Link Between Diabetes and Tuberculosis: Risks, Outcomes, and Key Insights

Diabetes mellitus (DM) significantly increases the risk of developing active tuberculosis (TB), with affected individuals being 2–3 times more likely to contract the disease. Additionally, TB patients with DM face poorer treatment outcomes compared to those without DM, including lower cure rates and increased mortality. Dysglycemia, encompassing both DM and prediabetes, plays a critical role in shaping TB disease presentation. Among pulmonary TB (PTB) patients, dysglycemia prevalence at baseline was 61.4%, with 47.1% classified as prediabetes and 14.3% as DM. These patients frequently presented with more severe manifestations, including a higher prevalence of cavitary disease and extensive lung involvement on chest X-rays (CXR). See also: https://lintblab.weebly.com/profile.html

Patients with dysglycemia demonstrated significantly more advanced disease characteristics compared to their normoglycemic counterparts. For instance, cavitary disease was observed in 80.2% of dysglycemic patients versus 63.0% in normoglycemic TB (NGTB) patients, while bilateral lung lesions were more common (67.4% vs. 46.0%). Dysglycemic patients also had a greater median number of affected lung thirds (3 vs. 2). Sputum smear positivity rates were notably higher in the prediabetes and DM groups (93.0%) compared to NGTB patients (75.9%), further highlighting the aggressive disease course in dysglycemic individuals. However, resistant M. tuberculosis strains were more frequently detected in NGTB (20.9%) and prediabetes (19.0%) groups compared to DM (10.0%), suggesting differences in pathogen dynamics.

A South Korean study explored the broader implications of DM on TB through retrospective and cohort analyses. In newly diagnosed type 2 DM patients, the TB incidence rate was 3.7 per 1,000 individuals, with regional variations. In another study on multidrug-resistant TB (MDR-TB), 17% of patients also had DM. These patients faced worse outcomes, with treatment success rates significantly lower (36.0%) than those without DM (47.2%). DM was identified as an independent predictor of poor outcomes, alongside other factors such as low BMI and extensively drug-resistant TB (XDR-TB).

Further investigation into the Korean TB-POST cohort revealed a co-prevalence of DM in 26.8% of TB patients, with 12.5% developing new-onset diabetes (nDM) following TB diagnosis. Co-prevalence increased with age, particularly among men and those with lower incomes. New-onset diabetes patients were generally younger and exhibited more advanced TB at diagnosis, often with positive acid-fast bacilli (AFB) smears. These findings underscore the bidirectional relationship between TB and diabetes, with each condition exacerbating the severity and treatment challenges of the other.

Prediabetes, a precursor to DM, is also linked to unfavorable TB outcomes. A pooled analysis of eight cohort studies found that 25.1% of TB patients had prediabetes, which was associated with a higher incidence of treatment failure, recurrence, and other adverse outcomes. However, no significant increase in all-cause mortality was observed. These findings emphasize the urgent need for prospective studies to unravel the complex interplay between dysglycemia and TB, particularly in high-burden settings, and to guide tailored interventions for this high-risk population. See also: https://tbreadingnotes.blogspot.com/2024/10/glycemic-control-in-tuberculosis-tb0090.html

References:

1. Bezerra, A.L., Moreira, A.D.S.R., Isidoro-Gonçalves, L., Lara, C.F.D.S., Amorim, G., Silva, E.C., Kritski, A.L. and Carvalho, A.C.C., 2022. Clinical, laboratory, and radiographic aspects of patients with pulmonary tuberculosis and dysglycemia and tuberculosis treatment outcomes. Jornal Brasileiro de Pneumologia, 48(06), p.e20210505.
2. Yang, B.R., Kang, Y.A., Heo, E.Y., Koo, B.K., Choi, N.K., Hwang, S.S. and Lee, C.H., 2018. Regional differences in the incidence of tuberculosis among patients with newly diagnosed diabetes mellitus. The Clinical Respiratory Journal, 12(4), pp.1732-1738.
3. Kang, Y.A., Kim, S.Y., Jo, K.W., Kim, H.J., Park, S.K., Kim, T.H., Kim, E.K., Lee, K.M., Lee, S.S., Park, J.S. and Koh, W.J., 2014. Impact of diabetes on treatment outcomes and long-term survival in multidrug-resistant tuberculosis. Respiration, 86(6), pp.472-478.
4. Jeong D, et al. Prevalence and associated factors of diabetes mellitus among patients with tuberculosis in South Korea from 2011 to 2018: a nationwide cohort study. BMJ Open 2023;13:e069642.
5. Liang, L. and Su, Q., 2024. Prediabetes and the treatment outcome of tuberculosis: A meta‐analysis. Tropical Medicine & International Health, 29(9), pp.757-767.

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