TB in South-East Asia

DOTS Achievements in South-East Asia

      DOTS coverage

      Case detection and case notification rates

      Treatment success and cure rates

      Overall progress towards 2005 targets

DOTS coverage

DOTS coverage is defined as the population living in administrative areas where DOTS services are available. This indicator serves as a proxy for people with access to DOTS. Population access to DOTS increased from 77% at the end of 2003 to over 90% by mid 2005. Bhutan, Maldives and Thailand had already reached nationwide coverage by or before 2002.  DPR Korea and Myanmar followed in 2003. Sri Lanka and Timor-Leste have also significantly increased coverage. In India, the Revised National Tuberculosis Control Programme (RNTCP) extended DOTS coverage to over one-billion of India’s population in March 2005.

The figure below shows the DOTS case-detection rate among new smear-positive cases in the Region in relation to the population covered. There has been a significant increase in case detection over the years, moving steadily towards the 70% case-detection target as coverage has expanded.

Case detection and case notification rates

The South-East Asia Region accounts for 35% of all notified tuberculosis (TB) cases and a similar proportion of new smear-positive cases globally. In DOTS areas, 49% of all new and relapse cases are smear-positives. This is much more than in non-DOTS areas (29%) and is explained by the greater emphasis on smear microscopy under the DOTS strategy.

Trends in case detection under DOTS have also shown a steady increase and are greatly influenced by the detection rates in the high burden countries, and in particular, India. The Revised National Tuberculosis Control Programme of India has now covered over one billion people, and is expanding rapidly to cover the remaining population. It is expected that once data for 2005 is available, substantial increments in cases detected and notified will be seen, leading the Region as a whole to achieving or being well within reach of the 70% case-detection target set for end 2005.

In 2004, based on the current estimates for new smear positive cases, the case-detection rate was 57% for new smear-positive cases under DOTS and 59% counting DOTS and non-DOTS notifications together. For all TB cases, the case-detection rates were 52% and 55% respectively. It must be recognized however, that trends in case-detection rates are affected by both notifications (numerator) and changes in the estimated incidence (denominator). Some Member countries have already begun or have planned to undertake disease prevalence or ARTI surveys in order to obtain better estimates.

In 2004, the eleven Member countries in the South-East Asia Region (SEA Region) together notified 1 841 968 tuberculosis cases (all types) which represents 114 per 100 000 population. Of those, 779 159 or 49 per 100 000 were new smear-positive pulmonary cases. The table below shows the case notifications by category in Member countries.

Table: TB notifications in the SEA Region Member countries, 2004

Five countries in the Region – Bangladesh, India, Indonesia, Myanmar and Thailand which belong to the global list of 22 countries with the highest burdens of TB (HBCs) notified 1 743 622 cases, or 95% of all cases notified in the Region.

The increase in notifications of new-smear positive cases is much sharper, than overall notifications. This most probably reflects the greater emphasis on sputum smear microscopy in more recent years, resulting in cases previously classified as smear negative now being correctly identified and classified as smear positive.

New smear-positive cases

Among the 779 159 new smear-positive cases in the Region, India notified 489 031 cases (63%), Indonesia 128 981 (17%), Bangladesh 62 500 (8%), Myanmar 31 408 (4%) and Thailand 28 421 (3.6%), while the remaining six countries notified 38 818 new smear-positive cases or 5% of the Regional burden.

Positivity rate

The proportion of new smear-positive cases out of all new cases notified was 48% for the Region. Four countries, namely Bangladesh, Indonesia, Sri Lanka and Thailand, notified positivity rates higher than 50%. The positivity rate in DOTS areas is much higher than in non-DOTS areas. Cases registered in non-DOTS areas have been reported only by India and Sri Lanka.

Pulmonary smear-negative and extrapulmonary cases

The new smear-negative pulmonary and extrapulmonary cases represented 38% and 13%, respectively, of the notified new cases (table 1).

Relapse and Retreatment cases

All countries reported relapse cases. The other categories of retreatment namely treatment after failure, treatment after default and other retreatment cases, were reported by all countries excepting Bangladesh, Indonesia, Maldives and Thailand.

The proportion of retreatment cases represents 13% of all notified cases. However, the true percentage could be slightly higher, given underreporting by some countries.

While most cases are, not surprisingly, found in the most populous countries, the case-notification rates (number of new smear-positive cases per 100 000 population) show a wide range, between 16 and 108/100 000. Five countries have case notification rates (all cases of TB) of more than 100 per 100 000. Those countries are, in descending order: Timor-Leste, DPR Korea, Myanmar, Nepal and India.

Treatment success and cure rates

The overall cure rate in the Region for new smear-positive cases was 82% and the completion rate 3.3%, for the 598 293 cases registered in 2003. Thus the treatment success rate of 85.3%, is slightly above the global target of 85%. Seven countries have reached or exceeded the global target of 85% treatment success.

Reported mortality is as low as 5%. Failure rates are 2%, default rates 6% and the percentage of cases not evaluated (including transfers out) 2%. TB mortality is highest in Thailand (10%), mainly due to HIV, but also due to the relatively higher numbers of patients in the older age groups.

Regional figures are greatly influenced by the outcomes of programme implementation in the five high burden countries, and in particular, India, where the programme has now covered over one billion people, and is expanding rapidly to cover the remaining part of the population. This will result in a substantial increases in cases detected and notified.

Overall progress towards 2005 targets

With further improvements in both case-detection and treatment success in almost all countries in the Region compared to previous years, (see country profiles) the Region as a whole is showing steady progress towards reaching the set 70% and 85% targets as shown in the figure.

Trends in case-detection and treatment success rates