Evaluation of different types of chest symptoms for diagnosing pulmonary tuberculosis cases in community surveys

Background: Prevalence of tuberculosis (TB) is an important epidemiological index to measure the load of the disease in a community. A series of disease surveys were undertaken in rural community in Tiruvallur district in Tamilnadu, south India Objective: To investigate the yield of pulmonary tuberculosis (TB) cases by different symptoms status and suggest predominant symptoms for detection of cases in the community based surveys. Methods: Three disease surveys were conducted during 1999-2006, in a random sample of 82,000 adults aged > 15 years to estimate the prevalence and incidence of pulmonary TB. All subjects were screened for chest symptoms and chest radiography. Sputum examination was done among those who were either symptomatic or abnormal on X-ray or both. Cases observed through symptom inquiry were included for analysis. Results: In survey-I, 65.6% had cough of > 14 days and yielded 79.1% of the total cases. In surveys II and III, symptomatic subjects with cough contributed 69.5% and 69.2% of the cases respectively. In survey I, 26.8% had symptoms without cough but with at least chest pain > 1 month contributed 8.4% of total cases. The corresponding proportions in subsequent surveys were 29.3, 11.5%; and 23.4, 11.2% respectively. The number of symptomatics without cough and chest pain but with fever > 1 month was negligible. Conclusion: The relative importance of cough as a predominant symptom was reiterated. The yield of pulmonary TB cases from symptomatics having fever of > 1 month was negligible. Fever may be excluded from the definition of symptomatics for screening the population in community survey

Weight gain in patients with tuberculosis treated under directly observed treatment short-course (DOTS)

Set up: One Tuberculosis Unit (TU) in Tiruvallur district, Tamil Nadu, India where Tuberculosis (TB) patients treated under Directly Observed Treatment Short Course (DOTS) programme. Objective: To identify the effects of weight gain among TB patients at the end of treatment on different factors such as socio-economic and demographic characteristics, smoking and drinking habits, treatment under supervision, the type of DOTS centres and problems in taking drugs. Methods: TB patients registered between May 1999 and December 2004 formed the study population. Multiple regression method was used for the analysis. Results: Among 1557 smear-positive TB patients registered under DOTS programme, the changes in weight ranged from a loss of 4 kgs to a gain of 20 kgs at the end of TB treatment; the average change in weight was 3.22 kgs. The gain in weight at the end of treatment was associated with age (<45 years), DOT at government centres, no problems in taking drugs as reported by patients and cure rate. Conclusion: The findings showed that there is an association between gain in weight with DOT at government centres and cure of patients

Survival of tuberculosis patients treated under DOTS in a rural tuberculosis unit (TU), south India.

Objective: To estimate survival probabilities and identify risk factors for death of tuberculosis (TB) patients during treatment period. Methods: TB patients registered during May 1999 to December 2004 from a rural TB unit (TU) with a population of 580 000 in Tiruvallur district, South India, formed study population. Life table and Cox’s regression methods were used. Results: Of the 3818 TB patients who were initiated on treatment, 96, 94 and 97% of category – I, II and III respectively, were surviving after completion of treatment. Higher death rates were independently associated with patient’s age (45 years), previous history of treatment, alcoholism and initial body weight (<35 kgs). Conclusion: The survival probability was found to be similar in all patients irrespective of categorization. Necessary actions need to be initiated in the programme to improve body weight and abstain from alcoholism

Quality of symptom elicitation in an epidemiological survey on tuberculosis

The quality of symptom elicited by health workers in an epidemiological survey on tuberculosis was assessed by again subjecting a 10% random sample of the persons interviewed, by the supervisory staff, independently. Three thousand four hundred and forty nine persons were thus interviewed twice. The overall estimates for overdiagnosis and under-diagnosis in the elicitation of symptoms by health workers were to the extent of 16% and 8% respectively, with minimal yield of sputum positivity from the discordant groups of persons. The additional load of 16% for sputum examination can thus be considerably reduced if health workers are well trained in symptom-elicitationscreening of the population and their work is monitored through spot supervisory checks

Failure to initiate treatment for tuberculosis patients diagnosed in a community survey and at health facilities under a DOTS programme in a district of south India

We studied the proportion and fate of tuberculosis patients who were not initiated on treatment (initial defaulters) in Tiruvallur district of Tamilnadu, where DOTS strategy was implemented. These patients were visited to find out the reason for default. Treatment was not initiated in 57 (23.5%) of the 243 sputum positive cases diagnosed in a community survey and 156 (14.9%) of 1049 patients diagnosed in health facility. Men were more likely not to have treatment initiated. The common reasons stated for initial default were unwillingness, symptoms being mild, personal reasons and dissatisfaction. There is an urgent need to improve the patient’s perception of treatment and strengthen the health systems’ capabilities to reduce initial default

Comparison of Tuberculin Reaction Sizes at 48 and 72 hours among children in Tiruvallur District, South India

Setting: A rural population in Tiruvallur district, south India. Objective: To study the variability of skin test reaction sizes between 48 and 72 hours. Methods: A tuberculin test survey was conducted among children aged less than 10 years. The reaction sizes were read by the same reader at 48 hours and 72 hours independently. The results of the tuberculin test were compared. Results: Of 957 children aged below 10 years were included in the study; the male and female ratio was 1:1.1. There were no significant differences between the readings of reaction size at 48 and 72 hours. Conclusion: The tuberculin test results can be read either at 48 hours or 72 hours without compromising the validity

Impact of BCG vaccination on tuberculin surveys to estimate the annual risk of tuberculosis infection in south India

Background & objectives: Annual risk of tuberculosis infection (ARTI) computed from prevalence of infection measures the extent of tuberculosis transmission in the community and it is used to monitor the tuberculosis control programme. This is usually derived from tuberculin surveys among children not vaccinated with BCG. This study explores whether the estimated ARTI among BCG vaccinated children is comparable to that of unvaccinated children. Methods: Three tuberculin surveys were undertaken among children aged <10 yr as part of assessing the impact of DOTS implemented in Tiruvallur district, south India. The prevalence of infection was estimated using the anti-mode method among vaccinated and unvaccinated children. The ARTI was computed separately and compared in all the three surveys. Results: The prevalence of infection among unvaccinated and vaccinated children in the first survey were 7.8 per cent (95% CI: 7.1-8.6) and 7.9 per cent (95% CI: 7.1-8.8) respectively (ARTI was estimated to be 1.6 per cent in both groups) and the difference was not statistically significant. The corresponding figures for children test read in the second and third surveys were 6.9 per cent (95% CI: 6.2-7.6) and 6.8 per cent (6.0-7.5) and; 6.0 per cent (5.2-6.7) and 6.0 per cent (5.5-6.5) respectively. The computed ARTI was respectively 1.4 and 1.2 per cent among unvaccinated children in the second and third surveys; and 1.4 and 1.2 per cent among vaccinated children in the second and third rounds. Interpretation & conclusion: There was no difference in the infection with Mycobacterium tuberculosis among vaccinated and unvaccinated children. BCG vaccinated children may thus be included for estimation of infection to assess the extent of transmission in the community as well as for monitoring purpose

Risk Factors for Non-adherence to Directly Observed Treatment (DOT) in a Rural Tuberculosis Unit, South India

Objective: To identify risk factors for non-adherence of tuberculosis (TB) patients to DOT. Methods: Retrospective study of TB patients by logistic regression analysis to identify risk factors for non-adherence. Results: Of the 1666 patients interviewed, 1108 (67%) adhered and 558 (33%) did not adhere to DOT. Of 558 patients, the risk factors associated with non-adherence were illiteracy (39%), difficulty in accessing health facility (57%), and nongovernment DOT centre (43%). Conclusion: Patients should be educated about tuberculosis and importance of DOT. All DOT centres, including Nongovernment DOT centres, should be made more accessible and patient-friendly

Impact of improved treatment success on the prevalence of TB in a rural community based on active surveillance.

Objective: To study the impact of improved treatment outcome of a cohort of patients treated under DOTS strategy on the prevalence of pulmonary tuberculosis (TB) in the community. Design: The data from TB register of one Tuberculosis Unit (TU) in Tiruvallur district of Tamilnadu, and two TB disease surveys conducted in the same area during 1999-2003 were analysed. The successful treatment outcome was compared to the prevalence of TB in the subsequent cohort. Results: The proportion of patients who completed treatment successfully was 75.3% in the first cohort period. This higher proportion of treatment success among patients treated under DOTS in the first cohort period (1999-2001) compared to the 51-55% reported during SCC, resulted in a lower prevalence of smear-positive cases, irrespective of culture results observed in the survey conducted during 2001-2003 compared to that in the survey conducted during 1999-2001 (252 vs. 323 per 100,000; annual decline of 9%). Similarly, a decline in culture-positive cases, irrespective of smear results, was also observed (443 vs. 605; annual decline 11%). Conclusion: The higher proportion of successful completion of treatment after DOTS implementation was associated with a substantial decline in the prevalence of TB. These findings showed that we are in the direction towards achieving the Millennium Development Goals (MDGs)

A novel method of staining acid-fast bacilli in sputum containers

Background & objectives: Making centrifuged deposit smears from sputum to detect acid-fast bacilli (AFB) is considered hazardous. We carried out this study to stain the centrifuged deposits with carbol-fuchsin in sputum containers and to decolourize and counterstain their smears made on glass slides. Methods: The centrifuged deposits of 180 sputum samples from pulmonary tuberculosis patients were used for making smears (initial deposit smears) and staining by Ziehl-Neelsen (ZN) method for the detection of AFB. Each of the sputum deposit was then treated with one ml of 1 per cent carbol-fuchsin and a smear made between 2 to 3 h was then decolourized and counterstained by the same procedures followed in ZN method (2 h stained deposit smear). The coded initial deposit smears and the corresponding 2 h stained deposit smears were read by the same readers and the results compared. Results: One hundred and fifty (70 positive and 80 negative) 2 h stained deposit smears were compared with initial deposit smears and the difference was not statistically significant. Interpretation & conclusion: Centrifuged deposits of sputum in sputum containers can be stained by carbol-fuchsin within 2-3 h and their smears made subsequently on glass slides can then be decolourized and counterstained by the procedures followed in ZN method for detection of AFB by light microscopy