Tuberculosis in an inflammatory bowel disease cohort from South Africa

BACKGROUND: Potent immunosuppressive therapy is standard treatment for inflammatory bowel disease (IBD) but carries a risk of reactivating latent tuberculosis (TB). No data exist on the burden of TB in South African patients with IBD. OBJECTIVE: To evaluate the burden of TB in IBD patients attending a large tertiary IBD clinic. METHODS: Data pertaining to patients attending the Groote Schuur Hospital IBD clinic were retrospectively analysed. Data were extracted from an existing IBD database, patient notes, the National Health Laboratory Services database and chest X-ray analysis. RESULTS: Of 614 patients, 72 (11.7%) were diagnosed with TB; 40 (55.6%) developed TB prior to the diagnosis of IBD. On regression analysis, coloured IBD patients were at increased risk for TB development (p=0.004, odds ratio (OR) 3.57, 95% confidence interval (CI) 1.49 - 8.56), as were patients with extensive Crohn's disease (CD) compared with those with less extensive disease (p=0.001, OR 2.84, 95% CI 1.27 - 6.33). No other risk factors, including the use of immunosuppressive agents, were identified for the development of TB. CONCLUSIONS: Of over 600 patients, 12% had TB either before or after IBD diagnosis. The high rate of previous TB and positive association with ethnicity probably reflect the high burden of TB in a socio-economically disadvantaged community. We recommend that IBD patients should be screened actively and monitored for TB when immunosuppressive medications are used.