[How many cases of tuberculosis are not reported?].

Background: The aim of this study was to evaluate the degree of registry of tuberculosis and the factors associated to the same.

Methods: A retrospective study of the cases of respiratory tuberculosis diagnosed in the hospital A. Marcide-Novoa Santos (El Ferrol. La Coruña. Spain) from 1990 to 1992 was carried out. Identification was obtained from the registries of microbiology and pathology and the clinical history files. Registered cases were obtained from the nominal notifications to the Epidemiology Department of the local health service department. Sex, age, place of residence, previous history of tuberculosis, HIV, diagnostic method, localization of the tuberculosis, registration and reporting physician were evaluated for each patient.

Results: Three hundred ninety-three cases were identified of which 78 (19.8%) had been registered. Age and pulmonary localization were the variable influencing the degree of registration. Reporting was greater in the age group from 0 to 10 years (p < 0.05). Pulmonary tuberculosis was the most reported type although only 22.4% of the cases were declared. Bacilloscopy was positive in sputum in 190 patients and declared in 46 (24.2%). The degree of registration increased significantly over three years (p < 0.000001). Sex, previous history of tuberculosis, infection by the HIV and diagnostic method did not influence the degree of registration.

Conclusions: Seventy-five percent of the cases with positive bacilloscopy in sputum were not declared. The degree of declaration has improved over time, however, remains deficient being 2.7 fold lower than the total number of cases diagnosed in 1992.