Since December 1986, the Government provided to shift in political and economic policies, namely Doi moi (Renovation) as well as development strategy based on the conversion from a centrally planned economy to form of market socialism. From a domestic perspective, such renovation appears as a potential opportunity which serves the purpose of opening and varying the market of healthcare system.1 As regards the survey results conducted by The Vietnamese National Population Census in 2012, the population of Vietnam was 88.78 million people, of which nearly 60% were expected to benefit from health insurance by the year 2010 thanks to the high percentage of 92.73% in the contribution of out-of-pocket spending toward financing healthcare.2
Economic evaluation was defined as “the comparative analysis of alternative courses of action in terms of both their costs and consequences” by Drummond.3 It implicated the difference between economic evaluation and other assessment is the identification, appraisal and collation of costs and consequences. However, the characteristics of the outcomes may distinguish remarkable based on the type of economic evaluation, for example, cost minimization analysis (CMA), cost effectiveness analysis (CEA), cost utility analysis (CUA), cost benefit analysis (CBA), programme budgeting and marginal analysis, discounting, sensitivity analysis in health economic evaluation (HEE).4 Nowadays, economic evaluation studies play a major role in amelioration decisions about the apportion of human resources in healthcare. On the other hand, with the objective to evaluate the quality of economic evaluation results, it is necessary that researchers, policy makers and healthcare providers are to be informed with the appropriate methods used in the studies, the valid results and to the ability settings studies be applied.5 Economic evaluation of drugs, medical devices, services and interventions is a useful tool for assessing important decisions regarding the optimal utilization of scarce resources. On the other hand, it is essential to make efficient and effective use of the limited resources to reduce the burden on the population.6 Formerly, it was infeasible to find studies with a comprehensive view about the characteristics and the quality of pharmaco-economic and health economic studies carried out in Vietnam. Meanwhile, there have been studies that evaluated the trends and the quality of health economic implemented studies in India6, Bangladesh7, Thailand8, Zimbabwe9, Nigeria10, Iran11, and South Africa.12
Nevertheless, the recent years have witnessed a rapid increase in numbers of economic evaluation studies of health programs and only economic evaluations with high quality are used to assist the decision makers. Until now, despite the suggestion of many published methodological guidelines for economic evaluation that results of reported formats are to be presented in several countries, Vietnam has yet to build a national guideline to evaluate the quality of pharmaco-economic and health economic evaluation studies. Nevertheless, there was prediction of methodological weaknesses and possible lack of standardization. The aim of this study is to have an overview the tendency and assess the quality of HEE studies conducted in Vietnam between 2003 and 2016.
MATERIALS AND METHODS
This study was designed as a systematic review following the PRISMA guidelines.13 It was scoped in publication period of 2003 and 2016 in international journals.
Strategy of exploration
The literature review search was updated in June 2015 with citations from pharmaco-economic and health economic evaluation conducted in Vietnam between 2003 and 2016. The database of MEDLINE, SCIENCE DIRECT, COCHRANE LIBRARY and GOOGLE SCHOLAR were chosen to search for scholarly articles and peer-reviewed publications, in which their contents matched the following keywords: ‘economic evaluation, ‘economic analysis’, ‘cost minimization’, ‘cost effectiveness’, ‘cost utility, ‘cost benefit, ‘Viet*. Meanwhile, considering of Science Direct databases, this review is used the builder to create our search such as ‘economic evaluation’ or ‘economic analysis’ or ‘cost minimization’ or ‘cost effectiveness’ or ‘cost utility’ or ‘cost benefit’ AND ‘Viet*’ with [Abstract, Title, Keywords], and the period of time from 2003 to 2016.
Inclusion and exclusion criteria
All publications were included if systematic review intends to categorize and comprise articles which included a pharmaco-economic and health economic evaluation of health or any relevant interventions in Vietnam. Published articles were considered to be studies with primary or secondary data. Moreover, economic evaluation studies were qualified should their publication language was English and the content was related to humans.
Nevertheless, exclusion was made in case of publications being editorial, review or methodological articles or not presenting both the costs and outcomes of a study. Rejection was also applied to studies which content did not have any connection to the health sector, were not implemented in humans and were not applied in the context of Vietnam. Later on, additional relevant studies were identified and considered via the search for references adapted from qualified articles, which only ceased when there were no more new articles to be found. All identified abstracts were reviewed by the first author. (See Figure 1.).
Evaluation of economic evaluation studies in healthcare
This study was analyzed and separated into two parts including general information section and quality of health economic evaluation section. In the former section, the economic evaluation literature and a review of the technical characteristics of the article including the following information: number of authors, training of primary author, country of residence of primary author, publication year, journal publishing said study, the journal’s origin (country where the journal is published). Furthermore, this study also explored types of costs including economic evaluation used in publications, the primary outcomes, study design, perspective considering if the foremost goal of any study was economic evaluation, and funding source. Regarding the latter section, there are two possible ways to assign the quality of health economic evaluation. The first method stated that qualities of reporting have adhered to particular methodological and reporting practices recommended by Drummond et al3,14 with six aspects including (1) clearly the study perspective, (2) description of comparator(s), (3) use of discounting methods in case of the costs and/or outcomes originating from a study with its times-pan being over 1 year, (4) report about the incremental cost-effectiveness ratio (ICER), (5) performance of uncertainty analysis, (6) disclose of funding sources. Secondly, the parameters of quality of studies were measured by data source in economic analyses.
RESULTS AND DISCUSSION
After a search conducted in June, 2015 which resulted in a removal of 74 papers of duplicates, a total of 1282 citations were identified, in which 1257 titles and/or abstracts were excluded by reviewers due to their incompetence to meet required criteria., also there were full-text reviews being rejected as their content was not related to the study question. The review unveiled that twenty-three full text publications were retrieved and identified.
See Figure 1 for flow chart for systematic literature search and evaluation of including publications.
General Characteristics of Included Studies
As statistics are shown, the total number of included studies from 2001 to 2015 was 23 which were the works of either Vietnamese or Foreign authors. In the years of 2001, 2005, 2008, 2014 and 2015 it was noticeable that there was only one study being published each year. Meanwhile, the years of 2009 and 2013 had the even number of 3 studies for each year. In 2011, the figure rose to 5 studies and in the final year of 2012 it was 7 studies, which was acknowledged as the highest rate of publication throughout the survey. In reference off 23 studies with various methodology and the subject of evaluation during a period of 15 years, it was concluded that the average number of publications per year was 1.53 (range from 0 to 7), and 100 percent of articles on health economic evaluations program in Vietnam were published in international journals. In term of the published articles, the major type of correspondent or first authors (n=11: 47.8%) were reported as Vietnamese people, and the other (n=12: 52.2%) was foreign authors. However, most of studies included collaboration with Vietnam institutions. (Table 1)
Table 1. The characteristic of health economic evaluation studies (n=23) in Vietnam
As can be seen from the Table 1, only two out of four methodologies applied for conducting research on health economic evaluation study including CEA and CUA studies. The number of cost-effectiveness analysis study (n=22: 95.7%) were the most frequently type and only one cost-benefit analysis study (n=1: 4.3%). Among the health and health-related interventions of studies, the characteristics of the interventions that were consisted of prevention interventions (n=11: 47.8%); diagnostic procedures (n=4: 14.7%), curative procedures (n=7: 30.4%), services deliveries (n=2: 8.2%). Vaccination, the methadone maintenance treatment (MMT) for HIV/AIDS patients studies were the most common study interventions with 11 articles. The perspective and study design of the economic evaluation publications were mentioned in (n=20: 87.0%) and (n=23: 100.0%), respectively. Out of 100 percent of publications in Vietnam, the type of economic evaluation articles were calculated based on the healthcare system perspective in (n=7: 30.5%), the societal perspective in (n=2: 8.7%) publications, the payer perspective in (n=3: 13.0%) publications, the provider perspective in one (n=1: 4.3%), the mixed various perspective (n=8: 34.8%), and not available (n=2: 8.7%). The most frequently method of study design is modeling (52.2%). Thus, the proportion of retrospective data analysis, modeling and Cohort study and randomized clinical trial publications are 26.1 percent, 4.3 percent, 17.4 percent, respectively. Microsoft Excel (n=8), TreeAge (n=3) were the most favorable softwares to be used to analyse data in the papers.
|CHARACTERISTICS OF INCLUDED STUDIES||N||%||CHARACTERISTICS OF INCLUDED STUDIES||N||%|
|The first author of affiliation||Language published|
|Data analysis by software||Type of data used|
|Microsoft Excel||8||34.8||Primary data||18||78.3|
|Not available||9||39.1||Type of journal|
|<= 1 year||9||39.1||Non-medical**||10||43.5|
|1 - <=5 years||8||34.8||Type of intervention|
|> 5 – <=10 years||2||8.7||Prevention interventions||11||47.9|
|Over 10 years||-||-||Diagnostic procedures||4||17.4|
|Not specified||4||17.4||Curative procedures||7||30.4|
|Methodology of health economic evaluation||Services deliveries||1||4.3|
|CEA||22||95.7||Type of study design|
|CBA||1||4.3||Modeling and Cohort study||6||26.1|
|Type of cost included ***||Randomized clinical trial||1||4.3|
|1 item||7||30.5||Retrospective data analysis||4||17.4|
|2 items||5||21.7||Type of sensitivity analysis|
|3 items||6||26.1||One-way analysis||2||8.7|
|Type of outcome||Probabilistic analysis||6||26.1|
|QALY/DALY, ICER||12||52.2||Mixed >=2 types||5||21.7|
|Type of perspective||N/a||2||8.7|
|Healthcare system||7||30.5||Disease categories|
|Payer||3||13.0||The methadone maintenance treatment||4||17.4|
|Mixed||8||34.8||Cleft clip and cleft palate surgical services||1||4.3|
|Type of correspondence or first author||Smoking||1||4.3|
|Primary funding resources||Evaluated CrAg prevalence screening strategy||1||4.3|
|Private non - profit organization||7||30.5||Postpartum hemorrhages||1||4.3|
|No funding||11||47.8||Brain metastasis||1||4.3|
|Included studies by authors and publication year|
|Vietnamese authors||Foreign authors|
|No.||Study (year)||Perspective specified||Description of comparator(s)||Used discounting||Calculated and reported ICER||Performed uncertainty analysis - Probabilistic sensitivity analysis (PSA)||Disclosed funding source|
|1||Phuc et al (2015) 15||✓||✓||✓||✓||✓ (PSA)||n/a|
|2||Dam et al (2014) 16||n/a||✓||✓||✓||✓ (PSA)||n/a|
|3||Lan et al (2013) 17||✓||✓||✓||✓||✓ (PSA)||✓|
|4||Rachel M. Smith et al (2013) 18||✓||✓||n/a||✓||✓ (PSA)||n/a|
|5||Chantal M.Morel et al (2013) 19||✓||✓||✓||n/a||✓ (PSA)||n/a|
|6||Hong et al (2012) 20||✓||✓||✓||✓||✓ (PSA)||✓|
|7||Bach Xuan Tran et al (2012) 21||✓||✓||n/a||✓||✓ (PSA)||n/a|
|8||W. Moon et al (2012) 22||✓||✓||✓||n/a||n/a||n/a|
|9||Bach Xuan Tran et al (2012) 23||✓||✓||✓||✓||✓ (PSA)||✓|
|10||Duong Vuong Anh et al(2012) 24||✓||✓||n/a||✓||✓ (PSA)||n/a|
|11||Hong-Anh T.Tu et al (2012) 25||✓||✓||✓||✓||✓ (PSA)||✓|
|12||Bach Xuan Tran et al (2012) 26||✓||✓||n/a||✓||✓ (PSA)||✓|
|13||Gerard J.Casey et al (2011) 27||✓||✓||✓||n/a||n/a||n/a|
|14||Hideki Higashi et al (2011) 28||✓||✓||✓||✓||✓ (PSA)||✓|
|15||Christine Poulos et al (2011) 29||n/a||✓||✓||n/a||✓ (PSA)||✓|
|16||A. Tyrell et al (2011) 30||n/a||✓||✓||n/a||✓ (PSA)||n/a|
|17||Duc Anh Ha et al (2011) 31||✓||✓||✓||✓||✓ (PSA)||✓|
|18||Vivien D Tsu et al (2009) 32||✓||✓||✓||✓||✓ (PSA)||✓|
|19||Aya Yajima et al (2009) 33||n/a||✓||n/a||n/a||✓ (PSA)||n/a|
|20||Sun-Young Kim et al (2009) 34||✓||✓||✓||✓||✓ (PSA)||✓|
|21||Jane J. Kim et al (2008) 35||✓||✓||✓||✓||✓ (PSA)||✓|
|22||Thea K. Fischer et al (2005) 36||✓||✓||✓||✓||✓ (PSA)||✓|
|23||Huong et al (2001) 37||✓||✓||n/a||n/a||n/a||n/a|
THE QUALITY OF INCLUDED STUDIES
Quality of reporting practice
Table 2. Articles evaluated checklist in this review (n= 23)
In the light of Drummond et al’s checklist, the assessment of methodological quality of economic evaluation of all articles was made.3,14 Table 2 shows the extent to which eighteen publications met the recommendation for reporting economic evaluations.
The economic evaluation’s viewpoint play a major role in determining which expenses and effectiveness should be coordinated closely in the study. However, four studies (82.61%) were not mentioned clearly in his systematic review. Performing sensitivity analysis is a matter of great importance to assess the lustiness of the results to changes in assumptions. Sixteen of the assessed articles performed probabilistic sensitivity. Furthermore, in consideration of the twenty-three studies, which revealed their discounting rate and reported ICER, have been applied in many studies; the using discounting rate was either 3% or 5%. Considering funding resources, there were 12 studies in which the authors declared their supporters.
Proportion of economic evaluation publications in Vietnam from 2003 to 2016
Table 1 shows the proportion of DALYs by major disease categories and the proportion of economic evaluation publications in Vietnam from 2003 to 2016. The most frequently investigated issues states were vaccination (26.1%), the methadone maintenance treatment (17.4%) and anemia (13.9%). Other issues state which account for 4.3% investigated include malaria, cleft clip and cleft palate surgical services, smoking, clonorchiasis, brain metastasis, cardiovascular disease, postpartum hemorrhages, evaluated CrAg prevalence screening strategy. The table highlights only one study (i.e. cardiovascular disease) that mentioned major disease categories in Vietnam.
The recent years (2009-2016) have experienced an increase in the number of articles, despite the fact that such statistics are still considered to be low compared to setting where EE used in policy decision making. However, other factors such as training, curriculums, and so on have an impact on increase in the quantity and quality of EE studies. The methodoligical issues of health economic evaluation studies in Vietnam context are composed of lack of caculation of an ICER, and limited use of discount rate with more one year servey. A report is marked as unqualified should it fail to indicate the the usefulness of economic assessment in policy decision- making
Limitation of this study
In the recent context of Vietnam, it is considered to be infeasible to find any national database for healthacre publications. Meanwhile, available literatures from international databases are published in English, which do not belong to categories, namely, abstract, conference proceedings, unpublished reports, Vietnam publications, master and Doctor of Philosophy theses, paper presented at the meeting or seminars. Furthermore, Viet researchers can perform many HEE studies - “grey literature”, and were not publised in journals.
This review of economic evaluation studies is considered to be pioneering to be conducted in the particular context of Vietnam. Moreover, this study helps to understand clearly the current situation and the urgent need for development of national methodological guideline for conducting and reporting economic evaluation in Vietnam. On the other hand, it is essential that the Ministry of Health develop a comprehensive and systematic methods for prioritizing topics in order to conduct future economic assessment in Vietnam by many different steps such as: set up standardization of guidelines, support education starting from undergraduate level to professional level.