Objectives: To evaluate the relapse rate of tuberculosis after a complete course of antituberculous therapy in human immunodeficiency virus-infected patients and to identify the risk factors for relapse.
Patients and methods: Historic cohort study of all adult patients who were diagnosed as having human immunodeficiency virus infection and a first episode of culture-proved tuberculosis at 2 university hospitals in Madrid, Spain, between 1986 and 1992, and who completed at least 6 months of treatment were included and followed up until September 1994.
Results: Of 276 patients with human immunodeficiency virus infection and tuberculosis, 87 could not be evaluated (6 died before treatment, 39 died during treatment, 36 did not complete the planned therapy, and 6 were unavailable during treatment). The remaining 189 received a standard regimen (ie, 3 or 4 drugs, always including rifampin and isoniazid, for > or = 6 months). The median duration of follow-up for these 189 patients was 31.5 months, with a total of 4668 patient-months of follow-up after treatment; 105 patients (56%) were followed up until death. The relapse rate was 7.9% (2.7/100 patient-years). With multivariate analysis, a shorter duration of treatment and a low CD4+ cell count were associated with a greater probability of relapse. Relapses occurred in 5 (3.4%) of 148 patients who were treated for 9 or more months (1.7/100 patient-years) and in 10 (24%) of 41 patients who were treated for less than 9 months (10.9/100 patient-years) (P < .001; relative hazard, 9.2; 95% confidence interval, 3.1-26.9).
Conclusions: As standard antituberculous therapy for 9 months is associated with a low rate of relapse, maintenance therapy is not required. Duration of treatment for less than 9 months is associated with a high rate of relapse.