Study objectives: To characterize the incidence of extrapulmonary tuberculosis (EPTB) in Estonia, by site and age, in conditions of marked pulmonary tuberculosis (TB) increase, ie, during the period of fundamental societal changes, but where TB incidence has not been influenced by HIV infection.
Design and setting: A retrospective study.
Patients: All new cases of EPTB (n = 622) detected in Estonia from 1991 to 2000.
Results: The incidence of pulmonary TB in Estonia increased from 21.5 in 1991 to 44.6/100,000 in 2000. In contrast, the incidence of EPTB did not increase at the same pace, changing only from 3.6 in 1991 to 4.7/100,000 in 2000. The increase in the incidence of EPTB was significantly lower than that of pulmonary TB (p < 0.05), and the relative frequency of EPTB among overall TB steadily decreased from 17.0% in 1991 to 10.1% in 2000. The incidence of EPTB forms with a long latency period (eg, osteoarticular and urogenital TB) remained unchanged, while that of EPTB forms with a short latency period (eg, intrathoracic lymph node TB) increased (p < 0.05). The number of cases of urogenital, pleural, and osteoarticular TB increased with age; the number of cases of intrathoracic lymph node TB decreased with age. The bacteriologic confirmation rate was lower in EPTB than in pulmonary TB and varied according to site.
Conclusion: There was no increase in the incidence of EPTB during 10 years despite the dramatic increase in overall TB. The proportion of EPTB among all TB tended to decrease with increasing age, and different EPTB sites prevailed in different age groups.