Recurrent tuberculosis in Denmark: relapse vs. re-infection

TY - JOUR

T1 - Recurrent tuberculosis in Denmark: relapse vs. re-infection

AU - Bang, D

AU - Andersen, Åse Bengård

AU - Thomsen, Ole

AU - Lillebaek, T

PY - 2010/4/1

Y1 - 2010/4/1

N2 - SETTING: Denmark, a country with a low-incidence of tuberculosis (TB). OBJECTIVE: To analyse the proportion of relapse vs. reinfection and to compare selected characteristics between the two subgroups. DESIGN: A population-based cohort study. All 4154 Mycobacterium tuberculosis isolates from patients in Denmark genotyped by insertion sequence 6110 restriction fragment length polymorphism were followed for recurrent TB over 13.5 years. Recurrent cases were classified as relapse or re-infection by genotype patterns in initial and serial disease episodes. RESULTS: Recurrent TB was found in 73 (1.8%) cases. Identical M. tuberculosis genotypes in initial and serial episodes were found in 54 (1.3%), indicating relapse, whereas different genotypes, representing re-infection, were found in 19 (0.5%) cases. Cavitary TB in the initial episode was significantly associated with relapse (OR 4.6, 95%CI 1.1-26.9) compared to re-infection. CONCLUSION: The rate of recurrent TB is low in Denmark. Comparing selected characteristics between the relapse and re-infection subgroups revealed that only the presence of cavitary disease was associated with relapse. Although recurrent TB was rarely due to re-infection, the risk of re-infection increased with time.

AB - SETTING: Denmark, a country with a low-incidence of tuberculosis (TB). OBJECTIVE: To analyse the proportion of relapse vs. reinfection and to compare selected characteristics between the two subgroups. DESIGN: A population-based cohort study. All 4154 Mycobacterium tuberculosis isolates from patients in Denmark genotyped by insertion sequence 6110 restriction fragment length polymorphism were followed for recurrent TB over 13.5 years. Recurrent cases were classified as relapse or re-infection by genotype patterns in initial and serial disease episodes. RESULTS: Recurrent TB was found in 73 (1.8%) cases. Identical M. tuberculosis genotypes in initial and serial episodes were found in 54 (1.3%), indicating relapse, whereas different genotypes, representing re-infection, were found in 19 (0.5%) cases. Cavitary TB in the initial episode was significantly associated with relapse (OR 4.6, 95%CI 1.1-26.9) compared to re-infection. CONCLUSION: The rate of recurrent TB is low in Denmark. Comparing selected characteristics between the relapse and re-infection subgroups revealed that only the presence of cavitary disease was associated with relapse. Although recurrent TB was rarely due to re-infection, the risk of re-infection increased with time.

M3 - Journal article

SN - 1027-3719

VL - 14

SP - 447

EP - 453

JO - International Journal of Tuberculosis and Lung Disease

JF - International Journal of Tuberculosis and Lung Disease

IS - 4

ER -