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

A.K. CHAKRABORTY ETAL
5% in level 2 & 20% in level 3 will increase DTP
efficiency to 83.44% (column 8, second row from
bottom in Table 7). Other alternative
combinations are also shown in the Table.
Discussion
Introduction of SCC regimens of high efficacy
in DTP in 1983 could be viewed as a measure for
increasing DTP efficiency through improving the
treatment efficiency, DTP efficiency, however, is
not only related to treatment efficiency but to
other variables as well, e.g., case-finding
efficiency (CF efficiency), efficiency of
implementing the SCC regimen policy and,
finally, to regimen acceptance & conformity by
patients (compliance). Through this model, an
attempt is made to demonstrate the role of. some
of these key variables in determining the likely
output from the policy of augmenting treatment
efficiency with SCC, as a lone measure of
increasing DTP efficiency.
DTP efficiency/CF efficiency under SCC .
The model confirms the hypothesis made by
the earlier workers 1,2,3 that given the resources
made available for NTP, improvement in CF
efficiency is a more crucial corrective variable
than trying to change only treatment efficiency
through selective augmented inputs. At the lower
levels of CF efficiency (say 33%), the additional
benefit accruing from SCC over SR is not
appreciable, being below 10% in terms of the
gain in DTP efficiency. Even this extent of
improvement with SCC could result with 100% of
the cases diagnosed in DTP being so treated
which, in any case, may not be. possible in the
foreseeable future. It would require a
substantially higher CF efficiency to obtain still
better results (say 70% CF efficiency will gain
about 15% greater DTP efficiency) with patient
compliance remaining at the currently observed
level (columnV, row one from top and fourth row
from bottom in Table 7). In the unlikely situation
of 100% CF efficiency and 100% cases put on
SCC, the likely DTP efficiency could be 78.9%,
which is the maximum possible under DTP when
the patient compliance remains unchanged. This
could, of course, be compared with the situation
in which 100% CF efficiency and 100% cases
being placed on SR will give DTP efficiency of
49.7 (Table 7), highlighting the benefit from SCC.
Compliance structure and DTP efficiency
The model has shown that treatment efficiency
and DTP efficiency are also directly proportional
to changes in compliance structure i.e.,
proportional distribution of patients complying in
varying proportions at different levels of
compliance. The rates of compliance, no doubt,
are also dependent on the treatment regimen :
The current rates of compliance at levels 1 & 2,
are high both for SR and SCC. In the model
developed by Radhakrishna 2 , compliance at
level 4 has been taken as the overall extent of
case-holding efficiency, ignoring the rates of
compliance at other levels. Under the
circumstances, the resultant DTP efficiency of
8%, worked out by him may not represent the
actual DTP efficiency because some cases in
levels 1, 2 and 3 do convert to a stable smear
negativity 1,12 . This has been demonstrated by the
model developed by Srikantaramu et al 1 , still later
by Radhakrishna 3 and now through the use of the
factor of compliance structure.
Apart form chemotherapy, another factor
utilised in the model constructed by Srikantaramu
et ai ] contributing to sputum conversion was the
phenomenon of “self-cure”. The annual
proportion of self-cures occurring naturally has
been estimated to be 20% of the total cases in the
community, in an epidemiological survey 13 and,
understandably, the information on self cures
amongst tuberculosis cases attending clinics is not
known. If “self cure” is applied to cases in the
lower levels of compliance (levels 1, 2 and 3),
then sputum conversion should be in excess of
20%, even in level 1. The observed sputum
conversion of about 22% in level 1 under SR,
therefore, could possible represent “self cure”
(Table 1, column 4).
It is interesting to study the effect of different
regimen mixes varying with compliance structure
(Table 5). At the regimen mix of situation II, with
90% SR & 10% SCC, raising the current
compliance (column 4) to a very high level
(column 8) would result in an increase in
treatment efficiency of 13.58%. On the other
hand, in situation X, with 10% SR & 90% SCC, a
similar improvement in compliance would give a
5.58% improvement in treatment efficiency.