Relapse of tuberculosis after treatment in human immunodeficiency virus-infected patients

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.

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.

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).

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.