Epidemiology of Mycobacterium tuberculosis infecion in Pavia province, Lombarady, Northern Italy, 1998-2013

This study investigated the epidemiology of tuberculosis in the last 16 years in the province of Pavia, Lombardy, Northern Italy. The objective was to evaluate the clinical pattern of tuberculosis in immigrant groups compared with Italians in an observational retrospective study conducted from 1998 to 2013. In all, 615 tuberculosis cases were admitted, 354 males (57.3%), median age 47-years, 425 (69.1%) Italian-born patients, 190 (30.9%) immigrants. The ratio between the immigrant group and the Italian-born group of patients increased from 1.7% to 54.5% in the study period (p=0.001). HIV was the most common comorbidity, affecting 48 patients (7.8%), followed by diabetes in 35 (5.7%) and COPD in 30 (4.9%). The overall admission-associated mortality was 5.5%. Italian-born patients were older than non-Italian born subjects and had at least one comorbidity, 162 (38.1%) and 22 (11.6%), respectively (p<0,0001). Mortality was increased among Italian-born compared with non-Italian-born patients (7.3% versus 1.6%, p=0.004). No significant variation in extra-pulmonary tuberculosis (EPTB) prevalence occurred. Considering specific form of EPTB, HIV infection was associated with an increased risk of EPTB (RR 2.02, 95%CI 1.09-3.74, p=0.026). There was a high risk of tuberculosis among immigrants, whereas a decreasing trend was consistently observed among Italian-born patients. Italian-born patients show a higher tuberculosis-associated mortality risk due to older age and comorbidities.