HIV experts question observed therapy in poor nations

A team of HIV researchers at the University of California CSF recommend against establishing directly observed therapy (DOT) as the model for the provision of HIV medications in resource poor countries. Writing in the June 13, 2003 issue of AIDS (now available online), the researchers challenge the assumption that poverty is a risk factor for non-adherence to anti-HIV regimens and cite the issue of stigmatisation.

"Without clear evidence that people in resource poor countries are less likely to adhere to HIV medication regimens than those in wealthy countries, it is difficult to argue for a delivery system that may compromise confidentiality and risk stigmatization," said co-author, Cheryl Liechty, MD, clinical fellow in UCSF's Division of Infectious Diseases.

The DOT model has been adopted in TB treatment in order to curb the spread of multi-drug resistant virus, but the authors note that observed pill-taking is just one element of a successful package, and has not been proven the superior form of TB treatment in all settings.

The authors question the assumption that adherence will be poorer in poor countries, citing two recent studies in Senegal and South Africa that found treatment adherence among impoverished participants ranged from 88 to 95 percent. This range compares to a 70 percent adherence rate measured in studies of HIV-infected individuals in wealthy countries.

"There is an assumption that all poverty acts the same. In this country, extreme poverty is often associated with issues of homelessness, mental illness and substance abuse. In resource poor countries, poverty is distributed relatively uniformly and is not linked to those issues that complicate adherence here," said the article’s co-author, David Bangsberg, MD, MPH, director of UCSF's Epidemiology and Prevention Interventions Center at San Francisco General Hospital Medical Center. Bangsberg's centre has pioneered the delivery of HIV medications to San Francisco's HIV-positive homeless population.

The authors note that DOT for tuberculosis therapy became a public health imperative to prevent emergence of drug resistance strains of TB and that the possibility of creating drug resistant strains of HIV is cited as a rationale for DOT for HIV.

"Data regarding adherence and resistance do not support this view. Low rates of adherence are less likely to create drug resistant HIV than high rates of adherence by patients who are unable to completely suppress viral replication. If DOT increased adherence, it could actually function to move patients into a window where resistant virus is selected. While DOT might improve clinical outcomes if it improves adherence, the failure to prevent drug resistance lessens the public health imperative to attempt to ensure adherence " said Bangsberg.

The possibility that DOT could reduce virus levels in infected individuals and thus make them less able to transmit HIV is also addressed by the authors. They observe that there is no evidence yet that DOT is superior to self-administered therapy for reducing transmission through treatment, and if it were proved to be so, that the discussion of HIV DOT should not be limited to resource poor countries.