Estimation of burden of tuberculosis in India for the year 2000

Data on the burden of tuberculosis (TB) in India are vital for programme planners to plan the resource requirements and for monitoring the nation-wide TB control programme. There was a need to revise the earlier estimate on the burden of TB in India based on the increase in population and current epidemiological data. This study estimates the burden of disease for the year 2000 based on recent prevalence of TB and annual risk of tuberculosis infection (ARTI) estimates.

Data on prevalence generated among adults by the Tuberculosis Research Centre (TRC), Chennai, among children by National Tuberculosis Institute (NTI), Bangalore, and the ARTI estimates from the nation-wide sample survey by NTI and TRC were used for the estimation. The prevalence of disease corresponding to 1 per cent ARTI was extrapolated to different parts of the country using the estimates of ARTI and the population in those areas and added together to get the total cases. Abacillary cases that required treatment were estimated from X-ray abnormals. The estimates of bacillary, abacillary and extrapulmonary cases were then combined to get the national burden.

The estimated number of bacillary cases was 3.8 million (95% CI: 2.8-4.7). The number of abacillary cases was estimated to be 3.9 million and that for extrapulmonary cases was 0.8 million giving a total burden of 8.5 million (95% CI: 6.3-10.4) for 2000.

The present estimate differs from the earlier estimates because we have included the disease burden of X-ray cases that are likely to breakdown to bacillary cases in a one year period, and extrapulmonary TB cases. The current estimates provided baseline information for advocacy and planning resource allocation for TB control activities. Also, these estimates can be compared with that in future years to measure the long term impact of TB control activities in India.