A study of relapse after MDT in a district in West Bengal, India.

A study was undertaken to estimate the magnitude of the problem of relapse and to identify factors responsible for relapse in leprosy units that were delivering MDT in Purulia District of West Bengal. From records patients were classified as "Relapse" or "Not relapse". "Not relapse" patients were selected by simple random sampling from the Surveillance Register and were matched according to age, sex, and the leprosy control unit. 128 cases ("Relapse") and 128 controls ("Not relapse") were interviewed in the clinic using a pre-tested questionnaire. Details of methods to identify and confirm relapse were circulated to all reporting units for ensuring uniformity and reliability. NGOs covered 42% of the population, while the State Government covered the remaining. The patients had been followed up after completion of treatment for a period of two years in PB leprosy and for five years in MB leprosy. The study revealed that the relapse rate was 1.71/1000 person-years for original PB cases and 0.76/1000 person-years for original MB cases. The study also showed that history of contact with an active leprosy patient and irregular treatment led more PB cases to relapse than control cases. All patients with an initial BI of 3+ relapsed with a BI of 1+ or 2+.