CDC looks at options to universal DOT
Are programs too dependent on it?
The first study evaluating the impact of directly observed therapy (DOT) during the past decade raises questions on whether it is overutilized, particularly when other adherence tools appear to work as well in some programs. But as health officials move toward TB elimination, DOT will remain a mainstay, particularly until better analysis identifies other options, say public health officials.
"The call for universal DOT provided an important challenge to the practices of public health departments that had done so poorly in managing TB," conclude the authors of the study, published in the July issue of the American Journal of Public Health.1 "But with the experience of the period between 1990 and 1994, it is clear that the simplicity of that call cannot serve as a singular guide to effective, budget-conscious TB control."
Researchers at Columbia University School of Public Health in New York City, lead by Ronald Bayer, PhD, evaluated the use of DOT and 12-month treatment completion rates between 1990 and 1994 in 25 cities and counties with 100 or more annual cases of TB. In 1993, the Centers for Disease Control and Prevention (CDC) began recommending the use of universal DOT for all programs that did not have 90% or more completion rates. During the study period, the median DOT rate increased from 16.8% to 49.4%. During the same period, median completion rates increased from 80% for the entire study population to 87%, the authors report.
While their study analysis of aggregate data was weakened by lack of detailed information, the authors conclude that their findings provide "an opportunity to reopen the discussion of TB policy, which may, in the mid-1990s, have moved to premature closure."
Is DOT the only game it town?
Widespread initiation of DOT has been cited as a major factor in the five-year downturn in TB cases in the United States. What the researchers tried to answer, however, was whether universal DOT has been necessary to achieve 90% or higher treatment completion rates. Their answer? Yes and no, depending on which TB program you are talking about.
Indeed, the authors found wide discrepancies in the use of DOT, and DOT utilization did not always correlate with high completion rates. In 1990, the study found that only one city that had completion rates of 90% or higher relied on universal DOT. Moreover, in three of seven jurisdictions, DOT rates were "negligible" - less than 20% in San Francisco.
Kenneth Castro, MD, director of the CDC's Division of TB Elimination, tells TB Monitor, that the study findings are not surprising. "We have known all along that places like San Francisco, for example, achieve the goal of curing or completing therapy in more than 90% of patients, and they tend to use selective DOT," he explains. "The problem with that is that you would almost need for every city to do its own assessment because all epidemiology is going to be local. What works in San Francisco may not extrapolated to New York City."
Until more detailed and specific information can provide guidance for how programs can reach 90% or higher completion rates without universal DOT, most programs will need to rely on the incremental use of DOT as a proven method, says Castro.
"What I would like to see is additional analysis before one prematurely moves away from DOT and starts trying alternative methods," he explains, "because the likely outcome in the absence of solid scientific basis is you are going to see gains lost if people prematurely start trying other methods."
Once scientific assessments are made, programs could then initiate pilot interventions based on the assessment to see if, indeed, alternative approaches work as well. "Once that is done, the data should speak for themselves," he adds.
In Massachusetts, where competition rates are high, DOT is one of several tools that is applied not universally but as needed, based on individual circumstances, says Edward Nardell, MD, TB control officer for the state. Using a decision tree to come up with the right tool, clinicians rely on various measures to get patients to complete their treatment regimens, including long-term hospitalization, he notes. For patients who have multidrug-resistant TB or are co-infected with HIV, DOT is usually the norm, he adds.
"We know that two-thirds of patients will [automatically] adhere to regimens, and we would like not to apply DOT to those folks if we can avoid it," he explains. "The problem that everyone will acknowledge is that we [clinicians] aren't very good about picking people out upfront who are going to be compliant. Still, that doesn't prevent you from making a good guess and correcting that action if patients do demonstrate any noncompliance."
Nardell, who peer-reviewed the article, says the study also brings to the forefront the ethical issues raised by universal DOT. "Frankly, I don't think too many of us would like to be told we have to have someone supervise our therapy - making one feel sort of guilty until proven innocent," he said, adding that Bayer is a strong supporter of DOT but is sensitive to its social as well as medical implications.
What are the factors that give Boston and other city TB programs the luxury of not having to depend on universal DOT? The answer is not entirely clear from this study. "In general, the locales that had especially effective TB control efforts, with completion rates of 90% or better, were no more likely in 1990 to have established robust programs to enhance completion rates (by providing additional services to drug users, the homeless, and the mentally ill) than less successful locales."
DOT in co-infected patients
One group of patients in whom compliance is particularly difficult is those co-infected with HIV and TB. Not only are HIV-positive patients burdened with difficult regimens, but protease inhibitors have problematic drug interactions with rifampin. As such, some clinics have experimented with the use of HIV/TB liaison nurses who coordinate follow-up care and help patients adhere to therapy.
In a poster presentation at the 12th World AIDS Conference in Geneva this summer, researchers at the University of Southern California Medical Center in Los Angeles described their successful use of DOT in co-infected patients through the help of a liaison nurse.
Six patients co-infected with HIV and TB were treated for TB for two months, followed by highly active antiretroviral therapy (HAART). One dose of HAART was observed on each of the five days when TB medications were administered. A community worker was responsible for organizing the medications and helping the patients with self-administration. DOT in this manner was highly effective, the authors noted.2
In another study setting involving 75 co-infected patients, the HIV/TB liaison nurse coordinated TB information from seven public health clinics. "Improved communication between TB and HIV has been enormously successful for improved medical care of co-infected patients," the authors conclude.3
References
1. Bayer R, Stayton C, Desvarieus M, et al. Directly observed therapy and treatment completion for tuberculosis in the United States: Is universal supervised therapy necessary? Am J Public Health 1998; 88:1,052-1,058.
2. Jones B, Rayos O, Silva V. Directly observed therapy of highly active antiretroviral therapy in patients with HIV and TB. Presented at the 12th World AIDS Conference. Geneva; July 1998. Abstract #60582.
3. Otaya M, Jones B, Currier J. HIV/TB liaison nurse in the HIV clinic. Presented at the 12th World AIDS Conference. Geneva; July 1998. Abstract #61/13247.
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