Tuberculosis is a disease of antiquity that claims nearly 1,000 lives every day in India. There are serious challenges that continue to exist in the TB landscape. One of these is drug resistance to anti-TB drugs. Though drug resistant TB has been in existence for long, it has lethal forms that continue to emerge and threaten to undermine the extensive work undertaken to prevent and control the spread of TB.
Drug resistant TB is a man-made problem, the result of treatment mismanagement due to which the TB bacteria develops resistance to the two or more most commonly used drugs in the current four-drug (or first-line) regimen, leading to multidrug-resistant TB (MDR-TB). In some cases, this mismanagement can transform itself into extensively drug resistant TB (XDR TB), where the bacteria do not respond to even second line drugs. This poses a serious threat to global TB control. To make matters worse, an advanced form of drug resistance has been reported recently in India. It is known as extremely drug resistant TB (XXDR-TB). In this form of the disease, none of the known TB drugs or their combinations work.
A study
The reasons for the rise in drug resistance are many. In most instances, detection of the disease is delayed due to the non-availability of good diagnostic laboratories and patients receiving treatment with non-standardised and arbitrary drug regimens of questionable quality. There is continuous use of incorrect diagnostics like serological tests for detecting TB which are utilised in the private sector. Though the World Health Organisation (WHO) has recommended the ban on the use of these tests, $15 billion is being spent annually in India on these. A recent study carried out by the All India Institute of Medical Sciences (AIIMS) concludes that serological tests can detect the disease only in a quarter of TB patients while three-fourths will be wrongly diagnosed as non-TB cases, even if they are smear positive. In other words, most who have the disease will be diagnosed as healthy, and most healthy persons will be diagnosed as TB infected patients, if serology alone is relied upon.
Although drug resistant TB in India has been reported frequently during the last four decades, the available information from here is incomplete. Most patients are not notified to the Revised National Tuberculosis Control Programme (RNTCP) and many treatment outcomes remain unknown. Recently, the Central TB Division (CTD) has taken a policy decision to make it mandatory to notify all TB cases — a positive step.
Treatment costs
MDR-TB can only be treated with second line drugs which are very expensive. The treatment course is very long and expensive. It is vital to have mechanisms of appropriate regimen and ensuring access to quality assured drugs. Self-prescription of anti-TB drugs promotes drug resistance. This is made worse by the lack of regulation in accessing these drugs. Treatment of MDR TB commences after detection, a process that takes many months when conventional methods are used. As a result, patients with MDR- or XDR TB continue to spread the infection to others. Drugs used to treat MDR- and XDR TB are toxic and expensive when compared to those used in the treatment of basic TB. While a course of standard TB drugs costs approximately Rs.1,000, MDR-TB drugs can cost more than Rs.1 lakh. XDR-TB treatment is far more expensive. The need of the hour is not only detecting drug resistant strains early, but also initiating measures for optimising disease management and care so that each patient is diagnosed quickly and treated appropriately.
The RNTCP has had some important successes including targeting an 85 per cent cure rate and 90 per cent diagnostic coverage. As the monthly monitoring of providing treatment under Directly Observed Treatment, Short course (DOTS) is done, its effectiveness needs to be enhanced.
In many instances the national programme has faltered in diagnosing and treating drug resistant TB. In India, the RNTCP provides treatment to TB patients on alternate days, instead of daily treatment.
This poses a higher risk for patients to miss doses, another key factor leading to the creation of drug resistant strains of TB. The TB programme should create treatment protocols that are simple to adhere to and are supported by treatment counselling.
Importance of private sector
The engagement of the private sector has remained unsuccessful by the government. This is worrying as close to 50 per cent of a TB patient’s first point of diagnosis and treatment is the private sector. Many physicians in the private sector and some in the public sector do not follow international norms of treatment. The engagement of hospitals is also vital to curb the emergence and spread of drug-resistant TB.
The prevention of drug resistant TB relies heavily on the effectiveness with which control efforts will succeed to treat TB patients in both the public and the private sectors. The programme cannot rest on its success; it must take a multi-pronged approach to TB control. If not, India must prepare itself to address growing drug resistance, rising treatment costs and extreme human suffering from what is a preventable and easily treatable disease.
(Dr. Sarman Singh is Faculty-in-charge, Microbiology, Department of Laboratory Medicine, AIIMS, New Delhi. The views expressed are personal.)
