Breaking the TB-diabetes nexus for a healthier India

Dr Sophia Thomas, CNS Correspondent, India
Source: World Diabetes Foundation
On the occasion of World Diabetes Day  2017 (November 14), Dr Soumya Swaminathan, WHO Deputy Director General and Director-General of Indian Council of Medical Research (ICMR), called for a standardised approach to tackle non-communicable diseases (NCDs) similar to the Indian government’s Revised National  TB control programme (RNTCP). Interestingly, there is a synergistic linkage between the two diseases which share some common risk factors.

TB is the 9th leading cause of death worldwide. The WHO Global TB report 2017, estimates that 10.4 million people fell ill with TB in 2016, about 56% of whom were in five countries: India, Indonesia, China, Philippines and Pakistan. With 28 lakh patients infected with TB (and 4.23 lakh deaths) in the country in 2016, India accounts for one fourth of the global TB burden. While the RNTCP reports a decline in the incidence and mortality of TB, the growing prevalence of diabetes mellitus in the country poses new threats to TB control. There are 425 million people with diabetes in the world, with 50% of them remaining undiagnosed. The prevalence is growing, particularly in low- and middle-income countries, with India among the top three countries with 73 million people living with diabetes.

Rates of TB are higher in people with diabetes than in the general population. In fact, diabetes triples the risk of TB. Therefore, India is reeling under the convergence of these two diseases. Speaking at a webinar hosted by CNS on Diabetes and latent TB, active TB disease, MDR-TB, tobacco smoking, Dr Anil Kapur, Chairman, Board of Directors at the World Diabetes Foundation gave a historical context to this convergence. He stated that the association of diabetes and TB is not new. Before 1960, when treatment for diabetes and TB was not easily available, it was said that the patient would die of ketoacidosis and if he/she survives, would die of TB. The last 30 years have seen a surge in diabetes cases in TB endemic countries like India and China, resulting in a mixed trend of people exposed to TB having diabetes.

Tuberculosis-Diabetes Mellitus continuum

Common risk factors

Tuberculosis and Diabetes Mellitus (type 2) have common risk factors: tobacco use, alcohol consumption and poor nutrition. These risk factors are modifiable, which emphasizes the role of prevention for both these diseases. Dr Kapur highlighted common socioeconomic factors such as people living in urban slums of megapolises, where TB lurks around. There is growing evidence that the urban poor in India are also at greater risk of developing diabetes. The risk of this dual disease burden will further deepen the inequities faced by the urban poor.

In explaining the influence of diabetes and TB on each other, Dr. Kapur elicited the following points:

● ‘Diabetic immunopathy’ compromises the immune system, increasing vulnerability to TB infection. Conversely, TB infection can accelerate the onset of diabetes in people with prediabetes and worsen the glycaemic control in those living with diabetes.
● Diabetes increases the risk of active TB, latent TB and MDR-T
● In India, prevalence of active TB in people with diabetes is 7-8 times higher than in general  population
● Prevalence of diabetes among TB patients is 2-3 times more than in the general population, with many being diagnosed during active TB testing
● Diabetes increases the risk of adverse TB outcomes - delayed sputum conversion (so they continue to spread infection), higher relapse rate and higher death rates during active TB, and it is now being learnt that they also have high risk of MDR-TB.

Dr Surya Kant, National President of the Indian Chest Society and Professor and Head, Respiratory Medicine department, King George's Medical University, during the webinar impressed upon the following points:

● TB is the second most common infection that a person with diabetes can acquire
● Hyperglycemia favours growth, viability and propagation of TB bacilli

The above facts evoke an urgency and a call to action by the Indian government, health professionals, individuals and organisations working to improve the health and wellbeing of the nation.

Challenges and way forward

On a positive note, the Indian government has acknowledged this association and has introduced a National framework for joint TB-Diabetes collaborative activities. As is with any policy framework, implementation is crucial. Dr Kapur points out that there is a long way to go for this, especially for the policy to take effect at the grass roots level. Creating awareness about the deadly interaction of the two diseases among the vulnerable population, especially among the urban poor, is a vital prevention strategy. Considering the enormous nature of this dual disease burden, building capacity among the health workforce is essential.

Dr Sophia Thomas, Citizen News Service - CNS
November 28, 2017

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