[Tuberculosis in a prison population: a study of 138 cases]

Tuberculosis continues to be a disease of great importance in Spain with few data known on prison populations. In the present study an analysis of the incidence and characteristics of tuberculosis in the prison population people is done.

The General Penitentiary Hospital attends a prison population from the penitentiary centers of Madrid and its surrounding areas. From 1 March 1991-31 August 1992 a retrospective study of the patients with tuberculosis diagnosed by culture isolation of Mycobacterium tuberculosis was performed. Demographic, clinical, analytical, microbiologic analysis as well as data concerning to associated infections, antituberculous treatment and its possible toxicity as well as the evolution of the patients were collected.

During the period studied 138 patients--120 corresponding to the area of Madrid and 18 to patients referred from other penitentiary areas--were diagnosed. The rate of incidence of tuberculosis in the penitentiary population in the area of Madrid was of 1170.5 cases per 100,000 prisoners per year (confidence interval [CI] 95%; 961-1380). The mean age was 30 years (CI 95%; 29-31) and 97% were males. Eighty-four percent were positive for the human immunodeficiency virus (HIV) and 84% were intravenous drug addicts. The clinical form of presentation of the tuberculosis in the HIV positive patients was: pulmonary in 57% of the cases, disseminated in 29% and extrapulmonary in 14% and was pulmonary in all the cases of HIV negative patients. The mean CD4 lymphocytes count was 0.216 x 10(9)/l in HIV positive patients with pulmonary tuberculosis, and in disseminated tuberculosis was 0.062 x 10(9)/l (p < 0.001). The positivity of acid-alcohol resistant staining in the sputum samples and/or induced sputum was 67.4% in the patients with pulmonary tuberculosis and 77.4% in disseminated tuberculosis. Ten percent of the patients were found to abandon antituberculous treatment in the first trimester.

The incidence of tuberculosis in the prison population in much higher than that for the general population in Spain, largely due to the high prevalence of HIV infection in this population.