Relapses in multibacillary leprosy patients: effect of length of therapy

Two groups of MB leprosy patients, one treated to the point of smear negati vity (TSN) and the other given therapy for fixed duration (24 doses of WHO MB regimen) (FDT), were compared for relapse rates during treatment and in the posttreatment period. During the follow-up of 980.2 person yeats in 260 patients treated with FDT, 20 relapses (2.04/100 patient years) were obser ved. In the other group of 301 patients, who received therapy till smear ne gativity, 12 relapses in 1085.46 person yeats (1.10/100 patient years) occu rred. Comparison of survival rates (without relapse) has shown that althoug h there is no difference up to 4 years, the risk of relapse was significant ly higher on longer follow-up in the FDT group. In addition, when patients were compared on the basis of initial bacterial load, it was found that the relapse rates in patients with BI greater than or equal to 4 was significa ntly higher (P < 0.01) in the FDT group as compared to those receiving trea tment till the point of smear negativity (4.29 versus 1.27/100 patient year s). All the relapsed patients responded to retreatment with the same drug c ombination, indicating that the exacerbation in their condition was because of insufficient treatment, it is suggested that to prevent or reduce relap ses, treatment where feasible would be continued till smear negativity, at least in patients with high BI.