EPIDEMIOLOGY <<Back
 
 
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INCIDENCE OF TUBERCULOSIS CASES IN CONTACTS - A SIMPLE MODEL
AK Chakraborty, Hardan Singh & P Jagota: Indian J Prev & Soc Med 1980, 11, 108-11.

Contact examination is not recommended as a routine procedure for Case-finding in the District Tuberculosis Programme. The rationale for not including contact examination as a routine Case-finding measure is: (1) prevalence rate of tuberculosis among the contacts is not much higher than in the general population (2) at the time of diagnosis of an index case, a second case may not be found in the same household. Though more prevalence cases cannot be diagnosed by contact examination, is it possible that by keeping the household contacts, as a group, under surveillance, future incidence of cases in the community can be substantially prevented? A model situation has been created by using hypothesis derived from various studies conducted in India, designed to answer the question. Variables used in the model are: 40% of the general population are infected at any point of time, there is only one prevalence case of TB at any given point of time in an average household of five, 40% of the non-infected population in a contact household are infected per year, incidence of disease among newly infected group is seven, times of the incidence among previously infected, incidence of disease in general population is 0.13% and from among previously infected persons 0.3% per year develop sputum disease.

At an incidence rate of 0.13% per year among general population aged >5 years, it is expected that 111 cases would arise in a year in the population of 1,00,000 under study. Thus, of the 111 cases occurring in the community, 101 arise from those who are not contacts.

The proportional contribution of new cases from the contact group to the total incidence cases in the entire community is so small, that even if all the contacts are kept under surveillance, BCG vaccinated or placed on chemoprophylaxis, still over 90% of incidence cases cannot be prevented from occurring. This is apart from the fact that keeping them under surveillance will be highly costly and is an operational problem of considerable magnitude.

KEY WORDS: INCIDENCE, CASE, CONTACTS, MODEL
 

 
  OPERATIONS RESEARCH  
 
B : Programme Development
 
103
SHORT COURSE CHEMOTHERAPY OF TUBERCULOSIS PROCEDURAL STRATEGIES IN DISTRICT TUBERCULOSIS-PROGRAMME
P Jagota: NTI Newsletter 1982, 19, 95-102.

In the wake of implementation of Short Course Chemotherapy (SCC) in the programme, some of the organizational aspects of SCC as observed in a clinical trial at the Lady Willingdon State TB Centre (LWSTC), Bangalore vis-a-vis to those recommended in the programme were evaluated. The efficacy of 3 SCC regimens of 3-5 months duration under clinical trial were studied among 381 patients. The efforts and the resources employed to achieve the results in the trial are compared with that of those recommended in the District TB Programme (DTP).

It is observed that there is a wide gap between the clinical trial and the programme in organisational efforts and resources. Although the trials cannot act as a model, if benefits associated with the SCC are to be availed, extra staff and transport for home visiting should be provided. The aspects of the organisation which need strengthening are motivation, timely defaulter action (preferably on the same day mainly as home visit) and efficient management of large number of patients attending the clinic for supervised drug administration, adverse reaction etc., before recommending the use of SCC in the DTP.

KEY WORDS: SCC, CONTROL PROGRAMME, CLINICAL TRIAL, RESOURCES.

108
A STUDY ON ADVERSE DRUG REACTIONS IN TWO REGIMENS OF SHORT COURSE CHEMOTHERAPY
Sudha Xirasagar, P Jagota, N Parimala & K Chaudhuri: NTI Newsletter 1989, 25, 51-60.

In a study of feasibility of treatment of smear positive patients with Short Course Chemotherapy (SCC) regimens under District TB Programme (DTP) conditions in a city, adverse drug reactions in terms of frequency of episodes, incidence in the cohort of patients, time of occurrence, major adverse reactions requiring modification of chemotherapy and or symptomatic treatment, were investigated.

Patients were allocated to one of the two 8 month SCC regimens i.e., Regimen 'A' 1 SHRZ/6TH, Regimen 'B' 2SHR/6TH. Overall incidence of adverse drug reaction in cohort of 265 patients was 37%, 9% of which were considered as major in nature. 34 episodes of such reactions resulted in modification of chemotherapy in 15 patients during intensive phase. Though gastro intestinal symptoms were predominant, cutaneous toxicity was the pre eminent cause of modification of regimen. No case of exfoliative dermatitis occurred. A total of 333 episodes of adverse drug reactions of minor nature occurred; 50% being gastro intestinal symptoms followed by cutaneous symptoms. More than 70% of all adverse drug reactions of intensive phase occurred in the first half of the period. There was no significant difference between the two regimens in the incidence of adverse drug reactions of either major or minor in nature.

SCC is being implemented in a phased manner in the DTP. Before introducing SCC in large number of districts, it would be prudent to find out whether SCC would be acceptable to both doctor and patient in terms of adverse drug reactions.
It can, therefore, be concluded that adverse reactions may not be a major constraint for inclusion of SCC under DTP for treating sputum positive tuberculosis patients provided that additional resources and man power are allocated to the DTCs to manage patients in the centre and extend effective guidance to staff working in peripheral centres.

KEY WORDS: SCC REGIMEN, DAILY REGIMEN, ADVERSE REACTIONS, CONTROL PROGRAMME, FEASIBILITY.

109
STUDY OF CAMPS FOR EXAMINING SPUTUM OF CHEST SYMPTOMATICS ATTENDING OUTPATIENTS OF PERIPHERAL HEALTH INSTITUTIONS
P Jagota, B Mahadev, BT Uke & KL Vasudeva Rao: Indian J TB 1989, 36, 27-30.

A study was designed to evaluate the outcome of holding sputum camps. The chest symptomatics referred by Peripheral Health Institutions (PHIs) to the camp were compared in terms of proportion of chest symptomatics registered and number of cases found with routine Case-finding actually carried out in the PHIs of an average District Tuberculosis Programme (DTP) and any educative effect of camp on the PHI staff. The study was carried out in 15 PHIs with wide range of performances in Case-finding. A team consisting of Medical Officer (MO), Treatment Organiser and Laboratory Technician of National TB Institute conducted sputum camps by involving the local staff and MOs of PHIs. The MOs of PHIs registered all the eligible symptomatics from the daily outpatients for a period of one month before the due date of the camp. The sputum was collected, slides prepared and patients advised to come on the camp date. A total of 528 chest symptomatics who reported at the PHIs during camp month were registered. Of them, 380 patients' sputum smears were prepared and 25 were found positive. Of the 528 symptomatics referred to the camp, only 86 (16.3%) actually turned up and 4 (16%) were positive. Prior to the sputum camp, 54 smear positive cases were diagnosed by these centres in 6 months. In the subsequent 6 months, 112 cases were diagnosed.

The study clearly shows that the efficacy of Case-finding by the sputum camp method is very low in comparison with integrated Case-finding at PHIs. More than 80% of the cases were missed by the camp by way of loss due to referral on the camp day. However, there was significant increase in the total number of cases diagnosed during 6 months after the camp, in comparison to 6 months prior to camp, thus, indicating the educative effect of the camp on the PHI MOs. The integrated sustained Case-finding activity in the PHIs cannot be substituted with the periodic Case-finding camps or holding of 'specialised clinics'.

KEY WORDS: CHEST SYMPTOMATICS, SPUTUM CAMP, PHIs, CASE-FINDING, REFERRAL.

110
A STUDY OF OPERATIONAL FACTORS INFLUENCING THE APPLICABILITY OF TWO REGIMENS OF SHORT COURSE CHEMOTHERAPY UNDER CONDITIONS OF AN URBAN TUBERCULOSIS PROGRAMME
P Jagota, Sudha Xirasagar, N Parimala & K Chaudhuri: Indian J TB 1989, 36, 213-23.

An operational study of two regimens of Short Course Chemotherapy (SCC) to assess their efficacy under programme conditions, applicability and feasibility in District TB Programme (DTP) was undertaken in an urban TB centre. The two regimens studied were 1SHRZ/7TH and 2SHR/6TH. Their operational efficacy (efficiency) was found to be 87% and 92% respectively which had already been reported in an earlier paper. The various factors i.e., initial willingness, drug default, treatment completion pattern, adverse drug reactions and initial drug resistance with their potential harmful effects on the treatment outcome as well as work load and extra cost these regimens entail for DTP organisation are discussed in this paper.

Out of a total of 1822 smear positive patients diagnosed at the Lady Willingdon State TB Centre during intake period (Feb '84 to March '85), 1126 were residents of Bangalore City. Of these 695 (61.7%) were unwilling to attend the clinic daily for 2 months, 27 were unfit and one was excluded by mistake. Thus, 403 (38.3%) initially willing patients were classified either as 'core group' or 'Non core group’, according to the history of previous anti TB treatment (321 and 82 respectively). Of the 695 (77.6%) unwilling persons, majority were those who pleaded inability to attend daily for 2 months without specifying any particular reason. Refusal of SCC due to injections accounted for 12.8% and 9.5% wanted to take treatment elsewhere. Old age influenced willingness adversely.

Of the 321 patients in the core group, 56 were excluded due to missing more than 50% of intensive phase doses. Among the remaining patients, 61 (48%) out of 127 patients on Regimen A and 48 (34%) out of 138 on Regimen B, did not make a single default in the intensive phase. Of the total 910 defaults for which actions were taken, 640 (70%) were retrieved by letter writing, among the remaining 293 (72%) were retrieved by home visiting. Main reasons for default elicited during home visits were: going out of station (52.9%) followed by patients being busy with work (19.1%). Compensatory phase was availed by 156 of the 265 patients who missed one or more doses due to default in the treatment. The pattern of treatment completion of 321 core group patients in the two regimens were similar i.e., in both the phases 65% for Regimen A and 63% for Regimen B. Incidence of minor adverse reactions was 28% and major toxic reactions were experienced by 8.4% of patients. Workload for treating 321 patients was due to supervised administration of drug 45 patients per day. Letter writing to 3.1 per patients, home visiting 1.1 per patient and doctor's attention for adverse reaction 2 occasions per patient. This could be managed with the existing staff. The cost of Regimen A was Rs.220/ per patient and for Regimen B, 268/ per patient. Cost to patient for transportation was Rs.70/ and Rs.113/ for Regimen A and B respectively.The major disturbing finding of the study was initial low acceptability of about 40% for SCC. The home visiting which was crucial in increasing the completion rate in this study is usually not available in most of the DTCs. Workload, adverse reactions etc. were not of any problem for implementation of SCC in the programme.

KEY WORDS: SCC, DAILY REGIMEN, OPERATIONAL FACTORS, APPLICABILITY, CONTROL PROGRAMME.

111
THE FATE OF RESISTANT CASES TREATED WITH THREE DIFFERENT DRUG REGIMENS OF SHORT COURSE CHEMOTHERAPY UNDER PROGRAMME CONDITIONS
P Jagota, TR Sreenivas, N Parimala & K Chaudhuri: Indian J TB 1990, 37, 83-87.

The fate of patients with isoniazid (H) resistant pulmonary tuberculosis, treated with 3 different Short Course Chemotherapy regimens (Regimen A-1 SHRZ/7TH, Regimen B-2SHR/6TH, Regimen C-2EHR/4H2R2) was examined in two sequential studies. One hundred H resistant patients belonging to two groups-one without history of previous treatment(core group) and second with history of previous treatment >=15 days (non-core group), were followed up at the end of 12th, 15th and 24th/36th month of chemotherapy. Bacteriological favourable response among patients in the core group at the end of chemotherapy with Regimen A, B and C were 65.2% of 23 patients, 50% of l8 patients, and 57.1% of 18 patients respectively. The response among patients in the non-core group were 27.3% with Regimen A and 52.6% with Regimen B.

At the end of 24/36th month of chemotherapy, 62.5% patients in the core group and 2 out of 7 in the non-core group on regimen A and 68.7% patients on regimen C in the core group and 5 out of 15 in the core group and 41.7% in the non-core group on regimen B were culture negative. The relapses were significantly high in regimen B & C in comparison with regimen A. Thus, of the total 100 patients, 99.3% were eligible for examination (1 died during chemotherapy), 67 were examined and of them 37 (62.7%) were culture negative, 22 positive and 8 were dead. The development of drug resistance to rifampicin was directly related to the duration of its use.

KEY WORDS: SCC, DRUG RESISTANCE, EFFICACY, CONTROL PROGRAMME, FATE.

114
INITIAL DRUG RESISTANCE TO ANTI TUBERCULOSIS DRUGS IN URBAN AND RURAL DISTRICT TUBERCULOSIS PROGRAMME
Sujatha Chandrasekaran, P Jagota, & K Chaudhuri: Indian J TB 1992, 39, 171-75.

The problem of drug resistance in tuberculosis is said to be on the increase in developing countries. This could adversely affect control measures. A knowledge of the prevalence and pattern of drug resistance would be of great help to the programme planners for purposes of monitoring and future planning. Hence, a survey on initial drug resistance to anti-TB drugs, as it occurs under programme conditions, was conducted in the urban situation of Bangalore and rural area of Kolar district. The proportion of Initial Drug Resistance (IDR) to anti tuberculosis drugs was estimated among new patients attending Bangalore (urban) and Kolar (rural) District Tuberculosis Programmes (DTPs). The sputum samples were collected from all newly diagnosed patients in this area and subjected for culture and drug sensitivity tests. It was observed that IDR to any drug was 34.9% (Isoniazid 32.87% and Rifampicin 4.4%) among Kolar patients. Among Bangalore patients, IDR was 20.57% (Isoniazid 17.35% and Rifampicin 2.89%). Combined resistance to isoniazid and rifampicin was 1.36% in urban DTC and 3.42% in rural DTP. With the introduction of Short Course Chemotherapy in DTP, combined resistance to isoniazid and rifampicin assumes paramount importance and needs to be monitored continuously.

KEY WORDS: INITIAL DRUG RESISTANCE.

115
RESULTS OF TREATMENT WITH A SHORT COURSE CHEMOTHERAPY REGIMEN USED UNDER FIELD CONDITIONS IN DISTRICT TUBERCULOSIS PROGRAMME
K Chaudhuri, P Jagota & N Parimala: Indian J TB 1993, 40, 83-89.

The treatment results of an unsupervised Short Course Chemotherapy (SCC) regimen used under conditions of District Tuberculosis Programme (DTP) are presented. The District Tuberculosis Centre (DTC), Kolar and six of its Peripheral Health Institutions (PHIs) formed the study area. No extra efforts except ensuring of adequate availability of drugs at the participating centres were made to obtain patients' compliance. In all, 584 smear positive tuberculosis patients were diagnosed during the study period but 28.3% of the patients could not be initiated on treatment with the chosen self administered SCC regimen -2EHRZ/6TH(EH).

Of the 382 put on treatment, only 33.2% completed over 75% drug collections in both intensive and continuation phases. The pattern of treatment compliance did not vary with the place of treatment, i.e. DTC or PHI. Irrespective of treatment compliance, nearly 72-77% of the patients attained smear negative status at the end of the period of treatment, there being no difference between PHI and DTC. However, deaths were higher in the PHI patients. This could be attributed to a significantly higher proportion of aged patients taking treatment at PHI than at DTC. Considering death as an unfavourable outcome, overall favourable response was 65.9%. Patients with drug sensitive bacilli had a higher rate of culture negativity (70%), as compared to those with drug resistant bacilli (48%). It was concluded that unsupervised SCC could give encouraging results in a DTP setting, provided adequate drug supply was ensured.

KEY WORDS: SCC, CONTROL PROGRAMME, OPERATIONAL EFFICACY.
 

 
  BACTERIOLOGY  
 
 
158
VALUE OF SPUTUM EXAMINATION IN PREDICTING PROGNOSIS DURING SHORT COURSE CHEMOTHERAPY
Sujatha Chandrasekaran, R Rajalakshmi & P Jagota: NTI Bulletin 1993, 29, 41-44.

Culture examination of sputum is known to be the best tool for assessing the prognosis of pulmonary tuberculosis patients. Controlled clinical trials with Short Course Chemotherapy (SCC) have shown that culture examination of sputum at the end of two months elicited a high degree of conversion, while smear results were inferior due to presence of dead organisms in the sputum. But, it is not possible to provide sputum culture facilities in the District TB Programme (DTP). Since smear examination facilities is widely available under the DTP, this paper examines the comparability of smear results with culture in patients treated with SCC. It also examines the value if any, of an early evaluation of the treatment outcome with SCC under operational conditions by doing smear examination at two months. Data from two operational studies on SCC are utilised for this purpose.

Of 256 total patients examined, 62 were smear positive at the end of two months, but 41 of them were excreting non- viable bacilli and were culture negative. Nevertheless, in predicting the final outcome of chemotherapy, no significant difference was observed between smear and culture examination at the end of two months. Smear positivity at the end of 2 months, by itself, cannot be considered to bode an unfavourable response, whereas negativity had a good probability of a favourable response. Microscopy in SCC gave as reliable a result as culture both during and at the end of chemotherapy. Hence, a properly conducted smear examination is as good as culture for diagnostic and prognostic purposes under operational conditions.

KEY WORDS: SMEAR EXAMINATION, SCC, PREDICTIVE VALUE, CONTROL PROGRAMME, FIELD CONDITIONS.
 

 
  ASSESSMENT & EVALUATION  
 
 
173
CASE HOLDING IN TUBERCULOSIS PROGRAMME EPIDEMIOLOGICAL PRIORITIES & OPERATIONAL ALTERNATIVES
P Jagota, AK Chakraborty & VH Balasangameshwara: NTI Bulletin 1993, 29, 1-9.

Potentials of Case-finding and case holding through operational studies conducted by National TB Institute (NTI) and elsewhere have been quantified. The potential of case holding is not satisfactory and needs revision of strategy to obtain better treatment completion. The present report reviews the programme in its ability to meet the potential in Case-finding and treatment (CFT), and bring about a reduction in the problem. Outcome at the current levels of efficiency of activities as well as following hypothetical changes in them, are studied. Further it identifies the areas for carrying out studies on structural changes to be introduced in the programme, so as to obtain higher results in terms of epidemiological gains.

A set of hypothesis which have been used in constructing the model are based on the currently available information on the epidemiology of tuberculosis and performance of the programme. An average Indian district as per 1991 census is considered to have: (a) a population of 1.9 million; (b) 6460 smear and culture positive patients (prevalence rate of 4 per thousand) in all at any time; (b1) 2584 of the prevalence cases are smear positive; (b2) 2196 newly occurring cases every year (annual incidence of 34% of prevalence); (b3) 879 of the b1 being the annual incidence of smear positive cases; (c) 3230 of the prevalence cases who present themselves for diagnosis (50% of b); (d) 2584 can be diagnosed if all the available PHIs participate in the programme as per the manual. This is called Case-finding potential (CFP). The Case-finding Efficiency (CFE) is expressed as a proportion of the cases being diagnosed out of the CFP by a DTP. The current CFE is calculated at 36% of CFP, as 936 cases are being diagnosed (as per the periodic DTP reports prepared by NTI). The result of treatment at the current treatment efficiency TE1 for the cases on Standard Regimen (SR) (Compliance 45% at level 4) is 50%, TE2 for those on SCC (compliance 56% at level 4) is 79%, TE3 WHO recommended 85% cure rate (compliance level and regimen not stated). DTP efficiency (DTPE) is the proportion of cases which could be cured with the respective TE, calculated out of the CFP. DTPE under SR l8%, under SCC is 28.44%.

Epidemiological impact is calculated while taking into consideration the natural dynamics of tuberculosis without intervention and the dynamics of the programme where the cases are diagnosed and treated with SR under the current efficiency, the same is computed for the patients treated with SCC with present level of efficiency. The cure and death rates among treated cases is added to the natural cure without a programme (Case fatality rate of 14% and cure rate of 20% is equal to 34% of incidence rate which keeps the prevalence rate unchanged in natural dynamics). With all the cases treated with SR, programme appears to show a problem reduction of 4.6% annually and with SCC of 6.5%. The latter shows a relative benefit of 41% over the former besides causing prevention of deaths at the end of treatment.

 Addl decline alternative in question
------------------------------------------------- X 100
               Relative Benefit

Decline with 36% CFE & on SR with 45% compliance level IV

Intervention alternatives with fixed CFE by raising compliance level 4 from 45% to two higher levels to 70% and 90%, are studied. They give an additional decline of 2.1% and 3.0% respectively. While raising compliance level 4 of patients on SCC from current 56% to 70% and 90%, the additional decline is marginal (2.6% & 2.9%). At the same time raising the compliance to the level 4 is not only operationally a difficult task but does not commensurate with epidemiological gains also.

Intervention Alternative Recommended by WHO : To further epidemiological gains, it is obvious that CFE also needs to be raised. The WHO has recommended the target of CFE as 70% of all smear positive cases, TE as 85%. For this alternative, DTPE is 59.5%; epidemiological gain 13.7%, additional decline 9.5% on SR with 45% compliance level and relative benefit of 206.5%. This alternative appears to be feasible provided coverage of implementation of PHIs and treatment compliance are high and use of SCC regimens in the programme are ensuring for such achievements.

Operational Alternatives on Improving Treatment Compliance To improve treatment compliance level it is essential that patients are treated free, get supply of drugs regularly as near to their homes as possible and may be given supervised treatment specially in the intensive phase. Recent development of infrastructure makes it possible to consider alternatives to ensure the supply of drugs close to patients residence. Some of the health functionaries below the level of PHIs are: Health Worker (HW) Anganwadi Worker, Dai (Traditional Birth Attender), Community Health Volunteers (CHV) and Private Practitioner. The possibility of involving them in some or other manner in tuberculosis treatment activity under a programme may be explored.

KEY WORDS: CASE-FINDING, CASE HOLDING, POTENTIAL, CONTROL PROGRAMME, EFFICIENCY, ALTERNATIVE.
 
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