Latest review of directly observed therapy paints the healthcare policy as ineffective, stirs existing controversy
By Ishani Ganguli | April 19, 2006
Directly observed therapy (DOT) -- a controversial technique in which health care workers or community volunteers watch patients swallow tablets -- does not have a significant impact on tuberculosis patients, according to a new report from The Cochrane Library. Still, DOT remains a central tenet of international recommendations for curbing the spread of treatment-resistant bacteria, and experts say they are unconvinced that clinicians should abandon the technique.
However, ?at the end of the day, it?s difficult to argue that DOT would be dramatically better than self-treatment,? Paul Garner, an author of the review and head of the International Health Research Group at the Liverpool School of Tropical Medicine, told The Scientist. ?It?s not a magical kind of approach that is central to ensuring adherence.?
Faced with a treatment regimen of at least six months, tuberculosis patients are particularly at risk of non-adherence, contributing to the spread of treatment-resistant bacteria, according to Dick Menzies, at McGill University in Montreal. To address this problem, the World Health Organization (WHO) recommends DOT as a central part of its five-part strategy for global TB control, introduced in 1994. Many programs use DOT, and experts say the strategy can help caretakers form positive relationships with their patients. But others argue that DOT is not cost-effective and demoralizes patients.
In the recent report, the authors reviewed ten randomized, controlled trials with a total of 3985 participants in low-, middle-, and high-income countries that directly compared DOT to self-administration of treatment. They found no statistically significant difference in the number of TB patients cured or the number of treatments completed. What?s more, they reported no evidence of DOT benefiting those who receive prophylaxis for a latent form of the disease. DOT can be seen as paternalistic and unnecessarily time-consuming, and clinicians should focus on other techniques, Garner said. ?[It] does tie up an awful lot of staff time if you?re directly observing every dose being taken,? he said.
However, experts say this latest report is not the last word on whether or not DOT works. Thomas Frieden, Commissioner of the New York City Department of Health, told The Scientist that 22 million people have been treated with DOT, and results from clinical trials do not match real-world data, which capture better how well the technique works. For instance, data gathered internationally outside clinical trials on relapse rates, death rates, and drug resistance show that ?DOT is an essential component of scaling up an effective program,? said Frieden, who has championed the strategy in New York City. In particular, public health programs in Texas, New York, and Baltimore have reported that implementing DOT has made ?drastic differences,? Frieden added.
Though DOT may be ?important,? said Garner, there likely has to be ?a whole menu of different things that are used to help ensure adherence, not just direct observation. For example, if somebody defaults on an outpatient appointment, get someone to chase the defaulter.? He has penned previous reviews about DOT, which have produced similar conclusions to the recent report.
Garner argued that by recommending DOT along with many other strategies to control TB -- such as meal tickets for the homeless and other incentives -- the WHO ?helped contribute to the confusion? about what DOT alone does to fight TB, perhaps causing some clinicians to overstate its importance. ?In the US, DOT programs?have loads and loads of other things they do for the patient besides the direct observation,? he said. ?It?s all those other things that are terribly important.?
?If it?s a bad program, DOT won?t be a magic bullet,? Menzies agreed. He said that he and his colleagues administer DOT on a case-by-case basis, making decisions based on risk factors -- such as IV drug use or psychiatric illness -- that suggest that a patient may not make his or her health a priority.
Frieden, however, said that, in his experience, adherence rarely correlates with patient characteristics, making it impossible to predict who needs DOT. As a result, his office continues to offer DOT to all New Yorkers with TB, and he estimates about 80% take it.
Links within this article
J. Volmink and P. Garner, ?Directly observed therapy for treating tuberculosis,? The Cochrane Database of Systematic Reviews, 2006
E. Russo, ?Turning back the tuberculosis tide,? The Scientist, May 23, 2005.
J. Volmink et al., ?Directly observed therapy and treatment adherence,? Lancet, 355:1345-50, April 15, 2000.