ManilaMed pulmonologist Dr. Jose Sarenas III, in a recent forum on tuberculosis (TB), said that lack of education and misconceptions about treatment of the disease among the general population and even the medical community remains as a top concern in curbing tuberculosis mortality.
The results of a Department of Science and Technology 2016 National TB Prevalence Survey show that, despite the ready availability of TB-killing antibiotics, the disease remains as the eighth leading cause of illness and death in the Philippines, and the country is among the 22 countries in the world with the highest TB burden.
Tuberculosis is a contagious infection that usually attacks the lungs. It is caused by a type of bacteria, called mycobacterium tuberculosis, that spreads through air. Its most common symptoms include a bad cough that lasts two weeks or longer, chest pain, weight loss, lack of appetite and coughing up blood or sputum.
There are those that have been infected by TB bacteria but are not ill with the disease (latent TB infection), and those that are able to spread the bacteria to people who they have active interaction with (active TB disease).
Most TB-disease deaths occur in low- and middle-income provinces, but key cities like the National Capital Region have been recorded with the most number of TB cases because of overcrowding.
To date, there are two tests to detect TB bacteria in the body: the TB skin test and TB blood tests. Additional tests include chest x-ray and sputum sample.
A long running initiative, called DOTS (directly observed treatment short-course), has had some success in combating TB mortality. However, Dr. Sarenas noted that DOTS clinics tend to treat or turn away patients based only on the results of the Acid-Fast Bacili (AFB) smear test for TB, but this has proven an unreliable test.
An observation backed by the 2016 study shows that “the estimated prevalence rate of pulmonary TB in the country is 1,159 per 100,000 population. The estimated prevalence of TB using smear positivity alone is 434 per 100,000.” The test misses over half of positive TB cases.
The test is also not disease specific. A research done by the National Center for Biotechnology Information notes that non-TB related lung diseases “often has AFB smear positive sputum results, and physicians may prescribe unnecessary antituberculous drugs for these patients.”
“Some antibiotics are being misused, like the fluoroquinolones. They are being given left and right, without knowing if the patients really need them. It can induce some form of drug resistance if you don’t know the patient has TB. We tend to avoid using those antibiotics [unless explicitly necessary], but that’s just among specialists. However, general practitioners and other MDs [doctors of medicine] who are not knowledgeable about that still tend to give that class of antibiotics. It is contributory to the development of drug resistant TB,” Sarenas said.
According to Sarenas, in the Philippines doctors prescribe this class of antibiotics frequently for conditions, such as upper respiratory tract infection, urinary tract infection and gastro-enteritis, even when these are not the appropriate first option or, worse, not applicable at all, such as in viral infections. While he stressed these are absolutely necessary for a lot of applications, they need to be used responsibly to preserve their efficacy and to not induce the mutation of drug-resistant bacteria.
Drug-related TB already exists but, currently, a mere 4 percent to 5 percent of all TB cases are of the drug-resistant variety. Poor adherence to medication also contributes to the high mortality rate of the disease. “In the 1960s the treatment for TB was just one or two drugs. However, in the 1970s and 1980s, because of poor adherence to treatment protocols, ’yung TB nagiging matapang. And sometimes, the disease is caught quite late, like when the TB has spread to the brain causing TB meningitis. That’s fatal or when it has spread to the bones.”
Since the development of the first anti-TB antibiotic in 1946, the pharmaceutical industry has had to stay ahead of the progressively stronger strains of TB by developing new drugs to combat new strains.
The war on TB is one that has yet to be won resoundingly. Dr. Sarenas stressed, “In light of the latest result we have on TB prevalence, we still have a long way to go when it comes to controlling TB. Vigilance is important, and the careful, meticulous prescribing of antibiotics should be emphasized.”