Opt-out HIV testing for acute medical admissions to UK hospitals works

Opt-out HIV testing for general medical admissions to hospital is feasible, cost-effective and leads to the identification of previously undiagnosed infections, the experience of a large south London hospital has shown.

In an article in the advance online edition of Sexually Transmitted Infections, investigators from Croydon University Hospital report a high uptake of opt-out testing among patients admitted to its acute medical unit. The implementation of universal screening identified 14 people who were diagnosed only because of the scheme; it also helped re-engage with care two previously diagnosed patients who had dropped out of care. Opt-out testing was highly cost-effective and the success of the policy was attributed to the commitment of staff in the acute medical unit, especially nurses.

“Our experience shows that HIV testing in general medical admissions as a policy is acceptable, feasible, sustainable and cost-effective,” comment the authors. “It has been delivered by existing medical staff alongside their other clinical duties, with time invested by HIV specialists for support, but no money spent by the hospital.”

Many people diagnosed with HIV in the UK now have a normal prognosis. However, HIV continues to cause significant levels of illness and death, and in most cases the reason is late diagnosis.

It is estimated that up to a quarter of all HIV cases in the UK are undiagnosed. Testing guidelines issued in 2008 recommend routine, opt-out testing for all general medical admissions to hospitals in areas where the diagnosed HIV prevalence in the local population is above 2 per 1000 individuals.Not all high prevalence areas have implemented these guidelines.

The local diagnosed prevalence in south London is approximately 5 per 1000 population, one of the highest in London. In July 2011 an opt-out testing policy was implemented at the acute medical unit at Croydon University Hospital. Patients aged between 16 and 79 were offered a standard HIV test unless they declined. The tests were administered by staff on the unit. All patients testing HIV positive were linked to HIV outpatient care.

Investigators wanted to assess the success of the opt-out testing policy. They therefore analysed data for the 21 months since its initial implementation.

There were 12,682 admissions to the unit between July 2011 and March 2013. A total of 4122 (33%) HIV tests were requested.  The testing rate increased from 33% during the first three months of implementation to 41% in the second three months (p < 0.005).

Implementation of the policy resulted in 20 (0.48%) HIV diagnoses. The patients had a median age of 41.5 years and most (14) were men.  Over a third (35%) had no clinical disease indicators of HIV infection at the time of screening.

“Their diagnoses would have been missed if it were only patients with indicator diseases who had been tested,” comment the researchers.

One person had confirmed primary HIV infection. His wife was in the 18^th week of pregnancy. Two years later, both she and her baby remain HIV negative.

Two newly diagnosed people had HIV-related kidney disease. Both started antiretroviral therapy, which normalised renal function.

One person was discharged from hospital before his HIV test result came back. Efforts to contact him are continuing. All the other patients were successfully linked to ongoing HIV care, and eleven have now started antiretroviral therapy.

It later became apparent that three of the diagnosed patients were already aware of their HIV infection. But two of these individuals had dropped out of follow-up at another treatment centre and were successfully re-linked to care after testing in the acute medical unit.

Overall, the patients identified nine contacts, seven of who were traceable. Six of these individuals were tested for HIV, and two were identified as HIV positive. One was already aware of her diagnosis; the other had a CD4 cell count of 155 cells/mm³ and has since started HIV therapy.

The total cost of the tests was £20,527, the equivalent of £1466 for each of the new HIV diagnoses. The policy incurred no extra costs apart from laboratory processing, funded by the local Healthcare Commissioning Board. “Positivity rate was 0.48%, approximately 5 times higher than the threshold prevalence for cost-effectiveness quoted in testing guidelines,” the authors note.

The researchers attribute the success of routine opt-out testing in this setting to close support during the early stages from members of the hospital's HIV team, ownership of the policy by Acute Medical Unit staff despite high staff turnover and the enthusiasm of nurses, who eventually took the lead in enforcing the policy in their unit.