Tuberculosis prophylaxis in the homeless. A trial to improve adherence to referral

Adherence to tuberculosis evaluation is poor in a high-risk population such as the homeless.

To test two interventions aimed at improving adherence to tuberculosis evaluation and to identify predictors of adherence.

We conducted a randomized clinical trial in shelters and food lines in the inner city of San Francisco, Calif. We randomized 244 eligible subjects infected with tuberculosis to (1) peer health adviser (assistance by a peer [n = 83]), (2) monetary incentive ($5 payment [n = 82]), or (3) usual care (referral slips and bus tokens only [n = 79]). The primary outcome of the study was adherence to a first follow-up appointment at the tuberculosis clinic, where subjects were evaluated for active tuberculosis and the need for isoniazid prophylaxis.

Of the subjects assigned to a monetary incentive, 69 (84%) completed their first follow-up appointment, compared with 62 subjects (75%) assigned to a peer health adviser and 42 subjects (53%) assigned to usual care. Adherence was higher in the monetary incentive and peer health adviser groups than in the usual care group (P < .001 and P = .004, respectively). Patients not using intravenous drugs and patients 50 years of age or older were more likely to adhere to a first follow-up appointment (odds ratios [95% confidence intervals], 2.5 [1.3 to 5.0] and 3.3 [1.2 to 8.8], respectively). Among the 173 tuberculosis-infected subjects who completed their appointment, isoniazid therapy was started for 72 individuals, and three cases of active tuberculosis were identified.

A monetary incentive or a peer health adviser is effective in improving adherence to a first follow-up appointment in homeless individuals infected with tuberculosis. A monetary incentive appears to be superior. Intravenous drug users and young individuals are at high risk for poor adherence to referral.