The resurgence of tuberculosis (TB) in the United States in the 1980s and early 1990s has been well documented. This problem was particularly severe in cities such as New York where the TB case rate nearly tripled over a 15-year period from the late worsening social and economic conditions, most

notably homelessness. In fact in one study of 224 1970s to the early 1990s. Among the factors contributing to this resurgence were the HIV epidemic, the decline in funding for TB control programs, and worsening social and economic conditions, most notably homelessness. In fact in one study of 224 consecutive patients with TB admitted to a large city public hospital, 68% were homeless or lived in an unstable housing situation. Of these, 178 were discharged with anti-TB therapy, 89% of which were subsequently lost to follow-up and did not complete treatment. Failure to complete treatment not only leads to morbidity and mortality in the individual patient but also to the spread of the disease to others in the community. In addition, partial treatment of TB can result in the dreaded complication of multiple drug resistance (MDR), a phenomenon that became widespread in several US cities during the 1980s and early 1990s.

Major efforts have been directed at controlling these public health problems with some success. Among the factors cited for improving the situation are better use of effective, short course treatment regimens, better institutional infection control measures, and perhaps, most importantly, the increased use of directly observed therapy (DOT). Even with these improvements, the problem of TB among the homeless remains significant. In a study of TB in homeless men in New York, 53% failed to complete therapy despite being in a DOT program. Burman et al5 reported in a Denver, CO, study that 18% of that city's DOT program patients were noncompliant with DOT and homelessness was a significant risk factor for noncompliance.

In the 1980s and early 1990s, problems with TB control among the homeless, similar to those described above, also occurred in San Diego County. The first major effort to deal with this problem was the implementation of essentially universal use of DOT among the homeless, which went into effect in 1992. However, based on subsequent experience and studies such as the ones cited above, it was recognized that DOT alone may not be sufficient to ensure completion of therapy among homeless individuals.