Diabetes drug to help treat TB

CHENNAI: A drug widely used to treat type-2 diabetes, metformin, will now be prescribed with a cocktail of antibiotics for patients with tuberculosis as part of the clinical study in select cities by the end of the year, Indian Council of Medical Research (ICMR) director Soumya Swaminathan has said.

Research suggests that metformin, which controls glucose levels, works as a protective agent against TB regardless of whether someone has diabetes or not. “The drug reduces inflammation, enhances immune response and the efficacy of conventional TB drugs. Some research has even shown that it improves control of TB infection and decreases disease severity. We want to see if this will work as adjunctive therapy for improving the effective treatment of TB in our population,“ she said.

Doctors say the relationship between TB and diabetes isn't new. As of now, patients testing positive for diabetes at government facilities are referred to undergo examination for TB. TB patients are also asked to check their blood glucose levels. In 2016, a guideline was framed by the central TB division after studies showed people with diabetes had 2-3 times higher risk of contracting TB. TB patients are also asked to check their blood glucose levels.

A study by Dr Vijay Viswanathan, chief diabetologist at Chennai-based M V Hospital for Diabetes, and University of Massachusetts Medical School found that 54.1% of the 209 patients surveyed with pulmonary tuberculosis were diabetic, while 21% were pre-diabetic. “According to data, every fourth person has latent TB, which surfaces when the immune system is weak,“ said Dr Viswanathan. “Diabetes increases the risk of progression to active TB disease in people infected with Mycobacterium tuberculosis, the bacteria that causes TB. Conversely, TB has an effect on diabetes. It can not only worsen blood sugar control but also complicate clinical management of diabetes.The TB-diabetes combination is as bad as TB and HIV,“ he said.

Now, scientists say, adding metformin, even if the patient's sugar levels are normal, may not just prevent or delay diabetes, but also improve outcomes of TB treatment. So, a select group of people will receive the drug during the five-day antibiotics treatment.

Last year, the World Health Organization increased its estimate of the number of new TB patients in India to 2.8 million in 2015 compared to 2.2 million in 2014. India, now, is home to more than a quarter of the global TB population.

A bacterial disease commonly affecting the lungs, TB can be cured using a cocktail of antibiotics for six months. These drugs are available for free in India which, however, hasn't been able to drastically bring down infection rates due to lack of awareness and access to treatment.

The Indian Revised National Tuberculosis Control Programme uses thrice-weekly treatment with standard drug doses. Recently, scientists trying to find out reasons for poor outcomes studied 1,912 adult TB patients receiving anti-TB treatment in Chennai and found the concentration of rifampicin, isoniazid and pyrazinamide in the blood inadequate in a majority of the population. Rifampicin was inadequate in more than 90% of the population. “We have now increased the treatment to five days a week.We are hoping it will make treatment effective and reduce risks of drug resistance. It has rolled out in five states. By the end of the year, it will be the standard for people across the country,“ Dr Swaminathan said.