A study on the effectiveness and safety of the WHO/MDT regimen in the Northeast of Thailand; a prospective study, 1984-1996

The aim of this prospective study was to determine the effectiveness and safety of the multidrug therapy as recommended by the World Health Organization (WHO/MDT) in 1982. One-hundred-eighty-eight newly diagnosed leprosy patients [130 paucibacillary (PB) and 58 multibacillary (MB) patients] from three provinces in northeastern Thailand were recruited into a study from April 1984 to March 1985. The study lasted until May 1996. The results showed that 182 patients finished their course of WHO/MDT, representing a treatment completion rate of 95%; 167 (122 PB and 45 MB) were released from surveillance (RFS); 82 PB patients were still available for follow up by the end of 1994 and 31 MB patients by May 1996. Two PB patients were diagnosed with a relapse, showing a relapse rate of 0.2 per 100 person-years at risk. After an average of 8 years of follow up, no MB relapses have been diagnosed. The proportion of patients with a WHO grade 2 disability among PB and MB patients increased from 4% and 8% at the start of treatment to 7% and 13% at last examination, respectively. It is concluded that the fixed-duration, 6-month WHO/MDT regimen for PB leprosy and the 24-month regimen for MB leprosy are effective, acceptable and safe, and that clinical activity, histopathological activity and/or a positive skin smear at release from treatment (RFT) have no bearing on the efficacy of the WHO/MDT regimens. The relapse rates are low and in accordance with most published data available to date. The importance of skin-smear services for a reliable classification (WHO PB/MB classification for control programs) is stressed.