Tuberculosis (TB) has recently made headlines in the U.S. And news of these cases remind us once again that TB is far from conquered. This disease infects about 8.6 million people every year and kills 1.5 million, more than any other infectious disease except human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS).
Increasingly, TB’s spread is fueled by rising rates of diabetes—as with HIV, diabetes weakens the immune system, making a person more vulnerable to TB infection and illness—particularly in emerging economies like India and China, which are the source for much of the TB seen in the U.S.
Globally, it is now estimated that 15 percent of people who develop TB are also living with diabetes — equating to over 1 million people worldwide. We appear to be ignoring this trend at our peril. TB and diabetes need to be addressed together — immediately. If not, this problem will grow to epidemic proportions and ultimately claim the lives of millions.
Rising Global Rates of Diabetes
Diabetics have difficulties in processing insulin. This dysfunction weakens their immune system and makes them more susceptible to contracting TB, which is an airborne bacterial infection.
Most people living with a TB infection never develop the full-fledged disease. But a weakened immune response makes it easier for TB bacteria to turn “active,” making it contagious and potentially fatal.
In fact, having diabetes increases a person’s chances of developing the fully fledged TB disease by two to three times. And global diabetes rates are rapidly rising. Over the next three decades, the total number of people with this illness is expected to jump from just under 400 million to nearly 600 million. That rise will fuel TB’s spread.
Already, countries with the highest TB rates are also suffering from severe diabetes burdens.
Sub-Saharan Africa, for example, has the highest concentration of TB in the world. And over the next two decades, the region’s diabetes rates are expected to jump by over 100 percent.
Likewise, over half of the countries predicted to have the highest diabetes rates by 2035—China, India, Brazil, Indonesia, Pakistan, and Russia—also have the highest rates of TB. These are countries with historically high prevalence of latent TB infection, have large urban centers that facilitate transmission of TB disease, and are experiencing the changes in diet and lifestyle that predispose individuals to diabetes. In some parts of India, evidence suggests that one out of every five people with TB also has diabetes.
It’s evident that the global diabetes epidemic now threatens to undermine the tremendous progress we’ve made against TB. Since 1990, the global TB mortality rate has been cut by almost half. This pernicious cross-partnership threatens to boost it back skyward.
The global health community must act. And the first step is for health care providers in high TB areas to implement what’s called “bidirectional” screening. This protocol simply requires that any patient that tests positive for TB be referred for diabetes testing, and vice versa. This ensures patients suffering from TB and diabetes receive the proper treatments. Their diseases can be managed and prevented from accelerating negative effects.
Global health officials have witnessed such a deadly partnership before. Back in the early 90s, TB and HIV/AIDS worked together in a similar way, with the latter weakening people’s immune systems and making them more susceptible to infection. HIV/AIDS helped quadruple the number of TB cases in many parts of Africa.
Despite ample evidence of this relationship, international officials failed to act quickly. It took years for them to mobilize. Finally, the World Health Organization declared an emergency, integrated its treatment protocols, and started to drive down infection rates. The solution was straightforward and essentially mirrors the bidirectional screening now needed for TB-diabetes: provide HIV counseling and testing for people diagnosed with TB, provide TB screening for people living with HIV/AIDS, followed by appropriate care that is convenient for patients to access.
There was a severe human cost to this lag. Poor countries suffered greatly. In Swaziland, which has the world’s highest rate of TB-HIV co-infection, average life expectancy dropped from 59 years in 1990 to a low of 46 years in 2004.
In November, the Indonesian Ministry of Health, together with the World Diabetes Foundation, the International Union Against Tuberculosis and Lung Disease, and leaders from the United States and other countries will co-host a summit in Bali to catalyze the action needed to fight TB and diabetes together.
They’ll take lessons learned from health officials in countries like India, which has begun piloting bidirectional screening, so they can replicate those activities in their home countries. In southern India especially, clinics have begun reporting high yields of patients diagnosed with diabetes and TB through bidirectional screening. By convening now, these leaders are attempting to do something that we see too little of these days: to get out in front of a looming epidemic before it does its worst damage.
The global health community must not let history repeat itself. The relationship between diabetes and tuberculosis is clear. Now is the time for action, starting with bidirectional screening in places where it’s needed most.