Opt-out testing increases HIV counselling and testing rates in South African TB clinics

This article is more than 16 years old. Click here for more recent articles on this topic

In patients presenting with tuberculosis in South African clinics, the use of opt-out HIV testing significantly increased the proportion of patients counselled and tested for HIV, as compared to standard-practice voluntary testing, according to a randomised study reported in the June 1st issue of the Journal of Acquired Immune Deficiency Syndromes. However, the number of patients tested remained relatively low, and the effects on subsequent care were slight.

In sub-Saharan Africa, a high proportion of people with tuberculosis (TB) are also infected with HIV, and TB is often the first clinical presentation of HIV disease. Although HIV testing for TB patients is recommended by global and South African guidelines, the number of people actually tested is often small. Under voluntary HIV counselling and testing, patients are not tested by default; they must explicitly "opt in" to receive counseling and testing.

In "provider-initiated" or "opt-out" testing, patients retain the right to refuse to be tested, but receive HIV counselling and testing unless they explicitly opt out. Opt-out testing has been recommended in World Health Organization and UNAIDS policies. Although it should have the potential to increase the number of people tested, and has proven highly acceptable in some African settings, wider data on its effectiveness in Africa have not been available.

Glossary

p-value

The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

pulmonary

Affecting the lungs.

 

referral

A healthcare professional’s recommendation that a person sees another medical specialist or service.

transmission cluster

By comparing the genetic sequence of the virus in different individuals, scientists can identify viruses that are closely related. A transmission cluster is a group of people who have similar strains of the virus, which suggests (but does not prove) HIV transmission between those individuals.

representative sample

Studies aim to give information that will be applicable to a large group of people (e.g. adults with diagnosed HIV in the UK). Because it is impractical to conduct a study with such a large group, only a sub-group (a sample) takes part in a study. This isn’t a problem as long as the characteristics of the sample are similar to those of the wider group (e.g. in terms of age, gender, CD4 count and years since diagnosis).

In this "cluster-randomised" study, 20 medium-sized South African TB clinics were randomised to provide one of two HIV testing interventions to newly presenting TB patients: voluntary, opt-in HIV testing (the default, and control group), or provider-initiated, opt-out testing (the experimental intervention). The clinics were chosen to be geographically and demographically representative of the 44 primary health clinics in the district in and around Port Elizabeth, Eastern Cape Province, South Africa.

A total of 1072 adults were newly registered as TB patients in the 20 study clinics between August and November, 2005. Of these, 754 (70%) met study criteria and were enrolled (the remainder moved out of the area, died, or did not have complete data). In the control clinics, there were 352 patients: 194 male (median age, 55) and157 female (median age, 45), 89% of whom had pulmonary TB (extrapulmonary TB patients were also included). In clinics randomly assigned to implement provider-initiated HIV counselling and testing (the "opt-out clinics"), there were 402 patients: 238 male (median age, 59) and162 female (median age, 41), 81% of whom had pulmonary TB.

The primary study outcome was the percentage of newly registered TB patients who received HIV counseling and testing, as compared between the two strategies. The opt-out strategy was more successful: in the opt-out clinics, 20.7% (73/352) patients received HIV counselling versus 7.7% (31/402) in the control clinics (p=0.011), and 20.2% (n = 71) versus 6.5% (n = 26) underwent HIV testing respectively (p=0.009).

Out of patients who actually received HIV tests, the proportion of HIV-positive test results was similar in the intervention and control arms (36% vs. 43%). However, due to the greater proportion of patients tested, opt-out clinics identified a higher proportion of patients as HIV-positive overall: 8.5% versus 2.5% in control clinics (p=0.044).

Disappointingly, however, the effects on treatment and care after diagnosis appeared to be minimal. The numbers of patients with a positive HIV test who were prescribed cotrimoxazole or referred for HIV care were small (less than 40% in either arm) and did not differ significantly between study arms.

The researchers concluded that "the use of an opt-out [HIV testing] strategy was associated with significantly higher HIV counselling and testing rates … but the overall proportion of those counseled and tested after training in the opt-out approach remained unacceptably low at only 21%." These results illustrate that "although instituting a strategy of provider-initiated counseling can increase rates of HIV counselling and testing, it is clearly not sufficient. Additional interventions and resources will surely be required to attain high levels of HIV testing referral into HIV care for TB patients in settings such as [these]."

Reference:

Pope DS et al. A cluster-randomized trial of provider-initiated (opt-out) HIV counseling and testing of tuberculosis patients in South Africa. J Acquir Immune Defic Syndr 2008;48:190–195.