[The epidemiology of the acquired immunodeficiency syndrome in Barcelona (1981-1991) (I). A descriptive study and time trends].

BACKGROUND

To analyze the epidemiologic situation of AIDS in Barcelona with a descriptive study and a temporal trends analysis.

METHODS

Patients detected between 1981 and 1991 were included through a system of active surveillance. Relative risks (RR), odds ratios (OR) with 95% confidence intervals and Student's t-test were calculated. The monthly time distribution of cases was analyzed by different adjustments.

RESULTS

2,321 cases were detected, 70.8% of whom were Barcelona residents. The cumulative incidence rate was 94.7/100,000, and the annual rate for 1991 was 23.4/100,000. The active surveillance system detected 35.0% of cases in 1991. Males showed a higher rate than females (RR = 5.9; CI: 5.2-6.6). Cumulative rates varied between 63.1/100,000 and 263.8/100,000 according to district of residence. 50.9% were intravenous drug users (IVDU) and 33.2% homosexuals, with 15% of the women being attributed to heterosexual transmission. Cases among IVDU were younger than among homosexual cases (p < 0.001). The predominant indicator diseases were Pneumocystis carinii pneumonia (20.6%) and extrapulmonary tuberculosis (19.4%). 41.2% of the cases had a previous history of tuberculosis, a disease more common among IVDU than homosexuals (OR = 4.3; CI: 3.4-5.6). The same occurred among those with a prison record (OR = 46.6; CI: 23.8-103.8). With regard to temporal trends, IVDU showed a greater tendency to increase than homosexuals, but heterosexuals showed a greater percentage increase than both.

CONCLUSIONS

Active epidemiologic surveillance allowed more exhaustive and precise knowledge of AIDS epidemiology. Important differences were seen in incidence and in risk groups according to city districts. The heterosexual route is that which has undergone the greatest increase in the last few months.