A Bayesian approach to understanding gender differences in tuberculosis disease burden

Abstract

Globally, men have a higher epidemiological burden of tuberculosis (incidence, prevalence, mortality) than women, possibly due to differences in disease incidence, treatment initiation, self-cure and/or untreated-tuberculosis mortality rates. Using a simple, gender-stratified compartmental model, we employed a Bayesian approach to explore which factors most likely explain men's higher burden. We applied the model to smear-positive pulmonary tuberculosis in Viet Nam (2006-07) and Malawi (2013-14). Posterior estimates were consistent with gender-specific prevalence and notifications in both countries. Results supported higher incidence in men and showed that both genders faced longer durations of untreated disease than estimated by self-reports. Prior untreated disease durations were revised upwards 8- to 24-fold, to 2.2 (95% credible interval: 1.7, 2.9) and 2.8 (1.8, 4.1) years for men in Viet Nam and Malawi, respectively, approximately a year longer than for women in each country. Results imply that substantial gender differences in tuberculosis burden are almost solely attributable to men's disadvantages in disease incidence and untreated disease duration. The latter, for which self-reports provide a poor proxy, implies inadequate coverage of case finding strategies. These results highlight an urgent need for better understanding of gender-specific barriers faced by men and support the systematic targeting of men for screening.