The fourth national anti-tuberculosis drug resistance survey in Viet Nam.

SETTING: Viet Nam's Fourth National Anti-Tuberculosis Drug Resistance Survey was conducted in 2011. OBJECTIVE: To determine the prevalence of resistance to the four main first-line anti-tuberculosis drugs in Viet Nam. METHODS: Eighty clusters were selected using a probability proportion to size approach. Drug susceptibility testing (DST) against the four main first-line anti-tuberculosis drugs was performed. RESULTS: A total of 1629 smear-positive tuberculosis (TB) patients were eligible for culture. Of these, DST results were available for 1312 patients, including 1105 new TB cases, 195 previously treated TB cases and 12 cases with an unknown treatment history. The proportion of cases with resistance to any drug was 32.7% (95%CI 29.1-36.5) among new cases and 54.2% (95%CI 44.3-63.7) among previously treated cases. The proportion of multidrug-resistant TB (MDR-TB) cases was 4.0% (95%CI 2.5-5.4) in new cases and 23.3 (95%CI 16.7-29.9) in previously treated cases. CONCLUSIONS: The fourth drug resistance survey in Viet Nam found that the proportion of MDR-TB among new and previously treated cases was not significantly different from that in the 2005 survey. The National TB Programme should prioritise the detection and treatment of MDR-TB to reduce transmission of MDR-TB in the community.

First national tuberculin survey in Viet Nam: characteristics and association with tuberculosis prevalence.

OBJECTIVES: To estimate the prevalence of infection with Mycobacterium tuberculosis and the annual risk of tuberculous infection (ARTI) and to compare this with the prevalence of tuberculosis (TB) over study clusters and households. METHODS: A nationwide, stratified cluster sample survey was carried out in 2006-2007 in Viet Nam to assess the prevalence of infection with M. tuberculosis. A representative sample of children aged 6-14 years underwent a tuberculin skin test (TST) using the Mantoux method. RESULTS: Of 23,160 children registered, 21,487 (92.8%) were tested and read and available for analysis. Using a cut-off point of 10 mm, the estimated prevalence of TST positivity was 16.7%, and the ARTI was 1.7% (95%CI 1.5-1.8). Higher infection rates were found in urban than in rural and remote areas, and infection rates increased with age. There was significant association between the prevalence of TB disease and infection at the cluster level (regression coefficient 0.54, 95%CI 0.06-1.01, P = 0.027, correlation coefficient R(2) 0.120). Children with a (recent) case of TB in the household were 1.6 times more likely to be TST-positive than children in households with no recent cases (P < 0.05). CONCLUSION: The estimated nationwide ARTI was 1.7%. TST positivity was associated with the presence of a TB case in the household.

Yield of interview screening and chest X-ray abnormalities in a tuberculosis prevalence survey.

BACKGROUND: Tuberculosis (TB) prevalence surveys generally rely on a combination of screening methods to identify suspects eligible for sputum culture. OBJECTIVE: To assess the yield of screening methods applied in a recent prevalence survey in Viet Nam and estimate the proportion of TB cases missed due to incomplete participation. METHODS: TB suspects were identified based on self-reported TB history or productive cough by interview and chest X-ray (CXR). We calculated the case yield of these two screening methods by dividing the number of cases detected per method by the total number of cases detected. As not all participants underwent the full screening procedure, we recalculated the maximum yield of the screening methods using multiple imputation methods. RESULTS: The yield from screening by interview and CXR were respectively 38% and 91%. Adjusting for missing data by multiple imputation, we estimated that we missed 9.9% (95%CI 6.8-14.2) of expected TB cases. CONCLUSION: In prevalence surveys, screening by pre-structured interview is insufficient, and should be supplemented with CXR to achieve sufficient identification of TB cases. The effect of incomplete participation in the full screening procedure may be substantial and should be adjusted for in the analysis.

Prevalence and risk factors for tuberculosis infection among personnel in two hospitals in Viet Nam.

SETTING: Two general hospitals in Viet Nam. OBJECTIVE: To assess the risk of tuberculosis (TB) infection associated with hospital employment. DESIGN: During October-December 2009, we performed a cross-sectional study of hospital personnel and, for community comparison groups, staff from nearby schools. We tested for TB infection using the tuberculin skin test; an induration ≥ 10 mm indicated TB infection. RESULTS: Of 956 hospital personnel, 380 (40%) had TB infection compared to 40 (26%) of 155 school personnel. Hospital personnel had twice the odds of TB infection compared with school personnel (OR 2.0, 95%CI 1.3-3.0) after adjustment for age and sex. Compared to hospital administrative staff, the odds of TB infection were similar among clinical staff (OR 1.0, 95%CI 0.6- 1.3), clinical support staff (OR 0.9, 95%CI 0.5-1.6) and auxiliary staff (OR 1.1, 95%CI 0.6-2.0) at the hospitals. No additional infection risk was detected in high-risk departments (OR 1.1, 95%CI 0.6-2.0). CONCLUSIONS: Hospital personnel are at increased risk of TB infection. Among hospital personnel, risk was independent of job or department, suggesting that personnel are commonly at risk and that improvements in infection control are needed throughout hospitals.

Health-seeking behaviour among adults with prolonged cough in Vietnam.

OBJECTIVE: To assess health-seeking behaviour among adults with prolonged cough in a population-based, nationally representative sample in Vietnam. METHODS: Cross-sectional survey conducted from September 2006 to July 2007. All inhabitants aged ≥15 years were invited for screening for cough, history of tuberculosis (TB) treatment and chest X-ray (CXR) examination. TB suspects, defined as any survey participant with CXR abnormalities consistent with TB, or productive cough for more than 2 weeks or TB treatment either currently or in the preceding 2 years submitted sputum specimens for smear examination and culture and provided information on health-seeking behaviour in an in-depth interview. RESULTS: Of 94 179 persons participating in the survey, 4.6% had prolonged productive cough. Forty-four percentage of those had sought health care and reported pharmacies (35%), commune health posts (29%), public hospitals (24%) and private physicians (10%) as first point of contact. Only 7% had undergone sputum smear examination. Of TB suspects with prolonged productive cough, 2.9% were diagnosed with TB; 10.2% of these reported smear and 21.9% reported X-ray examination when visiting a health care facility. The average patient delay was 4.1 weeks (95% CI: 3.9-4.4) among cough suspects and 4.0 weeks (95% CI: 3.1-4.9) among TB cases. CONCLUSIONS: In this Vietnamese survey, nearly half of persons with cough for more than 2 weeks had visited a health care provider. The commonest first health facility contacted was the pharmacy. Sputum smears were rarely examined, except in the provincial TB hospital. Our findings highlight the need to improve diagnostic practices by retraining health staff on the performance of sputum examination for TB suspects.

Household expenditure and tuberculosis prevalence in VietNam: prediction by a set of household indicators.

OBJECTIVE: To study the association between TB and household expenditure in a nationwide TB prevalence survey in Viet Nam using nine household characteristics. METHOD: To assess the prevalence of TB in Viet Nam, a nationwide stratified cluster sample survey was conducted from 2006 to 2007. Nine household characteristics used in the second Viet Nam Living Standards Survey (VLSS) were scored per household. In the VLSS dataset, we regressed these nine characteristics against household expenditure per capita, and used the coefficients to predict household expenditure level (in quintiles) in our survey and assess its relation with TB prevalence. RESULTS: The prevalence of bacteriologically confirmed TB was 307 per 100,000 population in persons aged ≥ 15 years (95%CI 249-366). After adjustment for confounders, prevalence was found to be associated with household expenditure level: the rate was 2.5 times higher for those in the lowest household expenditure quintile (95%CI 1.6-3.9) than those in the highest quintile. CONCLUSION: With a set of nine household characteristics, we were able to predict household expenditure level fairly accurately. There was a significant association between TB prevalence rates and estimated household expenditure level, showing that TB is related to poverty in Viet Nam.

Measurement of exhaled nitric oxide as a potential screening tool for pulmonary tuberculosis.

BACKGROUND: There is a need for low-technology, inexpensive screening tools for active tuberculosis (TB) case finding. OBJECTIVE: to assess the potential usefulness of measuring exhaled nitric oxide (eNO). DESIGN: Cross-sectional comparison in Hanoi, Viet Nam, comparing 90 consecutive smear-positive, culture-confirmed TB patients presenting at a referral hospital with office workers (no X-ray confirming TB) at this hospital (n = 52) and at a construction firm (n = 84). eNO levels were analysed using a validated handheld analyser. RESULTS: eNO levels among TB patients (median 15 parts per billion [ppb], interquartile range [IQR] 10-20) were equal to those among construction firm workers (15 ppb, IQR 12-19, P = 0.517) but higher than those among hospital workers (8.5 ppb, IQR 5-12.5, P < 0.001). Taking the hospital workers as the comparison group, best performance as a diagnostic tool was at a cut-off of 10 ppb, with sensitivity 78% (95%CI 68-86) and specificity 62% (95%CI 47-75). Test characteristics could be optimised to 84% vs. 67% by excluding individuals who had recently smoked or consumed alcohol. CONCLUSION: While eNO measurement has limited value in the direct diagnosis of pulmonary TB, it may be worth developing and evaluating as a cost-effective replacement of chest X-ray in screening algorithms of pulmonary TB where X-ray is not available.

HIV infection among tuberculosis patients in Vietnam: prevalence and impact on tuberculosis notification rates.

BACKGROUND: Vietnam has an emerging human immunodeficiency virus (HIV) epidemic (estimated population prevalence 0.5%), but valid data on HIV prevalence among tuberculosis (TB) patients are limited. Recent increases in TB notification rates among young adults may be related to HIV. OBJECTIVES: To assess the prevalence of HIV infection among smear-positive TB patients in six provinces with relatively high HIV population prevalence in Vietnam. METHODS: All patients who registered for treatment of smear-positive TB during the fourth quarter of 2005 were offered HIV testing. RESULTS: Of the 1217 TB patients included in the study, 100 (8.2%) tested HIV-positive. HIV prevalence varied between 2% and 17% in the provinces, and was strongly associated with age < 35 years, injecting drug use, commercial sex work and a history of sexually transmitted disease. Among men aged 15-34 years, the rate of notification of new smear-positive TB that was attributable to HIV infection varied from 3-4 per 100,000 population in mainly rural provinces to 20-42/100,000 in provinces with rapid industrial and commercial development. CONCLUSION: Among TB patients in Vietnam, HIV infection is concentrated in drug users, as well as in specific geographic areas where it has considerable impact on TB notification rates among men aged 15-34 years.

Decrease in risk of tuberculosis infection despite increase in tuberculosis among young adults in urban Vietnam.

OBJECTIVE: To assess whether the increase in tuberculosis (TB) notification rates among young adults in Vietnam reflects increased transmission in the population at large. METHOD: Trends of case notification rates of new smear-positive TB were calculated from routinely reported data of district TB units over the period 1996-2005. Results from repeated tuberculin surveys among children aged 6-9 years were obtained to calculate the trend in annual risk of TB infection (ARTI). FINDINGS: From 1996 to 2006, notification rates in the age group 15-24 years increased by 4.3% per year, and more so in highly urbanised (6.7%) than in rural districts (1.7%). The ARTI in urban districts declined from 2.4% in 1992 to 1.2% in 1998 and 0.9% in 2005. In rural districts, the ARTI increased from 0.7% in 1991 to 1.2% in 1997, and then declined to 0.9% in 2006. CONCLUSION: The increase in TB notification rates among young adults in Ho Chi Minh Province is accompanied by a decrease in ARTI in children. This suggests that the trend in TB notification among young adults reflects increased rates of progression from infection to disease and/or increased transmission within this age group, rather than increased transmission in the population at large.

High tuberculosis prevalence in a psychiatric hospital in Vietnam.

Little is known about tuberculosis (TB) prevalence in psychiatric hospitals in Vietnam, but prevalence may be higher than in the general population. We assessed the TB prevalence among in-patients of a psychiatric hospital in 2005 in Danang City, Vietnam. Of 300 in-patients, 70 had an abnormal X-ray or prolonged cough, and underwent sputum smear examinations. The prevalence of smear-positive TB was 0.33% (1/300, 95%CI 0.008-1.9). Twenty-three (7.7%) patients had X-ray lesions suggesting active TB and 22 (7.3%) had a history of TB treatment. TB prevalence was high in this psychiatric hospital, and TB infection control needs strengthening.

Population-based chest X-ray screening for pulmonary tuberculosis in people living with HIV/AIDS, An Giang, Vietnam.

SETTING: Human immunodeficiency virus/acquired immune-deficiency syndrome (HIV/AIDS) program, An Giang Province, Vietnam. OBJECTIVE: To evaluate the coverage and yield of a chest radiography (CXR) screening program for tuberculosis (TB) among people living with HIV/AIDS (PLHA), risk factors for a TB CXR, inter-rater reliability of CXR readings and direct costs. DESIGN: Retrospective review of routine public health program records and CXRs. RESULTS: An increasing proportion of PLHAs received a screening CXR each year of the program (range 21% in 2001 to 61% in 2004, P<0.001). Of 876 screening CXRs performed, 191 (22%) were classified as suspicious for active TB ('TB CXR'). Compared to PLHAs with a CXR not suspicious for active TB, PLHAs with a TB CXR were more likely to be aged between 24 and 64 years, male and previously treated for TB (P<0.01 for each comparison). Agreement between the expert and local program CXR readings was 81% (kappa 0.50). Direct costs were approximately US$40 per TB suspect identified. Among TB suspects, <10% were followed up with sputum smear examination and enrolled for treatment. CONCLUSION: In An Giang Province, a large proportion of PLHAs are screened for TB annually, and one in five persons screened is classified as a TB suspect based on CXR. Annual CXRs may be a high-yield, inexpensive method for TB screening in PLHAs, but the follow-up of TB suspects to confirm diagnosis and initiate treatment is crucial.

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.

Capacity building for international tuberculosis control through operations research training.

SETTING: In resource-poor countries, few tuberculosis (TB) program staff at the national, provincial, and even district levels have the basic analytical and epidemiological skills necessary for collecting and analyzing quality data pertaining to national TB control program (NTP) improvements. This includes setting program priorities, operations planning, and implementing and evaluating program activities. OBJECTIVES: To present a model course for building capacity in basic epidemiology and operations research (OR). DESIGN: A combination of didactic lectures and applied field exercises were used to achieve the main objectives of the 6-day OR course. These were to increase the understanding of quantitative and qualitative research concepts, study design, and analytic methods, and to increase awareness of how these methods apply to the epidemiology and control of TB; and to demonstrate the potential uses of OR in answering practical questions on NTP effectiveness. As a final outcome, course participants develop OR proposals that are funded and later implemented. RESULTS: Since 1997, this OR course has been conducted nine times in five countries; 149 key NTP and laboratory staff have been trained in OR methods, and 44 OR protocols have been completed or are underway. CONCLUSION: This low-cost model course can be adapted to a wide range of public health issues.