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.