Risk of having pulmonary tuberculosis in type 2 diabetes: A hospital-based matched case-control study

Diabetes mellitus (DM) leads to nearly 3-fold higher risk of pulmonary tuberculosis (TB), indicating an increasing challenge to public health in low-to-middle income countries. Till now, the risk factor is still uncertain. We carried out this study with the main purpose to identify the risk factors of having TB in DM patients.

A hospital-based matched case-control study was conducted in Qingdao, China from March, 2016 to January, 2018. Cases were DM patients with concurrent TB (DM-TB). Each case was matched with two controls, patients with DM only of similar age, sex and DM course. Cox regression of conditional logistic analysis was used to define the risk factors for having TB in DM, and then sensitivity analysis was carried out.

We identified 315 patients, including 105 cases and 210 controls. Smokers had a higher risk of having TB with a multivariable adjusted odds ratio (aOR) of 12.45 than non-smokers. Poor glycemic control (aOR=2.66), frequency of DM re-examination <1 time/year (aOR=3.39), as well as TB contact history was also independently related with higher risk, while BMI ≥24 (aOR=0.42), education level ≥ college (aOR=0.11) showed a negative association.

Poor glycemic control, smoking, low frequency of reexamination was associated with higher risk of having TB in DM, while overweight and obesity, high education levels showed a negative association. These findings provide clues to target DM populations prone to TB, which may be of help to halt the epidemic of TB in high burden countries.