The use of rapid, point-of-care CD4 cell tests increases the chances that people diagnosed with HIV when using mobile HIV counselling and testing (HCT) services will be successfully linked to care, investigators from South Africa report in the online edition of the Journal of Acquired Immune Deficiency Syndromes.
“Our findings suggest that integration of POC [point-of-care] CD4 testing into mobile HCT programmes can increase the proportion of patients who accept the referral provided and make at least one visit to an HIV clinic,” write the authors.
By April 2010, some 13.5 million individuals in South Africa had been tested for HIV. The proportion of diagnosed patients who are successfully linked to HIV care is unknown. However, there is some evidence that this may be low. The average CD4 cell counts of patients at the time they start antiretroviral therapy is well below 200 cells/mm3. In early 201,1 the CD4 threshold for starting HIV treatment was increased to 350 cells/mm3. This will only be possible if people are diagnosed early and promptly linked to HIV care.
Mobile HCT can provide an opportunity for the early diagnosis of HIV. Investigators wanted to see if the provision of point-of-care CD4 tests to people who were diagnosed using this sort of service was associated with an increased likelihood of attending a first HIV follow-up appointment.
Point-of-care CD4 tests provide accurate CD4 cell counts in approximately 20 minutes.
The study population included 508 patients in the Gauteng Province who were diagnosed using the mobile HCT service in 2010. Their median age was 33 years, 60% were women and 40% reported a previous HIV test.
A total of 311 patients (61%) were offered a point-of-care CD4 test; the remaining 197 individuals (39%) were not. All the patients were given a follow-up appointment at an HIV clinic within eight weeks.
The investigators contacted patients via telephone to see if they attended their follow-up appointment. Approximately 62% of participants were successfully contacted.
In all, 59% of patients provided with point-of -care CD4 tests attended their follow-up appointment, compared to 47% of those who were not offered a rapid CD4 cell count.
After controlling for age, gender and HIV testing history, the investigators found that point-of-care testing was associated with a significant increase in the chances of attending a first follow-up appointment (RR = 1.23; 95% CI, 1.00-1.57).
Further analysis confirmed the association between point-of-care testing and successful linkage to care. This was restricted to the 263 patients who accepted an offer of a point-of-care test and received the result of this test. This on-treatment analysis showed that point-of-care CD4 cell testing increased the chances of patients attending a follow-up appointment by approximately one third (RR = 1.31; 95% CI, 1.04-1.64).
The investigators believe that the improved linkage to care seen with rapid CD4 cell testing “was large enough to merit consideration of adopting this intervention on a larger scale”.
People who received their results following rapid testing had a median CD4 cell count of 414 cells/mm3. Some 17% of patients had a CD4 cell count below 200 cells/mm3 (the then threshold for starting antiretroviral therapy), and 44% had a count below 350 cells/mm3, the new eligibility criterion for HIV treatment. Therefore 56% were not yet eligible for therapy and these people were somewhat less likely to attend a follow-up appointment than individuals with a CD4 cell count below 200 cells/mm3 (RR = 0.74; 95% CI, 0.55-0.97).
“The results…were largely encouraging, suggesting that integration of POC CD4 testing into routinely offered, mobile HCT services can increase uptake of HIV care,” comment the investigators. However, they note that their study left some important questions unanswered. These include reasons for accepting or declining point-of-care tests and the cost-effectiveness of the service. “The appropriate roles for point-of-care CD4 tests and other rapid, POC tests becoming available remain important research topics.”
Larson B et al. Rapid point-of-care CD4 testing in mobile HIV testing sites to increase linkage to care: an evaluation of a pilot program in South Africa. J Acquir Immune Defic Syndr, online edition. DOI: 10. 1097/QAI.0bo13e31825eec60, 2012.