The Indian Journal of Tuberculosis - LRS Institute of Tuberculosis ...

Original Article Ind. J. Tub., 1992, 39, 9
SHORT COURSE CHEMOTHERAPY AND EFFICIENCY VARIABLES IN
NATIONAL TUBERCULOSIS PROGRAMME : A MODEL
A.K. Chakraborty 1 , V.H. Balasangameshwara 2 , P. Jagota 3 , T.R. Sreenivas 4 , and K. Chaudhuri 5
(Original received on 19.2.91; Revised version received on 4.9.91; Accepted on 8.11.91)
Summary. The mathematical model presented here
brings out the role of various levels of efficiency in
the performance of key tuberculosis control
activities in the light of the introduction of short
course chemotherapy (SGG) under the District
Tuberculsosis Programme (DTP) in India. It shows
that the potential of DTP could be realised only
when all the Various activities are performed with
a high degree of efficiency; And that SCC alone
cannot appreciably alter the DTP Efficiency
expectations. For example, DTP efficiency with
SCC, even when 100% of patients take more than
80% of the prescribed drugs increases only to 29%
with SCC, over 24% with standard chemotherapy
(SR), if case-finding efficiency (CF efficiency)
remains unchanged at 33%, Which is its current
level. A “critical DTP efficiency” i.e., the efficiency of
the various DTP activities that could lead to
sputum conversion of 85% of the cases diagnosed
requires the performance of key activities at a
high level namely, CF efficiency of 100%, cases put
on SCC 100% a rid the compliance structure of 70%
iii level four and 20% in level three. Thus, DTP
shall have to be geared to meet high performance
requirements to achieve its avowed objectives.
The model gives various levels of expectations
as the outcome of DTP, relating to changes in
efficiency estimates of the key DTP activities.
Introduction
The introduction in District Tuberculosis
Programme (DTP) of short course chemotherapy
regimens (SCC) which have achieved nearly one
hundred percent treatment efficacy in clinical
trials has generated a high degree of expectation
among the planners and programme officers
regarding the role of SCC in tuberculosis control.
The faith in SCC as a tool of tuberculosis control.
however, needs to be viewed in the light of the
earlier hypothesis in respect of standard regimens
(SR) 1,2,3. Thus, in a misplaced perception of
priorities, one may overlook the earlier inference
that was derived from the then mathematical
projection, showing that the overall success in
DTP depended more on increasing the efficiency
of case-finding than that of treatment, per se.
It may be argued, that mathematical
projection of some likely situations (effectvariables)
on the basis of some data on the
simultaneous interaction of multiple variables
may, after all, lead to a thin approximation to the
actual situations because the quantification of
interactions is obtained from separate studies.
Moreover, many variables of unknown magnitude
may be left out on account of failure to conceive
them theoretically and prepare a suitable
hypothesis. Further, confidence intervals of the
effect-variables are difficult to work out,
rendering the task of calculating a curve of
mathematical fit a distinct hazard 4 - There is no
denying the difficulty in the case of chronic
illnesses in obtaining inferences from
observational studies with multiple cross
classifications. It is also realised that this becomes
almost impracticable in the face of increasing
number of variables. However, mathematical
models may be helpful, in this context, in getting
a torrent of data arranged and processed
systematically 5 ’ even though the indiscriminate
inclusion of multiple variables may become
complex and create problems about the
credibility of the inferences. Many scientists,
engaged in the study of the so called “soft
sciences”, including medical sciences like to
construct models, if only to serve as qualitative
1. Additional Director; 2. Bacteriologist; 3. Chief Medical Officer; 4. Statistician; 5. Director, National
Tuberculosis Institute, 8, Bellary Road, Bangalore-560 003.
Correspondence : The Director, National Tuberculosis Institute, 8, Bellary Road, Bangalore-560 003..