Decreased survival of HTLV-I carriers in leprosy patients from the Democratic Republic of the Congo: a historical prospective study.

In this historical prospective study using sera stored for 22 years, we investigated the effect of HTLV-I infection on survival in a population of leprosy patients in the Democratic Republic of the Congo (formerly Zaire). We also determined the distribution of HTLV-I by subpopulation, age, and gender. Stored sera taken from a population of leprosy patients and controls in 1969 were tested for HTLV-I. Follow-up survival data on these patients were obtained in 1991. The sera collected in 1969 from 520 individuals was used to determine the prevalence of HTLV-I. Included in this number were 328 patients resident in the sanatorium. Survival and other data were available for 327 of these. A multivariate survival analysis using a logistic regression model was performed to evaluate the influence of HTLV-I status, age, type of leprosy, gender, duration of hospitalization, and ethnic group on survival. The overall prevalence of HTLV-I among the 520 individuals in the prevalence study was 34%, with 37.4% in the leprosy group and 25.2% in the control group (p < 0.01). Multivariate analysis using logistic regression showed that females of the Mongo and Ngombe ethnic group taken together were significantly more likely to be infected than the other groups (OR = 3.67, 95% CI: 2.14 to 6.30). A comparison of the death rates directly standardized for age and sex showed that the rate was significantly higher for HTLV-I positive (5.5/100 person-years of observation) compared with HTLV-I negative (3.6/100 person-years of observation). A survival analysis using the Cox model showed a risk ratio of 1.4 (CI: 1.04 to 1.89) for those infected with HTLV-I. An increase in the death rate was associated with HTLV-I infection in leprosy inpatients. The decreased survival associated with HTLV-I infection may result from an increased susceptibility to a variety of diseases.

PIP: Preservation of stored sera collected in 1969 from leprosy patients at a sanatorium in the Democratic Republic of the Congo's Equator Province enabled an analysis of the survival of carriers of human T-cell lymphotropic virus type 1 (HTLV-1). The HTLV-1 prevalence in the sera collected from 377 leprosy patients and 143 controls in 1969 was 34% (37.4% and 25.2%, respectively). Multivariate survival analysis was performed to evaluate the impact of HTLV-1 status, age, type of leprosy, gender, duration of hospitalization, and ethnic group on the survival of leprosy patients. Members of the Mongo ethnic group were more likely than those of the Ngombe ethnic group to be infected. After adjustment for age and sex, mortality was significantly higher among HTLV-1-positive cases (5.5 per 100 person-years of observation) than HTLV-1-negative persons (3.6 per 100 person-years of observation). A survival analysis using the Cox model revealed a mortality risk ratio of 1.4 (95% confidence interval, 1.04-1.89) for HTLV-1-positive individuals. The reduced survival observed in HTLV-1-infected leprosy patients presumably resulted from concomitant increased susceptibility to other diseases.

Selection of MDT strategies through epidemiometric modeling.

The epidemiometric model of leprosy, built on Polambakkam, India, data, is used to compare the impact on incidence of dapsone and different multidrug therapy (MDT) strategies. The simulations show that generalization of MDT could have a dramatic impact on transmission of the disease. Relapses after MDT, although important from an individual point of view, have a negligible influence on the incidence. Introduction of MDT requires investments that, during the first few years of the program, are much greater than for dapsone monotherapy. These are, however, rapidly absorbed due to the rapidly declining number of new cases, particularly when MDT is not limited to multibacillary cases but is administered to all patients.

Rate and time distribution of relapses in multibacillary leprosy.

Of the 47,068 patients registered in the Polambakkam Leprosy Center between 1955 and 1982, we selected 1886 cases having shown bacteriological positivity at any time during this period, whatever their classifications at registration, and subsequently found bacteriologically negative. After an average follow-up period of 10 years, 243 relapses were observed, giving a crude relapse rate of 12.8 per person-years of observation and a cumulative probability of relapse of 18.9%. Relapse rates were found to be dependent on regularity during smear-positive and -negative periods; a regularity greater than 75% in the smear-positive period proved to be particularly important. The results show no evidence that relapses occurring after 3 years of negativity could be reinfections, and that the relapse rate was still affected by regularity 7 years after negativation. The median delay of relapses was found to be 4.4 years and was not affected by the regularity of treatment.

Registration of the number of macules in paucibacillary leprosy for evaluation of early diagnosis and individual prognosis.

The number of macules is usually registered at diagnosis in the first clinical examination of leprosy patients. The question studied here is whether this practice is of any interest as an indicator of the precocity of detection of the prognosis. The study is based on the 26,996 paucibacillary patients detected from 1957 to 1982 in Polambakkam Leprosy Centre (South India) for whom the number of macules and disability status are assessed and registered. Several observations suggest that the proportion of single-macule patients among the newly detected cases is a more sensitive indicator than the proportion of new patients with disabilities for the evaluation of the delay between onset of the disease and detection. Its use could be especially helpful for programmes running for several years, when it becomes difficult to observe significant variations in the proportion of patients with disabilities. Regarding the prognosis value of the number of macules, inactivation and relapse probabilities were calculated. Regularity of treatment is found to be a better predictor of early inactivation than the number of macules, while relapse probabilities are more affected by the number of macules.