Relapses in multibacillary leprosy
To the Editor:
I wish to offer the following comments on the paper entitled " Rate and Time Distribution of Relapses in Multibacillary Leprosy," by Kurz, et al. published in the International Journal of Leprosy 57 (3) 1989, 599-606.
In the life table analysis used in the analysis of the data, it is assumed that the probability of undergoing an event is constant. Factors such as initial bacterial load, age, and immunological status of the patient would have certainly influenced the occurrence of the event, in addition to the treatment and its regularity. Because of the rigid selection criteria, large numbers of patients were excluded from the study. It would be interesting to know whether the group excluded had any particular attributes and the extent to which their exclusion has influenced the figures of relapse rates.
Regarding the statement of the authors in the summary, " The results show no evidence that relapses occurring after 3 years of negativity could be reinfections...." I failed to find any evidence from the data published in the paper that supports this statement except probably the continuation of treatment after negativity. Nowhere is it mentioned as to whether all the patients who have relapsed were on dapsone (DDS) until the occurrence of the relapse. Certainly there must be some cases where the treatment was stopped. Add to this the possibility of 20% of the cases (as per the authors' own experience) not consuming the drugs. Then so-called relapses from these two groups could as well be reinfections. In addition, from among the patients on monotherapy the reinfection could have occurred by the DDS-resistant organisms, although this is a rare possibility.
I shall be much obliged if the authors can kindly offer their comments.
- Dr. R. N. Reddy
Assistant Director (Epidemiology)
Central Leprosy Teaching & Research Institute
Chengalpattu 603001
Tamil Nadu, India