Tuberculosis (TB)

Results: Detection and treatment of TB cases

Treatment results, 1994–2001 cohorts

Over 1.2 million new sputum smear-positive cases were registered for treatment in DOTS programmes in 2001, approximately the same number that were notified that year (Table 8 , Annex 3 lists notified and registered cases for 2001 by country). However, there were marked discrepancies between notifications and registrations (>10% of cases notified) in data submitted by South Africa, Thailand, Brazil, and Afghanistan.

Of the registered DOTS cases, only 2.2% were not evaluated for treatment outcome (Table 8). The cure rate among registered cases was 73%, and a further 9.2% completed treatment (no laboratory confirmation of cure), giving a reported, overall treatment success rate of 82% under DOTS. An estimated 26% of all smear-positive cases arising in 2001 were treated successfully by DOTS programmes.

By contrast with DOTS programmes, the quality of reporting and the outcomes of treatment were far worse in non-DOTS areas (Table 9). Only 5 HBCs reported treatment outcomes from non-DOTS areas. The discrepancies between cases notified and registered were significant for Brazil, China, and South Africa, but not for Bangladesh or India. The overall treatment success for these 5 countries was very low because outcomes were not evaluated for the majority of patients in India (61%). Among the cases that were registered for treatment, only 25% were cured and 40% were successfully treated. The death rate among evaluated patients was lower than in DOTS programmes (3%), but the proportion lost to follow-up was far higher (default plus transfer, 23%), and a proportion of these lost patients would have died.

By WHO region, the documented treatment success rates by DOTS programmes varied from 71% in Africa to 93% in the Western Pacific Region (Figure 14a, Table 8). Fatal outcomes were most common in Africa (7%), where a higher fraction of cases are HIV-positive, and Europe (6%), where a higher fraction of cases are drug resistant (eastern Europe), or occur among the elderly (western Europe). Treatment interruption (default) was most frequent in the African (10%), Eastern Mediterranean (7%), and South-East Asia Regions (7%). Transfer without follow-up was also especially high in Africa (7%). Treatment failure was conspicuously high in the European Region (8%), mainly because a high proportion of patients in eastern Europe are recorded as failures (11%).

DOTS treatment success was 80% or more in 11 HBCs, and exceeded the 85% target in 6 of these countries (Table 8). It was under 70% in South Africa, the Russian Federation, Brazil, and Uganda. In South Africa, 24% of patients defaulted from treatment, or were transferred without follow-up. In Russia, 14% failed treatment. In Brazil and Uganda, the treatment results for 15% of patients were not evaluated in any way. An additional 17% defaulted from treatment in Uganda, which reported the lowest proportion of successful treatments among the 22 HBCs (56%).

Figure 14: Outcomes for those patients not successfully treated in (a) DOTS and (b) non-DOTS areas, by WHO region, 2001 cohort. The true outcome of treatment is unknown for a high proportion of patients in non-DOTS areas.

A comparison of treatment results for 8 consecutive cohorts (1994--2001) shows that the overall success rates have been above 80% under DOTS since 1998 (Table 10). Treatment success rates were worse outside DOTS programmes in all regions, principally because large fractions of cases were not evaluated (Figure 14 b).

In DOTS areas, over 186 000 cases were registered for retreatment in 2001 (Table 11). Some patients remain on treatment (included with those "not evaluated"), but the latest data give an overall treatment success rate of 73%. More failures and deaths are expected among patients being treated on a second or subsequent occasion, but the success rate is low in this cohort, as in the year 2000 cohort, mainly because of the high default rate.


Related links