India’s diabetes epidemic is making its widespread TB problem worse

General Studies Paper 2

CONTEXT

• Diabetes mellitus is a major risk factor that increases the incidence and severity of tuberculosis. Also tuberculosis co-infections adversely affect tuberculosis treatment outcomes in a patient. Among people with TB, the prevalence of DM was found to be 25.3% while 24.5% were pre-diabetic.

THE DOUBLE BURDEN

• Long before COVID-19 devastated us, India has been experiencing the double burden of two debilitating and severe epidemics – type 2 diabetes (a.k.a. diabetes mellitus, DM) and tuberculosis (TB).
• Currently, India has around 74.2 million people living with diabetes while TB affects 2.6 million Indians every year. Yet few know how deeply these diseases are interlinked.
• The evidence is clear: DM increases the risk of developing respiratory infections.
• We also know DM is a major risk factor that increases the incidence and severity of TB.
• Also, DM and TB co-infections adversely affect TB treatment outcomes in a patient.
• The worry is that among people with TB, the prevalence of DM was found to be 25.3% while 24.5% were pre-diabetic, in a 2012 study in tuberculosis units in Chennai.

DM INCREASES RISK OF TB

• DM not only increases the risk of TB, it also delays the sputum smear and culture conversion of an individual affected by both diseases.
• DM impairs cell-mediated immunity; uncontrolled DM affects the cytokine response and alters the defences in the alveolar macrophages.
• As people with diabetes have already compromised immune function, the risk of TB infection is high. They will also have a higher bacterial load.
• Individuals with TB and DM are more likely to have cavitary lesions in lower lung fields.
• A 2016 study revealed that the TB-DM group showed reduced lung functioning after TB treatment completion compared with the TB non-DM group.
• DM also increases the likelihood of unfavourable TB treatment outcomes, such as treatment failure, relapse/reinfection, and even death.
• So people with DM and TB suffer more severely and must fight harder to survive – illustrating the greater impact of the twin burden of DM and TB not just on patients but also on the healthcare system, their families, and their communities.

DM MAKES TB DIFFICULT TO CURE

• In individuals affected by both diseases, the lungs are severely affected.
• Persistent inflammation has also been seen in people with DM and TB – even after they have completed their TB treatment.
• Experts have reported that TB-related respiratory complications have been a common cause of death among people with TB and DM, but which wasn’t the case with people with TB only.
• DM directly affects the outcomes of those affected by both diseases. A higher fraction of unfavourable TB treatment outcomes occurred among people with low body-mass indices and with low glycated haemoglobin levels (better known as HbA1c) compared to people with low BMI and high HbA1c.
• This indicates that one’s nutritional status is important for favourable TB treatment outcomes.
• It also showed that the most common cause of deaths were respiratory complications (50%) followed by events related to cardiovascular disease (32%) in those affected with TB DM as compared to TB only (27% and 15%).

SUGGESTIONS

• For starters, we need to provide integrated and patient-centred (i.e. more individualised) care for people suffering from both TB and DM, as well as other comorbidities.
• It is time to turn to evidence from studies to establish mechanisms to coordinate DM and TB diagnosis and treatment, including bidirectional screening of TB and DM, patient education and support, and DM treatment in new TB cases.
• An important part of this is to improve the nutritional status of people with TB as well as DM, as this can help increase the chances of favourable TB-treatment outcomes.
• It is important to intensify high-quality care for TB, DM and other associated comorbidities as part of holistic treatment plans, and to strengthen individual programmes for TB and DM as a priority.
• We need to build and scale up resilient and integrated health systems.
• This will require increased commitment from stakeholders, develop stronger policy guidance as well as the mobilisation of additional resources to be able to support the development of such systems.
• Also we need to build on the TB-DM research literature, since better decision-making will require access to better data.

WAY FORWARD

• Studying the nature of interactions between the two diseases and developing appropriate response strategies must be a priority for health professionals, and will benefit patients suffering from both diseases as well as help make communities at large more aware of the impact of their interrelated impact.