The extrapulmonary dissemination of tuberculosis: A meta-analysis

Background and objective: The epidemiology of the forty percent of tuberculosis patients who present with disseminated and/or extrapulmonary disease is in need of further study. Further study of such dissemination using published data from international indices may provide data which assist with control of tuberculosis. Methods: For each clinical or epidemiologic factor studied, summary odds ratios and corresponding 95% confidence intervals were calculated showing associations between such factors and documented extrapulmonary dissemination of tuberculosis. Results: Eighteen studies fulfilled criteria for study of the clinical factors and nine for the cytokine studies. Significant factors associated with a greater risk of extrapulmonary dissemination were female gender (summary odds ratio, 1.92 (95% confidence intervals, 1.72–2.13), I-squared 86.9), age under 45 (1.37, 1.18–1.60, 63.7), and as well the absence of smoking, drinking and diabetes but not HIV infection (1.10, 0.91–1.32, 80.5). Among cytokines, the macrophage receptor protein P2X7 was associated most strongly associated with extrapulmonary dissemination of tuberculosis (2.28, 0.88–5.90, 92.9). Conclusion: Young age, female gender, and the macrophage purinergic receptor protein P2X7 were major factors associated with extrapulmonary dissemination of tuberculosis.