[Tuberculosis notification from 1987 to 1999 for the public health area of the community of Valencia (Spain)]

Abstract

Objective: Under notification of tuberculosis (TB) is common worldwide but has hardly been studied in Spain. The objective of this study was to determine how many cases of TB are reported in our health care area.

Material and method: Between 1987 and 1999 we carried out a direct study of the incidence and reporting of TB cases in our area (106,632 inhabitants on the census). Cases were taken from mandatory notification, pathology and bacteriology files and were then reviewed.

Results: Of the 410 TB cases diagnosed, 378 were residents of the area (annual incidence: 27/100,000 inhabitants), 223 of whom were reported (54%). Forty-eight patients were under 15 years of age. Sixty-seven percent of the pediatric cases and 53% of the adult cases were reported (n.s.). Of the 78 cases with HIV co-infection, only 32% were reported, in contrast with 60% of HIV-negative cases (p < 0.001). Of the 300 cases with pulmonary involvement, 56% were reported, versus 50% of those with exclusively extrapulmonary involvement (n.s.). For the 149 with positive Ziehl-Neelsen stain, 61% were reported, in contrast with 51% of those who were smear negative (n.s.). Diagnosis was based on clinical signs in 65 cases (16%), 51% of which were reported, versus 55% of those in which diagnosis was based on bacteriology or histology consistent with TB (n.s.). Overall under notification tended to decrease during the study period (r = 0.73, p < 0.005). Under notification also tended to decrease for patients with pulmonary involvement (r = 0.83, p < 0.0001) and for those with positive Ziehl-Neelsen staining of sputum (r = 0.79, p< 0.001). Likewise, under notification also decreased for HIV negative patients (r = 0.74, p < 0.02) but not significantly so for HIV positive patients r = 0.44, n.s.).

Conclusions: Direct quantification of cases revealed a significant degree of under notification that is tending to decrease. Under notification is greatest for HIV-positive patients and is not changing. No differences were seen for smear positive and smear negative patients, by pulmonary or extra-pulmonary involvement, for clinical versus laboratory diagnosis, or for patients who were younger or older than 15 years of age. Reporting should be improved so that measures to decrease the incidence of TB can be taken.