Low tuberculosis notification in mountainous Vietnam is not due to low case detection: a cross-sectional survey.

BACKGROUND: Studies show that tuberculosis notification declines with increasing altitude. This can be due to declining incidence or declining case detection. In Vietnam notification rates of new smear-positive tuberculosis in the central mountainous provinces (26/100,000 population) are considerably lower than in Vietnam in general (69/100,000 population). In order to clarify whether this is explained by low incidence or low case detection, we aimed to assess the prevalence of new smear-positive tuberculosis among adults with prolonged cough in three mountainous provinces in central Vietnam. METHODS: A house-to-house survey of persons (> or = 15 years) was carried out in twelve randomly selected districts in 2003. Three sputum specimens were microscopically examined of persons reporting a prolonged cough (> or = 3 weeks). Case detection was assessed by the ratio between notification and prevalence. RESULTS: Of 68,946 included persons (95% response), 1,298 (1.9% 95%CI 1.8-2.2) reported a prolonged cough. Of these, eighteen were sputum smear-positive of whom two had had anti-tuberculosis treatment. The prevalence of new smear-positive tuberculosis was 27/100,000 (95%CI 11-44/100,000) and the notification rate was 44/100,000 among persons > or = 15 years. The estimated case detection rate was 76%. CONCLUSION: Low tuberculosis notification in this mountainous setting is probably a true reflection of low tuberculosis incidence. Possible causes for low incidence in mountainous areas include low transmission rates or altitude-related differences in pathology.

Steep increases in tuberculosis notification among young men in the industrialised districts of Danang, Vietnam.

BACKGROUND: Tuberculosis (TB) notification is increasing among young adults in urban provinces in Vietnam, despite having achieved World Health Organization targets for treatment success and case detection. OBJECTIVES: To identify causes for non-declining TB case rates in an urban area of Vietnam, and to describe trends in new smear-positive pulmonary TB notification by age, sex and district in the period 1999-2004 in Danang City, Vietnam. RESULTS: Age and sex-standardised notification rates declined by 1.3% (95%CI -2.3-0.3%) annually. Notification rates among men aged 15-44 in Danang City increased significantly (5%, 95%CI 2.4-7.7 annually), most notably in industrialised districts (>or=12% annually). CONCLUSION: TB notification rates among young men in an urban setting in Vietnam increased most notably in industrialised districts. We hypothesise that this is due to poor living and working conditions and internal migration rather than to an emerging human immunodeficiency virus epidemic.

Survival and relapse rate of tuberculosis patients who successfully completed treatment in Vietnam.

SETTING: Reported tuberculosis (TB) cure rates are high in Vietnam with the 8-month short-course chemotherapy regimen. However, long-term treatment outcomes are unknown. OBJECTIVE: To assess survival and relapse rates among patients successfully treated for new smear-positive pulmonary tuberculosis (PTB). METHODS: A cohort of patients treated in 32 randomly selected districts in northern Vietnam were followed up 12-24 months after reported cure or treatment success for survival and bacteriologically confirmed relapse. Measurements included sputum smear examination, culture and interview for recent treatment history. RESULTS: Of 304 patients included in the study, no information was available for 31 (10%) and 19 (6%) had died. Bacteriology results were available for 244 (80%). The median interval between treatment completion and follow-up was 19 months. Relapse was recorded in 21/244 (8.6%, 95%CI 5.4-13), including 9 (4%) with positive sputum smears, 3 (1%) with negative smears but positive culture and 9 (4%) who had started TB retreatment. Four of 12 culture-positive relapse cases (33%) had multidrug-resistant strains. If the definition of relapse was extended to include death, reportedly due to TB, the relapse proportion was 26/263 (9.9%, 95%CI 6.6-14). CONCLUSION: A substantial proportion of patients (15%) had died or relapsed after being successfully treated for TB in northern Vietnam.

Tuberculosis epidemiology in six provinces of Vietnam after the introduction of the DOTS strategy.

SETTING: Six provinces in Vietnam where the DOTS strategy was introduced in 1989. OBJECTIVE: To assess the impact of improved tuberculosis (TB) control on TB epidemiology in Vietnam. METHODS: Data from the surveillance system in the period 1990-2003 were analysed to assess trends of notification rates and the mean ages of notified cases. Data from repeated tuberculin surveys in the period 1986-2002 were estimated to assess the prevalence of TB infection, the annual risk of infection and its trend using various cut-off points in those with and without bacille Calmette-Guérin (BCG) scar. RESULTS: Age-standardised notification rates in the period 1996-2003 declined significantly, by 2.6% to 5.9% per year, in five provinces. However, in four provinces notification rates in the age group 15-24 years increased significantly, by 4.5% to 13.6% per year, during this period. The mean age of newly diagnosed patients with smear-positive TB increased up to 1995 but decreased thereafter. The annual risk of TB infection showed a significant annual decrease (4.9% per year) in one province in surveys performed between 1986 and 1997, and in two provinces (6.6% and 4.7%) in surveys conducted between 1993 and 2002. CONCLUSION: These data suggest limited impact to date of the DOTS strategy in Vietnam.

Evaluation of sputum smear microscopy in the National Tuberculosis Control Programme in the north of Vietnam.

OBJECTIVE: To assess the yield of sputum smear microscopy and sex differences in the National Tuberculosis Control Programme in the north of Vietnam. METHODS: Review of registers of 30 randomly selected laboratories (26 district, 4 provincial level). RESULTS: The average daily workload per technician was 4.4 examinations in district and 5.3 examinations in provincial laboratories. To find one smear-positive case, 9.7 suspects were examined and 29.3 smears done. The smear-positive rate (mean 10.3%) was higher among men (11.6%) than among women (8.4%, P < 0.001). There were more men than women among tuberculosis (TB) suspects (male:female ratio 1.36, 95%CI 1.19-1.54), but even more so among smear-positive patients (1.89, 95%CI 1.64-2.14), irrespective of specimen quality and number of smears examined. Three smears were examined for 18,055 suspects (61.7%). The incremental gain was 33.5% and 4.9% for the second and third smear examination, respectively; 186 (95%CI 160-221) smears needed to be examined to find one additional case of TB with a third serial examination. CONCLUSION: The diagnostic process seemed generally efficient. The male:female ratios suggest higher TB incidence in men rather than lower access to TB facilities for women. The third smear examination could be omitted.

Establishment and development of the National Tuberculosis Control Programme in Vietnam.

OBJECTIVE: To describe the establishment and development of the National Tuberculosis Control Programme (NTP) of Vietnam. METHODS: Data were obtained from the surveillance system established by the new NTP in 1986 and based on the principles now described as the WHO DOTS strategy. RESULTS: The proportion of districts covered by the NTP increased from 40% in 1986 to almost 100% in 2000. The proportion of communes applying NTP guidelines increased from 18% in 1986 to 99.8% in 2000. The total number of tuberculosis cases notified increased from 8737 in 1986 to 89 792 in 2000. Most of these are new smear-positive cases. Based on WHO estimations of the incidence rate, the proportion of new smear-positive cases detected and put on short-course treatment has been over 70% since 1996. Reported cure rates with short-course chemotherapy are consistently over 85%. CONCLUSIONS: DOTS is feasible in a low-income, high-burden country. The main reasons for success were political commitment, a well-functioning health network, integration of tuberculosis control into the general health service at district level, a continuous supply of drugs and effective external support. Major challenges are long-term financial support, expansion to remote areas and vulnerable groups, definition of the role of the private sector, and future developments of the HIV epidemic and multidrug resistance.

Knowledge about tuberculosis and its treatment among new pulmonary TB patients in the north and central regions of Vietnam.

SETTING: Tuberculosis (TB) units in 42 districts in north and central Vietnam were included in the study. OBJECTIVES: To describe patients' knowledge of TB and to evaluate the impact of the National Tuberculosis Programme's health education. DESIGN: New pulmonary TB patients who had received TB treatment for a minimum of 1 month were interviewed using a structured questionnaire. RESULTS: A total of 364 patients were interviewed; 93% of respondents reported receiving TB information from the health staff. Apart from health education, many patients reported TB information from the TV. This was more common among men than women (71.4% vs. 51.3%). The average knowledge score was 7.07 +/- 2.02 (maxium 10). This was significantly associated with level of education and receiving health education. More than half of the patients expressed fear of being known as TB patients in the community. CONCLUSIONS: Knowledge about TB and its treatment was generally high. Marginalised groups with limited access to media and low education levels may benefit from specially targeted educational interventions. To reduce stigma and the impact of social consequences of TB, an ongoing health education programme designed to increase the knowledge level in the whole population appears warranted.

Drug resistance among failure and relapse cases of tuberculosis: is the standard re-treatment regimen adequate?

OBJECTIVE: To determine acquired drug resistance among failure and relapse cases after treatment of new smear-positive tuberculosis. METHODS: A cohort of 2901 patients with new smear-positive tuberculosis was enrolled in Vietnam. Sputum samples were stored at enrolment. Upon failure or relapse, another sputum sample was collected. Both were cultured and underwent drug susceptibility testing and restriction fragment length polymorphism (RFLP) typing. RESULTS: Of 40 failure cases, 17 had multidrug resistance (MDR) at enrolment. At failure, 15 of the 23 (65%) patients without primary MDR had acquired MDR. Of 39 relapse cases and 143 controls, none had primary MDR. CONCLUSION: Primary drug resistance was a strong risk factor for failure and relapse and for acquiring further resistance. As 80% of failure cases had MDR, the standard re-treatment regimen appears inadequate for failure cases in this control programme with a very high cure rate among new cases.