Diabetes and risk of tuberculosis relapse

Lee, P.H., Lin, H.C., Huang, A.S.E., Wei, S.H., Lai, M.S. and Lin, H.H., 2014. Diabetes and risk of tuberculosis relapse: nationwide nested case-control study. PloS one, 9(3), p.e92623.

Presence of diabetes mellitus (DM) during anti-TB treatment was linked to a higher risk of TB relapse.

The association between DM and TB relapse decreased in individuals older than 60 years.

DM was independently related to an increased risk of TB relapse in the national cohort of TB patients.

Strengthen follow-up strategies for DM-TB patients after anti-TB treatment to detect relapse early.

TB programs should focus on rigorous glucose control for DM-TB patients.

Williams, V., Onwuchekwa, C., Vos, A.G., Grobbee, D.E., Otwombe, K. and Klipstein-Grobusch, K., 2022. Tuberculosis treatment and resulting abnormal blood glucose: a scoping review of studies from 1981-2021. Global Health Action, 15(1), p.2114146.

Diabetes as a Risk Factor for Tuberculosis (TB):

• Numerous studies suggest that diabetes (DM) is a risk factor for TB.
• It remains unclear whether TB or its treatment increases the risk of developing diabetes.
• Impaired glucose tolerance (IGT) may occur during treatment with anti-TB drugs and might resolve after treatment.
• This IGT could result from:
  • Undiagnosed diabetes.
  • A stress response to infection, which increases levels of stress hormones (interleukin-1, interleukin-6, TNF-alpha).
  • Abnormal pancreatic function or TB-induced pancreatitis affecting endocrine function.

Blood Glucose Testing During TB Treatment:

• The Fasting Blood Glucose (FBG) test was the most common method for estimating blood sugar, followed by the Oral Glucose Tolerance Test (OGTT) and HbA1c.
• There was no standardized approach for blood sugar testing; most studies used a combination of methods.
• In studies using multiple tests:
  • HbA1c values were higher.
  • Patients with baseline values in the DM or IGT range were more likely to maintain hyperglycemia throughout treatment.
• HbA1c is useful for identifying long-term glucose abnormalities.
• To better identify DM comorbidity during TB treatment, blood glucose screening timing should be standardized across patients and country programs.
• Some studies only repeated glucose measurements for patients with initial readings in the DM or IGT range, excluding those with normal baseline values.
  • This approach could miss new cases of DM or hyperglycemia during follow-up.
  • It may have been a cost-saving measure or focused on tracking patients with abnormal readings.

Trends in Blood Glucose Levels During TB Treatment:

• Mean blood glucose levels decreased in patients with baseline values in the DM or IGT range who were not previously diagnosed with DM after starting TB treatment.
• The prevalence of elevated blood glucose also decreased during follow-up, consistent with earlier findings that stress hormones in response to the disease may cause initial high blood glucose levels.
• Some patients experienced persistent hyperglycemia after TB treatment, which may be due to:
  • Undiagnosed diabetes before TB infection.
  • Pre-existing IGT, which develops into DM due to additional insulin resistance from infection.

Cavitary Lung Lesions and Hyperglycemia:

• The development of cavitary lung lesions suggests a severe immune response during TB infection and may be associated with hyperglycemia.
• Glucose values typically improve over time with effective TB treatment.
• Good TB treatment outcomes are achievable in DM patients with adequate glucose control.