High levels of drug-resistant TB in diabetes patients in Peru

Tuberculosis (TB) and type 2 diabetes mellitus (T2DM) are increasingly found together, and that combination creates a growing public health challenge. In places with a high burden of TB, like Peru, having both conditions has been linked to worse outcomes and a higher chance of drug-resistant TB. To shed light on this problem, a team led by corresponding author Marlon Yovera-Aldana examined medical records from a referral public hospital in Lima, Hospital María Auxiliadora. They carried out a cross-sectional study using secondary data from 130 adults who had both T2DM and microbiologically confirmed pulmonary TB and who were treated between 2015 and 2019. The study aimed to estimate how common resistance to first-line antituberculosis drugs is in this group and to look for factors tied to multidrug-resistant TB (MDR-TB). By focusing on people being treated at a single referral center, the researchers could describe the scale of drug resistance in a population already vulnerable because of diabetes, and provide evidence to inform how health services might detect and manage resistant TB among patients with long-standing chronic disease.

The researchers used existing laboratory and clinical records for 130 adults with microbiologically confirmed pulmonary TB and T2DM. Drug susceptibility test results were classified as sensitive, monoresistant, polyresistant, or MDR. To identify factors associated with resistance they used Poisson regression models with robust variance, an approach suited to estimating prevalence ratios in cross-sectional data. The study found that 34.6% of patients had resistance to at least one first-line drug, and 21.5% had MDR-TB. The most frequent single-drug resistances were to isoniazid (31%) and rifampicin (27%). In adjusted multivariable analysis, older age was linked to higher MDR-TB prevalence: patients aged ≥70 years had a prevalence ratio (PR) of 4.13 (95% CI: 1.16–14.7), and those aged 40–49 years had a PR of 2.99 (95% CI: 1.00–8.97). A T2DM duration of ≥5 years was also significantly associated with resistance to at least one drug, with an adjusted PR of approximately 2.1.

These findings point to a high burden of drug resistance among people who have both pulmonary TB and T2DM in this Peruvian referral hospital. The high percentages of resistance to isoniazid and rifampicin are especially concerning because resistance to those drugs drives multidrug resistance and complicates standard TB treatment. The associations with older age and longer diabetes duration suggest that vulnerability to drug-resistant TB may grow with age and with the chronicity of diabetes. For clinicians and health systems in high-TB-burden settings, this study supports closer attention to patients who have T2DM—particularly older adults and those who have had diabetes for many years—when TB is diagnosed. The authors conclude there is a need for integrated TB–diabetes management strategies to strengthen early detection and control of drug-resistant TB in this vulnerable population, an approach that could help tailor testing and treatment and potentially reduce poor outcomes linked to both conditions.