Link between diabetes and TB

Dr P S Sarma, CNS Correspondent, India
Diabetes Mellitus (DM) is one disease that can have an adverse affect on many organs of the body. Like wise, it has a great impact on all forms of TB—whether latent or active . People with DM have a high risk of getting TB, more so if they are having  poor diabetes control. Diabetes prevalence is increasing especially is low income settings where TB is already endemic.

A first ever population based study of its kind done in the USA by Dr Leonardo Martinez, involving 4215 participants, found that TB prevalence in people with no diabetes was 4.1%, in those with pre diabetes it was 5.5% and in those with diabetes it was 7.6%. Overall tuberculosis prevalence in the entire sample was 5%. The study also found that diabetes (and pre-diabetes) increases risk of latent TB infection. Usually the risk for people with diabetes to get latent TB goes up two times but higher risk was found for those with poor glycaemic control.

There is  enough evidence that DM and poorly managed DM increases  risk of TB infection.  Also, poor diabetic  control enhances TB infection. Other  reasons are tobacco smoking and consumption of alcohol. Socio economical determinants like poverty, malnutrition, etc also need to be addressed.

Cohort studies done in multi countries show that TB was more likely to increase in low and  middle income countries when DM prevalence  increased. For example, in India during 1998-2008 growing  prevalence of  DM increased the annual no of TB cases in diabetics by 46%.

DM increases the risk of active TB by about 3 fold.  It also increases adverse TB treatment outcomes -i.e  delayed  sputum  conversion, higher relapse rate and higher death rate.  Drug –Drug interaction too can complicate TB treatment. In short undiagnosed, or inadequately treated  and poorly controlled DM is a big threat to TB prevention and control .

WHO has given a collaborative  frame work  for care and control of TB & DM. All TB cases are to be tested  for their blood sugar levels, and all people with diabetics with symptoms, like cough, need to be evaluated for TB.

Considering the effect of smoking  on TB , it accounts  for 80% of all TB cases world wide. In a study to gauge the effect of smoking on TB, it was observed that smoking more than 10 cigarettes per day was significantly  associated with TB recurrence.

DM increases  risk for progression from latent  TB infection (LTBI) to active TB disease and complicates the treatment of active TB. Apart from TB, DM patients are also more susceptible to a range of infections, like urinary  tract infections, skin & soft tissue infections, lung infections & foot infections.

TB, DM and smoking are the major health problems in our country and  globally. 34.6% of adult population in India are tobacco users. People  with TB who are smokers need to be counselled for smoking cessation. Uncontrolled DM affects the overall  treatment outcomes for persons  with active TB. So for optimum treatment outcomes DM  must be  controlled.

Close monitoring, proper care and management are essential to achieve good cure rates for TB.

Dr PS Sarma, Citizen News Service - CNS
3 November, 2017