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Supervised Tuberculosis Preventive Therapy Works For Injection Drug Users

May 25, 2001

Supervised Tuberculosis Preventive Therapy Works For Injection Drug Users

 Spending more time and money up front to keep injection drug users with latent tuberculosis (TB) on strict, anti-TB regimens will improve patient outcomes and save money in the long run, according to a new study by Johns Hopkins researchers.

"The strategy, called directly observed preventive therapy (DOPT), results in more patients taking their treatment and fewer missed doses," says Richard E. Chaisson, M.D., professor of medicine at Hopkins and lead author of the study. "While supervised therapy costs more than routine care, the improved adherence rate should reduce active tuberculosis cases and thus, overall, lower costs."

Researchers at Johns Hopkins and the Baltimore City Health Department studied injection drug users because they make up a large proportion of those with TB and often have special problems adhering to multi-month TB preventive therapy. For example, although the inexpensive drug isoniazid is effective in preventing the development of TB, many patients without symptoms are less likely to take medications.

Appearing in the June issue of the American Journal of Medicine, the study tested three approaches to providing isoniazid preventive therapy to three groups of injection drug users, 100 per group. One group received DOPT twice weekly from a licensed practical nurse who watched them take the medication. Those in a so-called peer group took the medication by themselves and received peer counseling and education. The third group, after an initial counseling session, received standard care consisting of a monthly supply of pills. Doctors also randomly assigned individuals in each of the three groups to receive an immediate or deferred monthly $10 stipend for complying with the drug regimen. They then measured adherence to therapy by self-report or observation, testing urine for the drug, and, in a subset of participants, the frequency of medication container opening as determined by an electronic monitor in the cap.

The doctors found that DOPT increased the likelihood that individuals consumed all prescribed medication by roughly 60 percent compared with those in the standard therapy and peer groups. Immediate, rather than deferred payment of a monthly stipend also improved compliance.

"Improved adherence to preventive therapy means that tuberculosis will develop in fewer patients," says Chaisson. "Increasing the number of high-risk patients who take TB preventive therapy is a critical component of TB control and elimination." The new study, he comments, shows that DOPT can be a cost-effective way to prevent TB in injection drug users, a hard-to- reach population.

Tuberculosis is the second leading cause of death from an infectious disease. Worldwide, 2 million people die of TB annually, and 7 million to 8 million new TB cases are diagnosed each year. For more information on TB, visit the Hopkins TB Web site at

Other authors of the study from Hopkins are Grace Link Barnes, Judith Hackman, Supriya Metha, Linda Watkinson, Lucree Kimbrough, Solange Cavalcante and Richard Moore. The study was funded by the National Institute on Drug Abuse.

 The American Journal of Medicine, June 1, 2001, Volume 110, Number 8