How diabetes worsens TB, causes treatment failure and death

New Delhi, Aug 5 (IANS) Diabetes continually weakens the immune system, leading to poor health and a high risk of death among patients with tuberculosis (TB), said experts on Tuesday.

The link between TB and diabetes -- two critical challenges to global health -- has long been established. TB and diabetes, both separately and combined, significantly affect individuals, communities, and healthcare systems worldwide.

India's TB burden remains a major public health challenge, with 28 lakh TB cases -- accounting for 26 per cent, the highest globally in 2024. The country also reported an estimated 3.15 lakh TB-related deaths, accounting for 29 per cent of the deaths globally.

The burden of diabetes is also consistently increasing in the country, with over 100 million people currently living with the disease.

“Diabetes weakens the immune system, increasing the risk of TB. Diabetes further compromises the already weakened immune system of people who have TB, leading to poor blood sugar control, a higher likelihood of treatment failure, and an increased risk of death during TB treatment (when compared to those without diabetes),” Hemant D Shewade, senior medical scientist, at ICMR-National Institute of Epidemiology, Chennai, told IANS.

A recent paper, published in the journal PLOS One, led by Shewade and team, noted that people with TB and diabetes are two to three times more likely to remain culture-positive, four times more likely to experience a relapse after completing treatment, and five times more likely to die compared to those without diabetes.

The TB treatment also complicates the management of glucose levels, thus diminishing the effectiveness of the disease management.

Shewade highlighted the need to improve documentation of monitoring glycemic status among people with TB and diabetes, especially those notified by the national TB programme.

Currently, under the programme guidelines, the management of diabetes is the same for those with TB and those without TB.

But, “more evidence is needed on whether one should target strict glycemic control (HbA1C below 7 per cent) or glycemic control that is not strict (HbA1C below 8 per cent) is sufficient. More evidence is needed on whether insulin should be added for all people with TB-diabetes irrespective of the glycemic control status,” the senior scientist told IANS.

In addition, the paper also suggested the capillary fasting blood glucose (cFBG) test to assess the glycemic status of a person with TB-DM.

Further, studies have shown a 3.5-5.0-fold higher risk of TB in diabetes patients, which is especially high in those with type 1 diabetes.

These patients also have high relapse rates after antitubercular drugs and high mortality in case of delayed diagnosis. The World Health Organization (WHO) recommends that patients with diabetes and a cough of more than two weeks need further evaluation for the possibility of TB.

“There is limited information on the prevalence of pulmonary tuberculosis (PTB) in patients with Type-1-diabetes,” Dr. Urvashi Singh, Department of Microbiology, All India Institute of Medical Sciences, New Delhi, told IANS.

Recent research published in the journal Multidisciplinary Respiratory Medicine, led by Singh, along with Dr R. Goswami, and Dr. Randeep Guleria and Dr Abhilash Nair, assessed the prevalence of PTB in 151 patients with type-1-diabetes attending the outpatient clinic in a tertiary-care hospital.

About 10.6 per cent of them showed sputum culture positivity; especially in those with a past history of PTB.

“Thus, there is a high prevalence of PTB in patients with type 1 diabetes in India. They need to be actively screened for PTB by sputum Mycobacterium tuberculosis to initiate early treatment and to prevent transmission in the community,” Singh said.

--IANS

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