1 in 4 patients resistant to any one of 13 TB drugs, says govt report

One of four patients grappling with Tuberculosis has developed resistance to at least one of the thirteen drugs available to treat the scourge on this date. Alarming insights have emerged as for the first time ever, India has conducted a national drug-resistance survey (NDRS), a survey of patients to know which TB drugs do not work on them and why. 

The survey that was started in 2014 and culminated in 2016, has been released after four long years and with startling results. “More than a quarter of TB patients in India have drug resistance to one or the other anti-TB drug,” it states.  

This is the largest ever conducted by any country in the world and the first ever survey having drug susceptibility testing (DST) for 13 anti-TB drugs. 

5280 sputum samples of TB patients were put through drug-sensitivity tests on culture growth at National Institute for Research in Tuberculosis (NIRT) in Chennai. It shows that in close to 28% (1479) patients there is resistance to any first or second line TB drug. “Any drug resistance among new TB patients was 22.54%, with 36.82% among previously treated TB patients and 28.02% among all patients,” it says. 

In a glaring gender gap, 72.01% of the survey participants were males and 27.99% were females. 

And only 1.7% were children from 0 to 14 years. Also, more than 60% females were less than 34 years, indicating the vulnerability of young women to catch TB. 

Isoniazid and Pyrazinamide are basic drugs for the treatment of TB. But the survey found that 11.06% new patients and 25.09% relapse patients were resistant to Isoniazid. Also, 6.95% new patients and 8.77% old patients were resistant to Pyrazinamide. 

6.19% patients were resistant to more than one drug. That is they had multi-drug resistant (MDR)-TB. “Of all newly diagnosed TB patients, 2.84% were resistant to more than one drug, which is they are multi-drug resistant (MDR). In those cases, which have previously been treated for TB and have relapsed again, the drug-resistance shot up to 11.60%,” states the report. 

Among 307 MDR-TB patients, 21.82% (67) were additionally resistant to fluoroquinolone and 3.58% (11) to any second-line injectable drugs. Those that are resistant to second-line injections drugs are known as extensively drug-resistant (XDR) category of patients. 

“Fluoroquinolone resistance among MDR-TB patients is high, notes the study. The survey results clearly indicate that drug resistance is present in all settings, and the wide range of resistance patterns from any isoniazid resistance to XDR-TB needs to be addressed with the strengthening of drug resistance surveillance, universal drug-sensitivity test (DST) and appropriate DST guided treatment strategies,” notes the report. 

The epidemiology of DR-TB in India has never been studied nationally. Knowing the epidemiology of DR-TB is essential to guide development of evidence-based strategies to combat DR-TB in India, states the report. 

A state-level analysis of drug resistance indicates that DR-TB is prevalent in all states, albeit with wide variations ranging from 18.42% in Himachal Pradesh to 36.84% in Jammu & Kashmir.

Considering a large number of patients do not respond to one or more TB drugs, setting up and strengthening drug resistance surveillance including using state of art next generation sequencing has been advised in the report. 

“This will provide the programme with the trends of drug resistance, transmission patterns and mapping of hot spots in different states for a better understanding of molecular epidemiology for TB surveillance,” it says. 

Here are other highlights of the survey: 
*Among the 4958 TB patients with DST results, 28% had resistance to one or the other anti- TB drug, while 6.19% had Multi Drug Resistant (MDR) TB. 

*Among the 307 MDR-TB patients, 11 (3.58%) and 67 (21.82%) patients had additional resistance to any drug from second line injectable class and any drug from fluoroquinolone class, respectively; i.e. pre-extensively drug-resistant (XDR) - TB. 

*Among the 78 pre XDR-TB patients, most of the patients (67 [86%]) had additional fluoroquinolone resistance.