[Extrapulmonary tuberculosis in Poland in the years 1974-2010]

The incidence of tuberculosis in Poland decreased from 128.5 in 100 000 in 1970 to 19.1 in 100 000 in 2010. In many countries, but not in Poland, according to the improvement of the epidemiological situation of tuberculosis (TB), the proportion of the extrapulmonary form of this disease is increasing. The aim of this study was to describe changes in extrapulmonary TB epidemiology in Poland from 1974 to 2010.

Retrospective analysis of data from National TB Register on tuberculosis in Poland in the years 1974-2010. The percentage of extrapulmonary tuberculosis among all cases of tuberculosis, the differences in the proportion of extrapulmonary tuberculosis, and differences in various locations of lesions in this form of disease in relation to sex and age groups were assessed. Information was collected from about 626,093 cases of tuberculosis reported to the Register during the period 1972-2010. In 62,251 cases extrapulmonary tuberculosis was the only form of the disease (9.9% of all tuberculosis cases). The study material consisted of 396,344 male and 196,184 female cases; 30,885 subjects were 0-19 years of age, 191,542 were 20-39 years old, 237,256 were 40-59 years old, and 166,410 subjects were ≥ 60 years old. We compared data from the years 1974-1982 with more recent data (2002-2010). The test of proportions for two independent samples was used to assess the significance of differences in proportions.

The proportion of extrapulmonary tuberculosis (EPTB) among all TB cases was 11.2% in the years 1974-1982 and only 8.2% in the years 2002-2010. This difference was significant. The proportion of EPTB among all TB cases was higher in women than in men and was higher in people aged 0-19 years than in other age groups. The location of extrapulmonary tuberculosis was different in women and in men. Pleural TB was the most common form of extrapulmonary tuberculosis in both sexes with a predominance of males. Peripheral lymph nodes, bones and joints, urinary, genital, and skin TB were more common in women (these differences were significant). In the youngest age group intrathoracic lymph node TB dominated, and in the older age groups it was pleural TB. In accordance with the increase in age, the proportion of urinary tract, peripheral node, and pericardium TB increased. Central nervous system TB showed no predilection for a particular age group.

The proportion of EPTB to all cases of TB is lower in Poland than in other countries. In addition, the proportion of EPTB had significantly decreased from 1974-1982 to 2002-2010. It may be due to difficulties in diagnosis of those forms of TB in Poland. Alternatively it is possible that those cases diagnosed in non-respiratory centres are not reported to the National TB Register.