Tuberculosis as a re-emerging disease and the risk in diabetics on the Texas Mexico border

Bassent Abdelbary, The University of Texas School of Public Health


Tuberculosis (TB) is the second cause of death worldwide due to a single infectious agent. The Texas- Mexico border has higher TB incidence rates (12/100,000 in the south Texas border with Mexico, and 30/100,000 in Tamaulipas in 2014) than the corresponding national averages of 2.96/100,000 for the US and 21/100,000 for Mexico. Chronic diseases such as diabetes mellitus (DM) compromise immunity and increase the risk of acquiring TB. DM is also associated with adverse TB treatment outcomes in those who have both diseases. As a follow-up of a previous study in 1998-2004, we reassessed the prevalence of DM and its associated factors among 8,431 TB patients using surveillance data from 2006-2013 for the Mexican state of Tamaulipas, across the border with Texas. Prevalence of DM was 25.2%, with an increase of at least 2.8% over the study period. Newly discovered factors associated with TB-DM (versus no DM) were lower education and higher unemployment (p< 0.001), which are reportedly associated with poorer DM management. TB-DM patients were more likely to have smear-positive, pulmonary (versus extra-pulmonary) and drug-resistant TB (1.9-, 3.8- and 1.4-fold, respectively). During treatment, TB-DM patients were more likely to be smear-positive, and less likely to die or abandon TB treatment. Additionally, we assessed demographic and other clinical differences by adverse outcome status (treatment failure or death). Drug resistance was also assessed to detect those with a higher risk profile. We developed a risk score based on predictive modeling to assess the demographics and clinical presentation that distinguished those who later presented with adverse events.^ Final predictive models revealed that TB patients who failed their treatment regimen with first-line antibiotics were more likely to have at most a primary school education, MDR-TB, and few to moderate bacilli on AFB smear. TB patients who died during treatment were more likely to be older males with MDR-TB, HIV, malnutrition, and reporting excessive alcohol use. TB patients showing resistance to any of the five tested drugs were more likely to be younger presenting with pulmonary TB and have an initial positive AFB smear. Modified risk scores were developed with strong predictability for treatment failure and death, and moderate predictability for drug resistance. A separate set of risk scores that was developed for TB-DM patients showed moderate predictability for death. The available variables were not robust predictors of drug resistance, indicating the need for prompt testing or further characterization of TB patients at the time of diagnosis.^

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Recommended Citation

Abdelbary, Bassent, "Tuberculosis as a re-emerging disease and the risk in diabetics on the Texas Mexico border" (2016). Texas Medical Center Dissertations (via ProQuest). AAI10247075.