Preventative tuberculosis (TB) therapy can reduce death among patients on antiretroviral (ARV) treatment by about half, according to new research from South Africa.
Based on an observational study, researchers found that patients newly initiated on ARV treatment who had also been given Isoniazid Preventative TB therapy (IPT) had about a 50% lower risk of death after their first year of treatment than patients not given IPT. Isoniazid is a standard first-line TB drug that has more commonly been given as preventative therapy to HIV-infected patients not yet eligible for ARVs.
According to lead author Salome Charalambous, research director with the Aurum Institute, a South African health research NGO, the study provides much-needed evidence to back the effectiveness of IPT use for ARV patients.
"Until now, the use of IPT in combination with ARVs has been thought to reduce mortality but it had not been established," said Charalambous, adding that these assumptions were based largely on the small reductions in mortality found among HIV-positive people who had started IPT but not ARVs.
Charalambous said she expected the findings to be confirmed by early next year when two randomised controlled trials on the use of IPT within ARV programmes report their findings.
The study is one of several IPT-themed papers published in a supplement of the journal AIDS by the Consortium to Respond Effectively to the AIDS/TB Epidemic (CREATE) in anticipation of the expected 1 December 2010 release of new IPT guidelines by the World Health Organisation. Much of the research featured in the supplement comes from Aurum's ongoing Thibela TB study involving 80,000 gold miners, which is looking at whether high IPT uptake can help reduce new TB cases at community level.
TB remains one of the leading killers of HIV-positive people. About 70% of South African TB patients are co-infected with HIV.
South Africa introduced national IPT guidelines in 2002 that recommended IPT for people living with HIV, but discouraged health workers from giving it to ARV patients. Implementation has been poor and by March 2010, fewer than 1% of patients eligible to receive IPT were accessing it.
According to results of research also published in the AIDS journal supplement, the greatest barriers to IPT uptake in South Africa could be traced to health workers, many of whom were either unaware or unconvinced of IPT's benefits. Many were also deterred by the perceived difficulty of ruling out active TB infection in HIV-positive patients. Patients given IPT who have undetected active TB can develop resistance to Isoniazid, complicating treatment. Health workers also worried that the side-effects and additional pill burden for patients would discourage adherence.
"It's actually quite crazy that most clinicians will routinely prescribe multi-vitamins when there is no evidence [to support their therapeutic effect] but with IPT, where there is so much evidence, there's so much more worry," Charalambous told IRIN/PlusNews.
She added that the mandatory use of X-rays to diagnose TB, according to South Africa's 2002 IPT guidelines, could be a barrier as they may not be available everywhere. In reality, health workers could exclude at least 90% of active TB cases through sputum testing and symptom screening - asking patients if they are experiencing night sweats, a persistent cough or weight loss.
Few serious side-effects
Research by Alison Grant from the London School of Hygiene and Tropical Medicine, also included in the supplement, found that serious side-effects related to IPT were rare and largely tied to excessive alcohol consumption.
Charalambous said she hoped the research - and the new guidelines - would be enough to convert the unconverted, some of whom she said ranked among the country's most respected experts.
As part of a new push to scale up the use of IPT by South African Health Minister Aaron Motsoaledi, the government updated its IPT guidelines in June 2010. In response to some of the research produced by Aurum, the new guidelines no longer discourage the use of IPT in ARV patients and have done away with the mandatory chest X-rays and TB skin tests previously needed to start HIV-positive patients on IPT. - (IRIN/PlusNews, November 2010)