Published in The Hindu on October 21, 2012
Tuberculosis was declared a global health emergency in 1993, but it has been growing unchecked. Today, TB is causing millions of deaths every year globally. Like any infectious disease, TB is prevalent even in developed countries. But it is a more serious problem in the developing and populous countries.
India and China together account for nearly 40 per cent of the global burden. The World Health Organisation’s Global Tuberculosis Report 2012 reveals the magnitude in the two countries, and why India has the most number of patients . In India, the prevalence is 3.1 million at best and 4.3 million at high. In China, the figures are 1.4 million and 1.6 million respectively. Even in prevalence rate (per one lakh population a year), India is 249 at best and 346 at high. China fares better: 104 at best and 119 at high.
In 2011, India again topped the list for incidence (the number of new cases detected in a year). It had 2 million to 2.5 million, compared with China’s 0.9 million to 1.1 million. If global incidence during 2011 was 8.3 million to 9 million, “India and China accounted for 26 per cent and 12 per cent respectively,” the WHO report notes. Mortality is also high in India. About three lakh people will die this year.
There are other differences between China and India. The percentage of TB patients who are also HIV positive is 6.5 in India; China’s figure is 2.3 per cent. This could be because only 23 per cent of TB patients were tested for HIV in China compared with India’s 45 per cent.
There is a significant, but apparent, reduction in prevalence and mortality when compared with 1990 levels. Increases in treatment success percentages have been registered for new cases — from 25 per cent in 1995 to 88 per cent in 2010.
According to the WHO report, the detection rate for new and relapse cases is almost the same in 1995 and 2011 — 58 in 1995 and 59 in 2011. But it was 71 per cent in 2011 among new sputum positive (NSP) patients alone, notes a May 2012 paper in the Indian Journal of Medical Research .“TB case-finding has stalled,” warns the draft executive summary of the Joint Monitoring Mission.
More than one lakh patients are put on treatment each month. The case detection, incidence, prevalence and treatment success figures are based on data drawn from the Revised National Tuberculosis Control programme (RNTCP). “…Early and effective TB treatment and control is difficult in India with its current tools and systems,” notes an editorial in IJMR (March 2012).
According to the May 2012 IJMR paper, only 30,000 private practitioners and 15 corporate health facilities are providing RNTCP services. Continuing the programme without the participation of all private practitioners has been its weakness. This despite the fact that the government is aware of the reality — private practitioners are the first point of contact for a majority of patients.
But private doctors are ill-equipped to track and follow up all patients and ensure treatment adherence. Resorting to unreliable tests, particularly serological (blood) tests based on antibody response to diagnose active TB, and some doctors relying exclusively on X-rays, have added to the challenge. Finally, the Directly Observed Treatment, Short-course (DOTS) is a passive system: it does not seek out patients but waits for them to walk in and get tested. Delayed diagnosis, faulty treatment, lack of follow-up, use of wrong diagnostic tools by doctors, and giving up on treatment mid-way often result in patients infecting others and developing resistance to drugs.
According to a recently published paper in the journal Health Policy and Planning , drug resistance surveillance surveys undertaken in Gujarat and Chennai indicate that there are “1-3 per cent MDR-TB [multi-drug resistant-TB] among fresh pulmonary cases… and 13-17 per cent among previously treated cases.” If detecting and treating all TB patients who are not drug resistant is challenging enough, detecting and treating drug-resistant TB is riddled with problems.
The government has woken up. After it took some dramatic and bold initiatives over the last one year, TB detection and management is no longer the same. In June 2012, the government banned serological tests. There are plans to go out and test certain target groups. But the landmark decision was making TB a notifiable disease. This has made it mandatory for laboratories, hospitals, nursing homes and doctors, both in the public and private sector, to report every TB case detected. The government system would kick in once a case is notified to ensure correct diagnosis and complete adherence to treatment during the entire duration of treatment. Two important panels have made recommendations to engage the private sector in multiple ways to rein in TB.
The government dragged its feet for too long and remained in a state of denial till the spectre of multi-drug resistant TB, high prevalence and missing out of a huge number of patients made it too difficult to avoid making it a notifiable disease.
As most patients first approach the private sector for treatment, the true incidence and prevalence levels are never known. Evidently the government delayed the decision principally because once TB is made notifiable, and when the requirement is fully and effectively implemented, the true incidence and prevalence of all forms of TB will come to light. As the executive summary notes, “approximately one million TB cases per year are unreported.”
This is where the approaches that India and China adopted to fighting TB diverged. Of the 37 notifiable diseases in China, TB ranks No. 1. It pulled out all the stops by 2000. “The concept of acceptance of the problem, identifying its requirement and the political will of TB eradication has set China on a progressive path,” notes a paper published in the journal Interdisciplinary Perspectives on Infectious Diseases .
Notification and treatment will not have a significant impact until the TB control programme starts using new WHO-approved diagnostic tests. Smear microscopy used for sputum sample study is a 125-year-old method. Aside from its low sensitivity (50 per cent), it cannot determine drug resistance. Xpert MTB/RIF, on the other hand, has 72 per cent sensitivity with one test, and 90 per cent with three tests in the case of smear-negative patients. The sensitivity goes up to 98 per cent in the case of smear-positive and culture-positive patients. Xpert MTB/RIF has 99 per cent specificity. It can turn in results in less than two hours compared with four to six weeks in the case of the culture process.
But the most important advantage is its ability to diagnose rifampicin drug resistance. Rifampicin resistance is a brilliant marker of MDR-TB. Most patients who are resistant to rifampicin are also resistant to isoniazid. Resistance to at least rifampicin and isoniazid are required to classify a person as an MDR-TB patient.
Widespread use of such diagnostic tools that provide quick and accurate results and also indicate drug resistance will go a long way in battling the epidemic.
The diagnostic tool is being used in a couple of pilot test centres. The TB control programme should quickly evaluate its performance and use it more widely after bargaining for a cheaper price. Strengthening the programme to treat more number of drug-resistant patients should go hand in hand with that strategy.
But there is way to go before the challenge is surmounted credibly and effectively.