BMJ Open. Secondary Subject Heading: Health policy, HIV/AIDS, Public health, Health services research

Transcription

1 Impact of methadone maintenance treatment programs on drug users ability to join the workforce in a mountainous area of Northern Vietnam Journal: BMJ Open Manuscript ID bmjopen-0-0 Article Type: Research Date Submitted by the Author: -Jan-0 Complete List of Authors: Nguyen, Lan Huong; Duy Tan University, Institute for Global Health Innovations Nong, Vuong; Institute for Global Health Innovations, Duy Tan University Boggiano, Victoria; University of California Berkeley School of Public Health, Nguyen, Long; School of Medicine and Pharmacy, Vietnam National University Nguyen, Cuong; Institute for Global Health Innovations, Duy Tan University Xuan Bach, Tran; Institute for Preventive Medicine and Public Health, Hanoi Medical University, Health Economics Nguyen, Hung; Authority of HIV/AIDS Control, Ministry of Health Hoang, Canh; Authority of HIV/AIDS Control, Ministry of Health Latkin, Carl; Johns Hopkins School of Public Health, Health, Behavior, and Society Vu, Minh Thuc; Department of Immunology and Allergy, National Otolaryngology Hospital <b>primary Subject Heading</b>: Public health Secondary Subject Heading: Health policy, HIV/AIDS, Public health, Health services research Keywords: drug use, methadone, ability, workforce, mountainous, Vietnam BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

2 Page of BMJ Open Impact of methadone maintenance treatment programs on drug users ability to join the workforce in a mountainous area of Northern Vietnam Huong Lan Thi Nguyen *, Vuong Minh Nong *, Victoria L. Boggiano *, Cuong Tat Nguyen, Long Nguyen Hoang, Bach Xuan Tran,, Hung Van Nguyen, Canh Dinh Hoang, Carl A. Latkin, Vu Thi Minh Thuc Institute for Global Health Innovations, Duy Tan University, Da Nang, Vietnam University of California, Berkeley School of Public Health, Berkeley, California School of Medicine and Pharmacy, Vietnam National University, Hanoi, Vietnam Institute for Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America Authority of HIV/AIDS Control, Ministry of Health, Hanoi, Vietnam Department of Immunology and Allergy, National Otolaryngology Hospital, Hanoi, Vietnam * Equally contributed. Corresponding author: Huong Lan Thi Nguyen, Msc. Institute for Global Health Innovations, Duy Tan University, Da Nang, Vietnam, nguyentlanhuong@duytan.edu.vn Word count: Keywords: drug use, methadone, ability, workforce, mountainous, Vietnam BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

3 Page of ABSTRACT Objectives: A major measure of treatment success for drug users undergoing rehabilitation is the ability to enter the workforce and generate an income. This study examines the impact of methadone maintenance treatment (MMT) programs on productivity and workability among injection drug users (IDUs) in Northern Vietnam. Setting: A cross-sectional study was conducted in two clinics in Tuyen Quang province. Participants: A total of patients enrolled in MMT Primary and secondary outcome measures: Patients work productivity was measured using the WPAI-GH instrument (Work Productivity and Activity Impairment Questionnaire: General Health V.0). We also collected additional characteristics about participants employment history, such as proficient jobs, whether they actively found a new job and be accepted by employers. Results: Most of participants (more than 0%) were employed at the time of the study. Rates of absenteeism (missed work), presenteeism (impairment while working), and overall loss of productivity were.%,.%, and.%, respectively, as measured by the WPAI-GH questionnaire. The most proficient job was freelancer, followed by bluecollar worker and farmer. Only.% of patients reported actively looking for a job, half of whom had been denied work because of their drug use history and/or HIV status. We found no statistically significant difference between patients enrolled in MMT for less than one year and those who had been enrolled more than one year. Factors associated with higher work productivity included higher income; not endorsing problems in mobility, self-care, or pain; being HIV-negative; and having higher treatment adherence. Conclusion: Our study highlights the great impact that MMT programs can have on employment status and work productivity among IDUs in remote areas of Northern Vietnam. The results can help to improve the quality and structure of MMT programs across Vietnam and in other countries. Strengths and limitations of this study A cross-sectional study design was used without a comparison group. A small sample size may negatively impact the statistical power of this study. Data is based on patients self-reports, which may lead to recall bias. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

4 Page of BMJ Open INTRODUCTION Injection drug users (IDUs) represent a major public health burden. Globally, there are more than million IDUs []. It is widely accepted that injecting drugs is associated with a high risk of acquiring HIV and hepatitis, as well as the risk of falling victim to drug overdose or mental health problems [ ]. These risk factors contribute to the higher mortality rate and lower quality of life among IDUs compared with the general population [ ]. Yet the consequences of illicit drug use are not only in regards to health aspect. In both developed and developing countries, using drugs has significant social and economic effects. The economic cost of drug abuse in the United States is estimated to be $, per year, with the major driver of this cost was productivity losses []. Similar results have also been found among Taiwanese IDUs []. The loss of work productivity among opioid-dependent drug users is an inevitable outcome of their reduction in health status, early mortality, and difficulty finding legal means of employment [ ]. Methadone maintenance treatment (MMT) is known to be one of the most efficacious therapies for opiate addiction [ 0]. IDUs enrolled in MMT programs can significantly reduce heroin and other opioid use []. In addition, IDUs enrolled in MMT are less likely to engage in criminal activities or be at risk of HIV acquisition; their health-related quality of life also tends to get better when they are on the program [ -]. IDUs' socioeconomic status also show to be improved. Corsi el al. found an increase in employment and self-derived income between baseline and six months after enrollment in an MMT clinic among 0 IDUs in the United States []. In Taiwan, Hsiao et. al. found that the mean length of unemployment was cut in half among patients enrolled in MMT, in conjunction with an increase in patients monthly income []. In Vietnam, the HIV epidemic is driven primarily by injection drug use. Approximately 0.% to.% of the IDUs in Vietnam are HIV-positive []. Over the past five years, the HIV epidemic in Vietnam has seen remarkable growth in mountainous and remote areas of the country. For example, in Dien Bien and Son La, two provinces in the northwestern part of Vietnam, the HIV rate among IDUs is estimated to be 0.% and.%, respectively []. To address this rise in HIV among IDUs, there has been a rapid expansion of MMT in many provinces. In the year 0, there were more than 00 MMT clinics present in provinces and cities across Vietnam, providing treatment to about,000 patients, according to the Vietnam National HIV/AIDS Report [0]. Recent studies in Vietnam have highlighted the effectiveness of MMT in reducing HIV-related risk behaviors and health expenditure among IDUs, as well as increasing their health status and quality of life [-]. However, limited data exists about the socioeconomic impact of MMT. A study by Hoang et al. indicated that MMT patients in an urban city in Vietnam saw improved employment rates and increased income, but the their results BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

5 Page of did not measure actual productivity gained or lost by being enrolled in MMT []. HIV prevention and treatment programs in Vietnam are at risk of rapidly losing funding from international donors, and co-payment services might be a potential way to cope with this problem []. Yet in order to expand the programs, their ability to join the workforce must be better understood. In this study, we assessed productivity and preferences about employment among IDUs enrolled in two MMT programs in a mountainous part of Northern Vietnam. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

6 Page of BMJ Open METHODS Study design and setting A clinic-based cross sectional study was carried out in Tuyen Quang, a mountainous province in Northeastern Vietnam from May to August 0. We involved two MMT clinics namely Tuyen Quang City and Son Duong clinics. The former is placed in an urban area while the latter located in a remote area of the province. A convenient sampling technique was used to recruit the patients. Patients were invited if they were years old or above, available during study period, able to answer a questionnaire in 0- minutes and accepted to involve in the study. After introducing to the study, the patients were asked to give their written informed consent if they agreed to be study subjects. Totally, patients participated in the study. Measurements and instruments We conducted face-to-face interviews with the patients by using a structured questionnaire. The data collection team included master students in Public Health from Hanoi Medical Unniversity. The variables of interest are described below: Socioeconomic characteristics Participants socioeconomic characteristics were recorded, including age, gender, education level, marital status, employment status, ethnicity, religion, and household monthly income. Work productivity Participants overall productivity and loss of productivity due to their drug addiction was measured using the Work Productivity and Activity Impairment Questionnaire: General Health V.0 (WPAI-GH) []. The instrument contains six questions that measures work lost due to an impairment: Q. Current employment; ; ;Q. Hours missed due to a specified problem; Q. Hours missed for other reasons; Q. Total hours worked; Q. Degree that problem affects productivity while working; Q. Degree that problem impacts regular activities. We calculated four primary outcomes based on these questions [ ], including:. Percent of work time missed due to health condition (absenteeism). Percent impairment while working due to health condition (presenteeism).. Percent overall work impairment due to health. Percent impairment in activities due to health. Moreover, we also collected additional characteristics about participants employment history, such as the types of jobs they were proficient at, whether they had recently BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

7 Page of found a new job, and whether employers had offered them jobs or not (including reasons for being turned away if applicable). Health status EuroQol - five dimensions - five levels (EQ-D-L) instrument was used to measure HRQOL in five domains: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. There are five levels of response for each domain: no problems, slight problems, moderate problems, severe problems, and extreme problems [ ]. We also employed a visual analogue scale (VAS) to measure self-evaluated HRQOL. This scale had the score ranging from 0 ( The worst heatlh state that you can imagine ) to 00 ( The best health state that you can imagine). We also asked patients to report their HIV status, history of suffering acute diseases in the last four weeks and experiencing chronic diseases in the last three months. Additionally, self-reported weight and height were collected to compute the body mass index, which can classify the patients into three groups Underweight, Normal and Overweight/Obesity. Data about whether the patients received ART was collected. Substances abuse characteristics Patients with alcohol abuse were screened by using the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C), an instrument having three items with the total score from 0 to []. The higher score means the higher risk of alcohol abuse. If male respondents have a score, and if female respondents have a score, they are categorized as hazardous drinkers []. In terms of cigarette smoking, respondents were categorized as current smokers if they have ever smoked at least 00 cigarettes in their entire life and had smoked in the last 0 days. We also collected information about participants concurrent drug use and the number of times they underwent drug rehabilitation and duration of methadone treatment. MMT adherence Patients reported their adherence to MMT over the past 0 days on a 00-point visual analog scale (VAS), where 0 indicated complete non-adherence and 00 indicated perfect adherence. The optimal threshold to identify Adherence was point or above [0]. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

8 Page of BMJ Open Statistical analysis Data was analyzed using STATA software version.0 (Stata Corp. LP, College Station, United States of America). T-tests and Chi-square tests were used to detect differences among charateristics. A p-value <0.0 was considered statistically significant. In this study, a stepwise backward selection strategy was applied, along with multivariate logistic and tobit regressions, to create reduced models. This strategy used a log-likelihood ratio test threshold that enabled predictors with p-values of < 0. to be included. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

9 Page of RESULTS Table highlights the demographic characteristics of study respondents. Most of participants were young adults or middle-age, with about % of participants from 0-0 years old and % of participants from 0-0 years old. About half of participants (%) did not finish high school, and over 0% were current living with a spouse/ partner. The majority of respondents were currently employed (.%), but most of them were selfemployed (.%). Table. Demographic characteristics of respondents Characteristic Age group MMT duration <= months MMT duration > months N % N % N % Total p- value < 0 years old years old years old >=0 years old... Gender Male Educational Attainment Less than high school High school.. 0. More than high school... Marital status Single Live with spouse/partner... Widow/Separate/Divorced... Job Unemployed Farmer/Worker... Self-employed Other.. 0. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

10 Page of BMJ Open Ethnicity Characteristic MMT duration <= months MMT duration > months N % N % N % Total p- value Kinh Location Son Duong Tuyen Quang. 0.. Health-related characteristics and substance use behaviors among respondents are described in Table. We found that.% of respondents were HIV-positive, and about % were currently on ARV treatment. About % of patients reported mobility problems, and over.% endorsed experiencing pain or discomfort. Thirty-one patients stated they were engaging in concurrent drug use during treatment with methadone (.%). Approximately % of patients were current smokers, and.% were hazardous drinkers. The proportion of patients have optimal adherence to MMT was.%. Table. Health status and substance use behaviors among respondents Characteristics MMT duration <= months MMT duration > months Total N % N % N % p-value Having acute diseases Having chronic diseases BMI categories Underweight Normal... Overweight/Obesity... HRQOL Having problems in mobility Having problems in self-care BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

11 Page 0 of Characteristics MMT duration <= months 0 MMT duration > months Total N % N % N % p-value Having problems in usual activities Pain/Discomfort Anxiety/Depression HIV positive ART treatment Current smoker Current hazardous drinker Current drug use Number of drug rehabilitation 0 times times. 0.. times..0. > times... Adhered to MMT Mean SD Mean SD Mean SD p-value EQD index score VAS score Work productivity among respondents, as measured by the WPAI-GH, is presented in Table. The rate of absenteeism (percentage of work time missed due to poor health) was.% (SD=.). The rate of presenteeism (percentage of reduction in work performance because of poor health) was lower than the rate of absenteeism, at.% (SD=.0). The overall loss of productivity because of poor health among the entire sample was.%. We did not find a statistically significant difference in productivity lost between patients who had been enrolled in MMT for one year or less and those who had been enrolled in MMT for more than one year. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

12 Page of BMJ Open Table. Work productivity among respondents Characteristics Percent work time missed because of poor health MMT duration <= months Percent impairment while working because of poor health Percent overall work impairment because of poor health Percent activity impairment because of poor health MMT duration > months Total Mean SD Mean SD Mean SD p- value Table describes characteristics related to work capability among the participants in our study. The most popular job endorsed by respondents was as a free-lancer (.%), followed by being a blue-collar worker (0.%), a farmer (0.%), and a small business owner (.%). The proportion of respondents who could actively seeking jobs was low (.%). Among the patients currently employment, there were.% who reported not being accepted by an employer. Among the patients who were refused jobs, the main reason for refusal was that they were drug users, endorsed by respondents (.%). The preferred minimum wage at which to accept a job was. million VND. Table. Work capability among respondents Characteristics Currently working at a sustainable job MMT duration <= months MMT duration > months N % N % N % Total p- value Blue-collar Farmer Small business at home 0... BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

13 Page of Freelancer... Others. 0.. Actively finding a job No Yes... Being accepted by an employer Yes No.0.. Minimum salary to accept job (Mil VND) Reason for not being accepted by employer (if applicable) Mean SD Mean SD Mean SD p- value n % Drug user. HIV Patients. Insufficient capacity. Unknown 0. Table shows the factors associated with working time missed due to health, overall work impairment due to health, and ability to actively find jobs among respondents. Patients with higher incomes were significantly more likely to have better work productivity (p<0.0). Those who were HIV-positive and/or had other chronic diseases were found to be less actively searching for jobs than other participants (OR=0., p<0.0). Various health-related characteristic were found to be related to decreased work productivity, including experiencing problems with self-care, experiencing problems with mobility, and having pain/discomfort. Higher MMT adherence was associated with higher ability to work; however, a weak association was found between duration of treatment and a participant s workability. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

14 Page of BMJ Open Table. Factors associated with work capability among respondents Characteristics Percent work time missed due to health Age 0.* -0.. Marital status (vs Single) Percent overall work impairment due to health Actively finding jobs Coef % CI Coef % CI OR % CI Live with spouse/partner 0.*** Income quintile (vs poorest) Poor -.*** *** Middle -.*** *** * 0.. Rich -.*** *** Richest -.** *** * 0.. Experiencing problems in mobility (Yes vs No).* -.0. Experiencing problems in self-care (Yes vs No).0***...0**.. Experiencing problems in usual activities (Yes vs No) -.** ** Pain/Discomfort (Yes vs No).**.. Anxiety/Depression (Yes vs No) -.*** ***.. EQ-VAS -0.*** ** Having acute diseases (Yes vs No) Having chronic diseases (Yes vs No) -0.* ** on 0 December 0 by guest. Protected by copyright. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from

15 Page of BMI (vs Underweight) Characteristics Percent work time missed due to health Percent overall work impairment due to health Actively finding jobs Coef % CI Coef % CI OR % CI Normal.**.0.0 Overweight and Obesity 0.0**. 0. HIV status (vs Negative) Positive.** * 0.. Current smoker (Yes vs No) **.. Adherent to MMT (Yes vs No) -.*** *** Taking ARV treatment (Yes vs No).**...***.. Duration of MMT 0.* Number of drug rehabilitation (vs None) time times > times -0.0** Location (Son Duong vs Tuyen Quang).**. 0..0* 0.. *** p<0.0, ** p<0.0, * p<0. on 0 December 0 by guest. Protected by copyright. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from

16 Page of BMJ Open DISCUSSION While previous studies have documented MMT outcomes among drug users in Vietnam in term of behavior and health-related quality of life [-], our study is the first to measure how MMT relates to patients work capability and overall level of productivity. Our findings may provide evidence regarding the benefits of MMT, as well as shed light on future directions to expand and improve the efficacy of MMT programs in Vietnam. We found a high rate of employment among MMT patients in Tuyen Quang Province. Over 0% of participants in our sample reported currently holding a regular job. According to the 0 Vietnamese National Report on Labor Survey, the employment-to population ratio in the Northern Midlands and other northern mountainous areas of the country ranged from. to %, and ratio nationwide was about.% to.% []. The employment rate among non-mmt IDUs was reported to be between.% and.%, according to various studies [-]. Compared to these numbers, the employment-to-population ratio among the IDUs in our study was slightly higher. One possible explanation for this higher ratio might be that most of participants in our study were young adults or middle aged, which represent the two primary age ranges of the Vietnamese workforce. In addition, the Vietnamese Ministry of Health and international partners have gone to great lengths to expand substitution therapy for IDUs (included MMT) and other social support interventions, which likely helped increase the employment rate in this population [-]. Nonetheless, most of participants jobs were unstable (and nearly half of participants were self-employed). Other studies in Vietnam found similar results; indeed, on average, over 0% of methadone patients in Vietnam do not able to participate in stable and long-time employment [ ]. This may due to the low level of educational attainment and lack of vocational skills among IDUs in Vietnam, particularly in a remote area like Tuyen Quang. Our results showed that a very low proportion of participants had a higher degree, and about half of them did not finish high school. They were mainly proficient at low-skill jobs such as being a free-lancer or working as a blue-collar worker. The Government of Vietnam, collaborated with international groups, has established several policies and interventions to support the creation of employment opportunities for IDUs after treatment, including vocational training, financial assistance, and peer support groups [-]. However, these endeavors have some notable limitations. First, there is a lack of diversity within the workforce in Vietnam. Many patients may not be able to apply what they have learned after returning to the community because of the reality of the demands of the country s labor market. In addition, despite being successful in treatment, IDUs may still suffer from many health problems including HIV and psychological ailments. In our study, the HIV-positive rate BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

17 Page of was.% among participants, and those who had HIV and other chronic diseases were less likely to actively finding jobs. In addition, for a long time, people who inject drugs in Vietnam have been judged as engaging in social evils and faced a variety of barriers due to stigma and discrimination. Such barriers may pose the biggest threat to their ability to find stable employment. A study by Tran BX, et. al., found that enrollment in MMT may reduce internalized stigma and discrimination among IDUs [0]. However, in our sample, the rate of experiencing blame, shame, and isolation from the community and the workplace were relative high []. Moreover, more than half of the individuals who participated in our study (particularly those who were HIV-positive) had been turned away by employers in the past. Using the WPAI-GH instrument, we found a very low level of impairment in work productivity and daily activities among respondents. These results highlight the positive impact of MMT on work productivity outcomes among IDUs. Similar results have been noted in other countries. A one-year study conducted among IDUs enrolled in MMT in Taiwan found that individuals enrolled in MMT saw decreased expenditures for illegal drugs and health services, in conjunction with a rise in employment []. Employment and income rates increased by half among patients in the United States after months of being on MMT in a study conducted by Corsi, et al. []. In our study, we identified various factors that were associated with lost productivity among respondents. First, in terms of socioeconomic characteristics, we found that patients with higher incomes missed less work time and had overall reduced work impairment. This result suggests that Vietnam may want to invest in more vocational training opportunities for MMT patients. Conversely, respondents who endorsed problems in mobility, self-care and pain were more likely to report a higher loss of productivity. Additionally, patients who were HIV-positive and currently taking ARV had higher rates of absenteeism than other participants. Many studies have demonstrated the drug interactions between ARV and methadone, which require patients to take higher doses of methadone in order to see an effect [ ]. After taking such a high dose, patients will suffer from a range of side effects, including sleep problems, nausea, and vomiting [], which may reduce their performance and ability to work. Thus, for HIV-positive IDUs, collaboration between health workers at MMT and ARV clinics is necessary. Other health conditions including health nutrition status and the co-existence of other chronic diseases were also shown to be associated with patients' ability to join the work force. Overall, our findings confirmed the results of other studies recommending that HIV prevention and treatment services, as well as general health care services, should be integrated to maximize the effectiveness of each of the programs [ ]. The influence of MMT-related characteristics on work productivity was also presented in this study. Our model showed that patients who had optimal adherence were more likely BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

18 Page of BMJ Open to have higher work performance than non-adherent ones. This can be explained by the fact that good compliance with the treatment course was associated with reduced mortality and better health-related quality of life outcomes among IDUs [ ], as well as decreased loss in productivity. Other factors such as the duration of MMT, depression, and concurrent substance abuse were found to have no or weak correlation with rates of absenteeism and overall work impairment. Our study points to several ways to improve the efficiency of MMT and HIV/AIDS services in Vietnam. First, a high proportion of the participants in our study were employed; however, the high proportion of participants held unstable occupations and did not require many skills. This suggests that current vocational training and career support may not be sufficient to meet the career demands of this population. Future jobrelated policy for MMT patients should be based on the preferences and the demands of the patients and the labor market. In addition, a numbers of patients reported that they were not accepted by an employer because of their drug use history and HIV status. This finding reflects the considerable stigma and discrimination toward IDUs and people living with HIV/ADS in Vietnam that still exists. Follow-up interventions should be conducted in a synchronous manner to more efficiently to remove the barrier of stigma and discrimination. We also found several health-related characteristics, including being HIV-positive, co-treatment with MMT and ARV, and endorsing significant pain, were associated with lower work productivity among participants. Therefore, integrating MMT with other healthcare services is necessary in order to see improved work productivity outcomes. Counseling during treatment to improve and maintain patients adherence to treatment is also important. This study has several limitations. First, we employed a cross-sectional study design without a control group. Thus, we cannot compare changes in outcomes for the people in our study as compared to others without similar exposure. To best account for this limitation, we divided our sample into two groups: one that included individuals who had been in MMT for one year or less, and another group that had been in MMT for more than one year. Yet our small sample size may negatively impact the statistical power of our study. Another limitation is that our data is based on patients self-reports, which may lead to recall bias. CONCLUSION In conclusion, our study highlights the great impact that MMT programs can have on employment status and productivity among IDUs in a remote area of Vietnam. Various factors associated with workability have been determined through our work, which could be useful in helping to improve the quality and expansion of MMT programs across the country. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

19 Page of Acknowledgements We would like to thank the patients and their families for for their participation in this study. We would also like to thank The Vietnam Authority of HIV/AIDS Control, The Hanoi School of Public Health, and the Tuyen Quang Provincial Aids Center for their help and support. Ethics approval and consent to participate This study s protocol was approved by the IRB of Vietnam Authority of HIV/AIDS Control. Data collection procedures were also approved by the directors of the MMT clinics. Written informed consent was obtained from all participants. Competing interests The authors declare that they have no competing interests. Funding There was no funding for this analysis Authors contributions HLTN, VNM, VLB, CTN, LHN, BXT, HVN, CHD, CAL, VTMT conceived of the study, and participated in its design and implementation and wrote the manuscript. HLTN, VMN and CTN analyzed the data. All authors read and approved the final manuscript. Availability of data and materials The data that support the findings of this study were made available by the Vietnam Authority of HIV/AIDS Control, but there were a few restrictions on the availability of these data. The data was used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission from the Vietnam Authority of HIV/AIDS Control. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

20 Page of BMJ Open References. Degenhardt L, Whiteford HA, Ferrari AJ, et al. Global burden of disease attributable to illicit drug use and dependence: findings from the Global Burden of Disease Study 00. The Lancet;(0):- doi: 0.0/S00-()0-[published Online First: Epub Date].. Mathers BM, Degenhardt L, Phillips B, et al. Global epidemiology of injecting drug use and HIV among people who inject drugs: a systematic review. Lancet (London, England) 00;():- doi: 0.0/s00-(0)-[published Online First: Epub Date].. Nelson PK, Mathers BM, Cowie B, et al. Global epidemiology of hepatitis B and hepatitis C in people who inject drugs: results of systematic reviews. Lancet (London, England) 0;():- doi: 0.0/s00-()0-0[published Online First: Epub Date].. Mathers BM, Degenhardt L, Bucello C, Lemon J, Wiessing L, Hickman M. Mortality among people who inject drugs: a systematic review and meta-analysis. Bulletin of the World Health Organization 0;():0- doi: 0./blt..0[published Online First: Epub Date].. Cartwright WS. Economic costs of drug abuse: Financial, cost of illness, and services. Journal of Substance Abuse Treatment;():- doi: 0.0/j.jsat [published Online First: Epub Date].. Lin S-H, Chen KC, Lee S-Y, et al. The economic cost of heroin dependency and quality of life among heroin users in Taiwan. Psychiatry Research;0():- doi: 0.0/j.psychres.0.0.0[published Online First: Epub Date].. Richardson L, Wood E, Li K, Kerr T. Factors associated with employment among a cohort of injection drug users. Drug and alcohol review 00;():-00 doi: 0./j x[published Online First: Epub Date].. French MT, Roebuck MC, Alexandre PK, xe, breau. Illicit Drug Use, Employment, and Labor Force Participation. Southern Economic Journal 00;():- doi: 0.0/0[published Online First: Epub Date].. Mattick RP, Breen C, Kimber J, Davoli M. Methadone maintenance therapy versus no opioid replacement therapy for opioid dependence. The Cochrane database of systematic reviews 00():Cd000 doi: 0.00/.CD000.pub[published Online First: Epub Date]. 0. Mattick RP, Breen C, Kimber J, Davoli M. Buprenorphine maintenance versus placebo or methadone maintenance for opioid dependence. The Cochrane database of systematic reviews 0():Cd000 doi: 0.00/.CD000.pub[published Online First: Epub Date].. Sun HM, Li XY, Chow EP, et al. Methadone maintenance treatment programme reduces criminal activity and improves social well-being of drug users in China: a systematic review and metaanalysis. BMJ open 0;():e00 doi: 0./bmjopen-0-00[published Online First: Epub Date].. Gowing L, Farrell M, Bornemann R, Sullivan L, Ali R. Substitution treatment of injecting opioid users for prevention of HIV infection. The Cochrane database of systematic reviews 00():Cd00 doi: 0.00/.CD00.pub[published Online First: Epub Date].. Karki P, Shrestha R, Huedo-Medina TB, Copenhaver M. The Impact of Methadone Maintenance Treatment on HIV Risk Behaviors among High-Risk Injection Drug Users: A Systematic Review. Evidence-based medicine & public health 0;:e. Xiao L, Wu Z, Luo W, Wei X. Quality of life of outpatients in methadone maintenance treatment clinics. Journal of acquired immune deficiency syndromes () 00; Suppl :S-0 doi: 0.0/QAI.0b0ecdfb[published Online First: Epub Date]. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

21 Page 0 of Wang PW, Wu HC, Yen CN, et al. Change in quality of life and its predictors in heroin users receiving methadone maintenance treatment in Taiwan: an -month follow-up study. The American journal of drug and alcohol abuse 0;():- doi: 0.0/000.0.[published Online First: Epub Date].. Baharom N, Hassan MR, Ali N, Shah SA. Improvement of quality of life following months of methadone maintenance therapy in Malaysia. Substance Abuse Treatment, Prevention, and Policy 0;(): doi: 0./-x--[published Online First: Epub Date].. Corsi KF, Lehman WK, Booth RE. The effect of methadone maintenance on positive outcomes for opiate injection drug users. Journal of substance abuse treatment 00;():0- doi: 0.0/j.jsat [published Online First: Epub Date].. Hsiao CY, Chen KC, Lee LT, et al. The reductions in monetary cost and gains in productivity with methadone maintenance treatment: one year follow-up. Psychiatry Res 0;():- doi: 0.0/j.psychres.0..0[published Online First: Epub Date].. MOH. HIV/STI Integrated Biological and Behavioral Surveillance (IBBS) in Vietnam: Round III. Hanoi, MOH. Vietnam National Response to HIV/AIDS Report. Hanoi, 0.. Tran BX, Nguyen LT. Impact of methadone maintenance on health utility, health care utilization and expenditure in drug users with HIV/AIDS. The International journal on drug policy 0;():e0-0 doi: 0.0/j.drugpo [published Online First: Epub Date].. Tran BX, Ohinmaa A, Duong AT, et al. Cost-effectiveness of methadone maintenance treatment for HIV-positive drug users in Vietnam. AIDS care 0;():-0 doi: 0.00/ [published Online First: Epub Date].. Tran BX, Nguyen LH, Nong VM, Nguyen CT, Phan HT, Latkin CA. Behavioral and quality-of-life outcomes in different service models for methadone maintenance treatment in Vietnam. Harm reduction journal 0;: doi: 0./s-0-00-[published Online First: Epub Date].. Hoang TV, Ha TT, Hoang TM, et al. Impact of a methadone maintenance therapy pilot in Vietnam and its role in a scaled-up response. Harm reduction journal 0;: doi: 0./s-0-00-[published Online First: Epub Date].. Tran BX, Phan HT, Nguyen LH, et al. Economic vulnerability of methadone maintenance patients: Implications for policies on co-payment services. The International journal on drug policy 0;:- doi: 0.0/j.drugpo.0.0.0[published Online First: Epub Date].. Reilly MC, Zbrozek AS, Dukes EM. The validity and reproducibility of a work productivity and activity impairment instrument. PharmacoEconomics ;():-. dacosta DiBonaventura M, Gupta S, Cho M, Mrus J. The association of HIV/AIDS treatment side effects with health status, work productivity, and resource use. AIDS care 0;():- doi: 0.00/00.0.0[published Online First: Epub Date].. Group E. EQ-D-L User Guide: Basic information on how to use the EQ-D-L instrument. Secondary EQ-D-L User Guide: Basic information on how to use the EQ-D-L instrument 0. Q-D-L.pdf.. Bradley KA, DeBenedetti AF, Volk RJ, Williams EC, Frank D, Kivlahan DR. AUDIT-C as a brief screen for alcohol misuse in primary care. Alcoholism, clinical and experimental research 00;():0- doi: 0./j x[published Online First: Epub Date]. 0. Giordano TP, Guzman D, Clark R, Charlebois ED, Bangsberg DR. Measuring adherence to antiretroviral therapy in a diverse population using a visual analogue scale. HIV clinical trials 00;():- doi: 0.0/jfxh-gx-eym-dug[published Online First: Epub Date].. Office" VGS. Report on Labor Force Survey 0. Hanoi: Ministry of Investment and Planing, 0. 0 BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

22 Page of BMJ Open Quan VM, Go VF, Van Nam L, et al. Risks for HIV, HBV, and HCV infections among male injection drug users in northern Vietnam: A case-control study. AIDS care 00;():- doi: 0.00/000000[published Online First: Epub Date].. Go VF, Frangakis C, Le Minh N, et al. Effects of an HIV peer prevention intervention on sexual and injecting risk behaviors among injecting drug users and their risk partners in Thai Nguyen, Vietnam: A randomized controlled trial. Social science & medicine () 0;:- doi: 0.0/j.socscimed [published Online First: Epub Date].. Go VF, Le Minh N, Frangakis C, et al. Decreased injecting is associated with increased alcohol consumption among injecting drug users in northern Vietnam. The International journal on drug policy 0;():0- doi: 0.0/j.drugpo.0..00[published Online First: Epub Date].. Nguyen TT, Nguyen LT, Pham MD, Vu HH, Mulvey KP. Methadone maintenance therapy in Vietnam: an overview and scaling-up plan. Advances in preventive medicine 0;0: doi: 0./0/[published Online First: Epub Date].. Le LT, Grau LE, Nguyen HH, Khuat OH, Heimer R. Coalition building by drug user and sex worker community-based organizations in Vietnam can lead to improved interactions with government agencies: a qualitative study. Harm reduction journal 0;: doi: 0./s [published Online First: Epub Date].. Hayes-Larson E, Grau LE, Khoshnood K, Barbour R, Khuat OTH, Heimer R. Drug users in Hanoi, Vietnam: factors associated with membership in community-based drug user groups. Harm reduction journal 0;0:- doi: 0./--0-[published Online First: Epub Date].. Li L, Hien NT, Lin C, et al. An intervention to improve mental health and family well-being of injecting drug users and family members in Vietnam. Psychology of addictive behaviors : journal of the Society of Psychologists in Addictive Behaviors 0;():0- doi: 0.0/a00[published Online First: Epub Date].. Ahmed T, Long NT, Huong PTT, Stewart DE. HIV and Injecting Drug Users in Vietnam: An Overview of Policies and Responses. World Medical & Health Policy 0;():- doi: 0.00/wmh.[published Online First: Epub Date]. 0. Tran BX, Vu PB, Nguyen LH, et al. Drug addiction stigma in relation to methadone maintenance treatment by different service delivery models in Vietnam. BMC Public Health 0;: doi: 0./s-0--0[published Online First: Epub Date].. Van Nguyen H, Nguyen HL, Mai HT, et al. Stigmatization among methadone maintenance treatment patients in mountainous areas in northern Vietnam. Harm reduction journal 0;(): doi: 0./s-0-0-[published Online First: Epub Date].. Hsiao CY, Chen KC, Lee L-T, et al. The reductions in monetary cost and gains in productivity with methadone maintenance treatment: One year follow-up. Psychiatry Research;():- doi: 0.0/j.psychres.0..0[published Online First: Epub Date].. Gourevitch MN, Friedland GH. Interactions between methadone and medications used to treat HIV infection: a review. The Mount Sinai journal of medicine, New York 000;(-):-. Gerber JG, Rosenkranz S, Segal Y, et al. Effect of ritonavir/saquinavir on stereoselective pharmacokinetics of methadone: results of AIDS Clinical Trials Group (ACTG) 0. Journal of acquired immune deficiency syndromes () 00;():-0. Zhao L, Holzemer WL, Johnson M, Tulsky JP, Rose CD. HIV infection as a predictor of methadone maintenance outcomes in Chinese injection drug users. AIDS care 0;():-0 doi: 0.00/00.0.0[published Online First: Epub Date]. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

23 Page of Tran BX, Nguyen LH, Phan HT, Latkin CA. Patient Satisfaction with Methadone Maintenance Treatment in Vietnam: A Comparison of Different Integrative-Service Delivery Models. PloS one 0;0():e0 doi: 0./journal.pone.0[published Online First: Epub Date].. Kato M, Granich R, Bui DD, et al. The Potential Impact of Expanding Antiretroviral Therapy and Combination Prevention in Vietnam: Towards Elimination of HIV Transmission. Journal of acquired immune deficiency syndromes () 0;():e-e doi: 0.0/QAI.0b0ebb[published Online First: Epub Date].. Tran BX, Ohinmaa A, Duong AT, et al. Changes in drug use are associated with health-related quality of life improvements among methadone maintenance patients with HIV/AIDS. Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation 0;():- doi: 0.00/s-0--y[published Online First: Epub Date].. Cao X, Wu Z, Li L, et al. Mortality among Methadone Maintenance Clients in China: A Six-Year Cohort Study. PLOS ONE 0;():e doi: 0./journal.pone.00[published Online First: Epub Date]. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.

24 Page of BMJ Open Section/Topic Item # STROBE 00 (v) Statement Checklist of items that should be included in reports of cross-sectional studies Recommendation Reported on page # Title and abstract (a) Indicate the study s design with a commonly used term in the title or the abstract Introduction (b) Provide in the abstract an informative and balanced summary of what was done and what was found Background/rationale Explain the scientific background and rationale for the investigation being reported Objectives State specific objectives, including any prespecified hypotheses Methods Study design Present key elements of study design early in the paper Setting Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection Participants (a) Give the eligibility criteria, and the sources and methods of selection of participants Variables Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if Data sources/ measurement applicable * For each variable of interest, give sources of data and details of methods of assessment (measurement). Describe comparability of assessment methods if there is more than one group Bias Describe any efforts to address potential sources of bias Study size 0 Explain how the study size was arrived at Quantitative variables Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why Statistical methods (a) Describe all statistical methods, including those used to control for confounding Results (b) Describe any methods used to examine subgroups and interactions (c) Explain how missing data were addressed (d) If applicable, describe analytical methods taking account of sampling strategy (e) Describe any sensitivity analyses on 0 December 0 by guest. Protected by copyright. BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from

25 Page of Participants * (a) Report numbers of individuals at each stage of study eg numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analysed (b) Give reasons for non-participation at each stage Descriptive data (c) Consider use of a flow diagram * (a) Give characteristics of study participants (eg demographic, clinical, social) and information on exposures and potential confounders (b) Indicate number of participants with missing data for each variable of interest Outcome data * Report numbers of outcome events or summary measures, Main results (a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (eg, % confidence interval). Make clear which confounders were adjusted for and why they were included (b) Report category boundaries when continuous variables were categorized (c) If relevant, consider translating estimates of relative risk into absolute risk for a meaningful time period Other analyses Report other analyses done eg analyses of subgroups and interactions, and sensitivity analyses Discussion Key results Summarise key results with reference to study objectives Limitations Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias Interpretation 0 Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from,, similar studies, and other relevant evidence Generalisability Discuss the generalisability (external validity) of the study results Other information Funding Give the source of funding and the role of the funders for the present study and, if applicable, for the original study on which the present article is based *Give information separately for cases and controls in case-control studies and, if applicable, for exposed and unexposed groups in cohort and cross-sectional studies. Note: An Explanation and Elaboration article discusses each checklist item and gives methodological background and published examples of transparent reporting. The STROBE checklist is best used in conjunction with this article (freely available on the Web sites of PLoS Medicine at Annals of Internal Medicine at and Epidemiology at Information on the STROBE Initiative is available at BMJ Open: first published as 0./bmjopen-0-0 on July 0. Downloaded from on 0 December 0 by guest. Protected by copyright.,, 0