A tale of two treatments
In the treatment of TB, the intensive periods under standard regimen (SR) and shorter course chemotherapy (SCC) remain constant at two months, after which the patient turns sputum negative. The length of the treatment is reduced in the follow-up phase from 10 months to four. This fact is significant because most of the default occurs immediately after the intensive phase. Therefore, shortening the follow-up phase mayor may not lead to a reduced rate of defaults.
Moreover, in case a defaulting patient comes for treatment, he is given an additional drug for overcoming the resistance that may have developed during the partial treatment taken earlier. Thus, under SR, where initial treatment was with two drugs, the retreatment is done with three. Under SCC, the initial treatment is done with four drugs and retreatment with five.
These five are virtually the only drugs available for ambulatory approach. Therefore under SR, in case of second and third defaults, one drug each can still be added on and the ambulatory treatment continued. On the other hand, in case of a second default in SCC, patients have to be put on more potent and prohibitively expensive treatment.
Also, the drug costs under SR is Rs 182.50 for new patients and Rs 632.50 for old patients. Under SCC, this is Rs 837 and Rs 1,047 respectively. This is mostly owing to persistent use of expensive bactericidal drugs like rifampicin, pyrazrnamide and streptomycin and to the replacement of inexpensive thiacetazone by ethambutol. It is acknowledged that thiacetazone is more toxic in AIDS patients, but it has been well tolerated, at least in most parts of India.
The wisdom behind India's revised national TB programme, whose main plank is SCC, is based on the contention that SCC is more cost-effective than SR in all situations; actually, SCC is cost-effective only in hospitalised treatment which, incidentally, is not relevant to India.
For default after a specified period, the cure rate has been calculated to be higher under SCC as compared to SR, assuming that default rates as a function of a month's treatment will remain unchanged under SR and SCC. But the annual report of the New Delhi TB Centre (1979) shows that more than So per cent of the default occurs within the first three months.
The World Bank supported estimations for cure rates of 60 per cent for SR and 8S per cent for SCC are also not supported by the Indian example. Retreatment has been assumed to be undertaken under the five-drug SCC regimen; however, according to a WHO study, retreatment can be undertaken by a three-drug SR regimen as well.
Convinced by the World Bank about the cost-effectiveness of SCC, the government has made provisions for the purchase of expensive high-potency drugs under the regimen, leaving the organisational weaknesses unattended - a possible prescription for increased drug resistance. The obvious beneficiaries are the drug companies. And the cost, increased virulence and incidence of TB.