Abstract

FREIRE, Denison Noronha; BONAMETTI, Ana Maria  and  MATSUO, Tiemi. Early diagnosis and progression of tuberculosis in contacts. Epidemiol. Serv. Saúde [online]. 2007, vol.16, n.3, pp.155-163. ISSN 1679-4974.  http://dx.doi.org/10.5123/S1679-49742007000300002.

The objective of this work is to evaluate the profitability of chest X-rays as a resource of premature diagnosis of tuberculosis and the risk of secondary cases among contacts of index-cases. A retrospective study was performed at 3,091 contacts of 879 tuberculosis index-cases admitted for treatment in the Sanitary Pulmonary Ambulatory in the Municipality of Londrina, State of Paraná, Brazil. The association between the initial X-ray abnormality and the subsequent occurrence of the disease in contacts was evaluated by the relative risk, and confirmed in 13.7% (10/73). The chest X-ray results, realized in contacts in the admission of the index-cases, were classified as a premature diagnosis for tuberculosis, and 4.3% of contacts (73/1,698) were classified as suspect cases. The progress of the disease in contacts was estimated by Kaplan-Meyer's curve, and its frequency by cumulative incidence and incidence density. The risk of getting ill in the contacts with suspected X-ray results was 6.13 times bigger than the risk in contacts with normal X-ray results. The probability of acquiring the disease in contacts, in five years, was approximately 2%. In conclusion, the chest X-ray exam is important when screening contacts. However, its profitability was considered low in the early diagnosis, and the risk of the disease, during a period of five years, still persists.

Keywords : tuberculosis; contacts and progression to disease; chest X-ray.

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