Epidemiology of tuberculosis in Sardinia: a comparison of two data-gathering methods.

SETTING: A complete surveillance system for tuberculosis should be able to guarantee constant updating of incidence and provide useful data on a variety of problems related to tuberculosis such as drug resistance, co-infection with the human immunodeficiency virus (HIV), the geographic origin of patients, and mycobacterial species. OBJECTIVE AND DESIGN: To assess the completeness of the surveillance system currently operating in Sardinia, cases seen by all medical centres between 1987 and 1995 were compared with those notified to Sardinian Public Health Services for the same period. RESULTS: Each year, on average 39% of cases seen in Sardinia are notified; 646 (40%) of the 1591 patients notified during the study period were never seen by regional medical centres. An analysis of the results shows that from 1992 the decline recorded in incidence rates in previous years ceased: 1992 (26/100,000), 1993 (25/100,000), 1994 (28/100,000), and 1995 (24/100,000). CONCLUSIONS: The current surveillance system in Sardinia is inadequate for performing an accurate epidemiological survey of the disease. Epidemiological analysis based solely on notification can provide neither reliable incidence rates nor useful information concerning many aspects of tuberculosis.