from other settings suggesting large gender disparities in access to HIV treatment and care [28
], we show that HIV positive men are only slightly less likely to have accessed ART in comparison to women. However, this is not to say that significant sex differences do not exist, for example local data suggests that amongst individuals not yet eligible for HAART, retention rates within the program are poorer for men [30
] and that men are more likely to access ART programs with evidence of advanced disease [17
]. The significant differences in age observed are expected and a consequence of the time delay between HIV infection and progression to the point of ART eligibility which studies find to be quite consistent across sub-Saharan Africa [31
The speed with which services can be scaled-up has to be balanced against the quality of care it is possible to deliver and ultimately, the most important outcomes of widespread ART delivery will be the impact on population mortality and ongoing HIV transmission. Estimates from the study area suggest an important early impact on population mortality, but that HIV remains the leading cause of death [32
], and HIV incidence remains high [5
]. Local data suggests that in this early phase of ART delivery at least, outcomes for ART showed no evidence of decline [17
] and are broadly similar to those described elsewhere [33
], though such data is difficult to compare between sites [34
]. The development of services in the area of study was support by local NGOs with PEPFAR funding which is not the case in many other settings. Whether such outcomes can be maintained as services reach capacity is an important consideration, particularly as discussions begin around the possibility of reaching far higher levels of ART uptake, both in the implementation of new WHO treatment guidelines and as a means to decrease rates of HIV transmission [3
There are some limitations to the work presented here; the imperfect linkage between ART program and HIV surveillance data translates into relatively small false negative ratio of 6.5% (those on ART but not designated as such) in the individual-based risk factor analysis. This could result in a slight ascertainment bias of the results towards the null hypothesis. However, this could not create a spurious positive finding and would be unlikely to impact on any of the "null" findings (sex, education, household wealth, urban/rural locale) as none of these predictors bordered on statistical significance. We were not able to measure the small numbers of individuals accessing ART through non-governmental sources which might include family practitioners or other care providers in the area. During the period in question, the proportion of individuals receiving care in these settings was less than 5% of the total number. These factors mean that estimates of ART uptake provided here should be taken to refer to public sector delivery, the major ART source in this area. They are likely to be a lower estimate for the total population uptake of antiretroviral treatment overall, but that the underestimate is likely to be small. Such methodological issues will be important when comparing data from different settings and one interesting and unexpected finding of this study has been the large proportion (31%) of individuals receiving ART in the sub-district who are not normally resident in the area (migrants) but return frequently to be with their families and receive their ART. Failure to account for this could lead to inflated uptake estimates.
Strategies considering the wider use of antiretrovirals for preventing HIV transmission will require not only much higher levels of treatment uptake, but also high levels of VCT uptake. We have not attempted to address the overall uptake of VCT testing and knowledge of HIV status as individual data is not collected locally within government services. However, some minimum estimate of the numbers of HIV positive aware of their status can be derived from the number of different individuals accessing care (as determined by unique individuals attending for CD4 testing) before eligibility for ART compared to those receiving ART. Locally that ratio is approximately 1:1 suggesting a minimum bound for the proportion of the HIV positive population accessing care of at least 40%. The true level of VCT uptake is likely to be higher, to some extent for the reasons described above in relation to estimates of treatment uptake, but also because a significant number of individuals are probably lost from services prior to CD4 testing following a positive VCT result.