Relapses in multibacillary leprosy patients: A retrospective cohort of 11 years in Colombia

OBJECTIVES: To determine the frequency and factors associated with relapse in multibacillary leprosy. DESIGN: We performed a retrospective cohort study on multibacillary leprosy patients treated at Centro Dermatologico Federico Lleras Acosta between January 1994 and December 2004. By survival analysis we studied the incidence density for recurrence and bacillary index conversion. The assessment of risk factors associated with the occurrence of relapse was constructed using a Cox regression model. RESULTS: We included 299 cases of which 243 received WHO-MB MDT on a regular basis, and followed them up to assess the frequency of relapses. We obtained 490 person-years of follow-up and an incidence density of 6.70 relapses/100 patient-years that was higher than most of the data reported in the literature. The relapse rate was 9.80 per 100 person-years when the initial bacillary index was > or = 2.0 and 5.60 relapses/100 patient-years when it was or = 2.0, antireactional treatment and clinical classification of lepromatous leprosy. For each variable, the risk was four to five times more likely to present relapse. We also found that 21 patients' BI became negative per 100 treated for 1 year with WHO-MB MDT. CONCLUSIONS: We found a high relapse rate associated with initial high bacillary index in the Colombian population. Among the patients who received MDT on a regular basis 33 out of 165 (20%) relapsed.