Vigilância das meningites na Região Metropolitana de Belo Horizonte, MG, 1999: o uso dos sistemas de informação em saúde e o método da captura-recaptura na estimação da incidência e da subnotificação

Abstract

The purpose of this study was to evaluate surveillance for meningitis in the Metropolitan Area of Belo Horizonte, Minas Gerais, Brazil, in 1999, on the basis of cases registered in three data sources systems: the mandatory notifiable disease surveillance system SINAN; the hospital registers SIH-SUS and the national mortality registry SIM. Epidemiological profile of the cases was described, and some aspects of the quality of the available information were assessed. The incidence and the completeness of the surveillance system were estimated usingcapture-recapture methodology. A total of 1,320 were reported at least to one source, comprising 918 distinct cases, with 1.9% of common cases recorded simultaneously to all sources. In SINAN, out of 587 confirmed meningitis, 254 were bacterial meningitis [97 (16.6%) caused by N. meningitidis, 37 (6.3%) by S. pneumoniae and 24 (4.1%) by H. Influenzae], 87 probable bacterial, 209 probable viral and 59 had no specification of the etiology. The completeness of items on surveillance forms in SINAN ranged from 100% (data of identification and address) to less than 10% (exposure to an index case, chemoprophylaxis, previous vaccination, blood laboratories data). After merging cases by patientsname, date of birth and address, probabilistic models of capture -recapture were used to estimate the total number of meningitis cases. The Lincoln-Petersen model (two sources: SINAN and SIH-SUS) yielded 1,187 cases (95% CI: 1,033- 1,166) and Mt model 1,085 cases (95% CI: 1,046-1,137) and 1,100 cases (95% CI: 1,061- 1,150) using the three sources. The sensitivity of SINAN and SIH-SUS were 66% and 51%, respectively, using two sources estimation and 65% and 50% with three sources. The incidence of reported meningitis was 17,7/100,000(14,5/100,000 for confirmed cases), the estimated rate reached 27.2/100,000. In spite of being incomplete in some clinical, diagnostic, laboratorial and epidemiological aspects, the information of SINAN provided a consistent profile of meningitis according to literature; the hospital registers could be useful for surveillance system but requires adjustments in the information provided by the data sets. An integrated surveillance would improve the sensitivity of a standard system; the capture-recapture methodology represents an alternative of reference of the total real cases to be found. One third of patients and their closecontacts were not detected by surveillance system and might got neitherprevention nor treatment, essential to reduce sequelae and case fatality rates.