Elsevier

The Lancet

Volume 364, Issue 9432, 31 July–6 August 2004, Pages 417-422
The Lancet

Articles
The effect of tuberculosis control in China

https://doi.org/10.1016/S0140-6736(04)16764-0Get rights and content

Summary

Background

China has 1·4 million new cases of tuberculosis every year, more than any country except India. A new tuberculosis control project based on short-course chemotherapy was introduced in half the country in 1991, after a national survey of tuberculosis prevalence in 1990. Another survey was done in 2000 to re-evaluate the national tuberculosis burden, providing the opportunity to assess the effect of the control project.

Methods

The survey in 2000 identified 375 599 eligible individuals at 257 investigation points chosen from all 31 mainland provinces by stratified random sampling. Children (aged 0–14 years) were suspected of having tuberculosis if they had an induration of 10 mm or greater after a tuberculin skin test, and an abnormal fluorograph. Adults were suspected if they had a persistent cough, abnormal fluorograph, or both. Tuberculosis was diagnosed by chest radiograph, sputum-smear microscopy, and culture.

Findings

365 097 people were examined (97% of those eligible). Prevalences of pulmonary, culture-positive, and smear-positive tuberculosis in 2000 were 367 (95% CI 340–397), 160 (144–177), and 122 (110–137) per 100 000 population, respectively. Between 1990 and 2000, prevalences of these three forms of the disease had fallen, respectively, by 32% (5–68), 37% (7–66), and 32% (9–51) more in areas in which the project was implemented than in non-project areas. For culture-positive disease, a 30% (9–48) reduction was directly attributable to the project.

Interpretation

Between 1991 and 2000, prevalence of tuberculosis was reduced significantly in areas of China by use of short-course chemotherapy following WHO guidelines. We estimate that in 2000, in a population of more than half a billion, there were 382 000 fewer prevalent culture-positive cases and 280 000 fewer prevalent smear-positive cases than there would otherwise have been.

Introduction

China had an estimated 1·4 million new cases of tuberculosis in 2000—more cases than any country except India.1 The precise burden of the disease is, however, uncertain because case notifications are incomplete and because, until 2000, no survey had been undertaken since a control project, funded in part by the World Bank, was implemented in half the country from 1991 onwards.

The new project followed the internationally-recommended DOTS strategy, which has five components: political commitment; case detection by sputum smear microscopy, mostly among self-referring symptomatic patients; standard short-course chemotherapy administered under proper case-management conditions, including directly observed therapy; a system to ensure regular drug supplies; and a standard recording and reporting system, including the assessment of treatment outcomes.2 This strategy was implemented in 13 of 31 mainland provinces, municipalities, and autonomous regions, inhabited by more than 560 million people.3 The goal of the project is the same as that for DOTS projects elsewhere: to detect 70% of new smear-positive cases arising each year, and to cure 85% of these cases, by 2005.2 By reaching this goal, China could expect to reduce the prevalence of tuberculosis by 50% before 2015, at least in the part of the country covered by the new project. These achievements would be consistent with targets for tuberculosis control included among the UN Millennium Development Goals.4, 5

By the end of 2000, 1132 of 1208 counties in the 13 areas (provinces, municipalities, and autonomous regions) had been using DOTS for at least 5 years, and the median duration of project implementation in all counties was 7·25 years. A standard, free diagnostic assessment is provided for all people with symptoms of tuberculosis through a network of dispensaries, and treatment is free for patients with sputum smear-positive disease.3 Nearly 8 million individuals with suspected tuberculosis were examined in dispensaries between 1991 and the end of 2000. Early results of the project showed a cure rate of 90% among new smear-positive cases, and this achievement has been maintained with a growing number of patients through the 1990s.3, 6 The DOTS programme recorded a total of 149 429 new smear-positive patients treated in 2000 with a reported cure rate of 96·7%, consistent with earlier years.7

To re-evaluate the national tuberculosis burden, a comprehensive, national tuberculosis disease prevalence survey was done in 2000, following earlier surveys in 1979 and 1990.8 We report the principal findings of the latest survey, and compare results with those from the 1990 survey. Because tuberculosis has been in long-term decline in China, as in other parts of the world,9 we assess the effect of the new project by comparing changes in prevalence in project and non-project areas of the country, after nearly a decade of project implementation.

Section snippets

Survey design

The survey was designed to detect a change of 20% in national prevalence of smear-positive tuberculosis between 1990 and 2000 with a probability of greater than 95% and power 95%, allowing for 90% participation in 2000. The 257 investigation points were selected randomly from within the 31 mainland provinces, municipalities, and autonomous regions (henceforth termed “provinces”), but allocated among these areas by population size. Surveyors attempted to examine all eligible children and

Results

Of 375 599 individuals eligible in 2000, 365 097 (97%) were actually examined, a higher proportion than anticipated in the survey design. Of 4667 people with abnormal fluorographs, 4558 provided three sputum specimens. There were 1340 cases of active pulmonary tuberculosis (367 per 100 000; 95% CI 340–397), 584 of which were confirmed by culture (160 per 100 000; 144–177), and 447 were sputum smear-positive (122 per 100 000; 110–137). These values correspond to a total of 4·7 million (95% CI

Discussion

China's enhanced tuberculosis control project, funded in part by a loan from the World Bank, was not a formal experiment, but has provided an opportunity to evaluate the effect of tuberculosis control on a large scale. Despite the limitations of the design, we showed that in the project areas the prevalence of disease fell by about 30% after 7 years, compared with an insignificant change in non-project areas. We estimate that in 2000, the project area had 836 000 fewer cases of pulmonary

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