INTRODUCTION
At present, the improvement in the quality of life of the population has become at the forefront of national policies globally. With the growth of population in Vietnam growing speedily, there are many challenges. Although the average age in Vietnam is higher than other countries of similar income levels but the quality of the population is below average. Vietnam is ranked 105 of 117 in terms of the Human Development Index (HDI).1,2 While the average life expectancy was relatively high at 72.8 years in 2009, but the average number of healthy life years of the Vietnam was low at 58.2 years.3
Within the past few decades, an increase in the number of population has posed a challenges worldwide, especially elderly increasing. In the middle of 20th century, only 4 percent of the population in developing countries was 65 years old and above.4 The proportion of elderly people in Vietnam increased rapidly. The percentage of citizens aged 60 and above increased from 6.7 percent in 1979 to 9.2 percent in 2009. The majority of people in Vietnam lives in rural areas-72.9 percent - with inconvenient living conditions.5 Parallel with the increasing of the number of elderly, the crisis in national economic combine with lacking of standard living conditions, the quality of life of Vietnamese population was affected.
In Vietnam, there has been some research on the quality of life, but most of them focus on the health, disease patterns, and health management only. There is little in-depth research regarding quality of life of the population in Vietnam. The purpose of this study is to determine the status of health-related quality of life outcome of population in Vietnam through evaluation instruments.
METHODS
The systematic searching was conducted on November 15th, 2015, in MEDLINE (using PubMed), Scopus (using www.scopus.com), Google Scholar (using www.scholar.google.com), and Cochrance (using www. cochrance.org) to identify all articles of health-related quality of life outcome published from previous to November, 2015. We aimed to identify all articles using quality of life or health-related quality of life instruments as a questionnaire in their researches to make a comparison these studies together.
The search method consisted of search terms for systematic reviews, search terms for measurement instrument, and a validated methodological search filter for measurement properties.6 References of included articles were checked again for additional relevant studies in case they are necessary. The boolean word (AND, OR), field specification (Title, Abstract, All fields), checking duplication, comparison between articles and criteria also were used as technique in searching progress. The full syntax was use in this study is: (((((((Health-related quality of life) OR HRQOL) OR HRQoL) OR HRQL)) OR (((Quality of Life) OR QOL) OR QoL))) AND Viet*[Title/Abstract].
The following inclusion criteria were used in studies on quality of life or health-related quality of life area were conducted in population in Vietnam. These studies were used quality of life or health-related quality of life questionnaire as an instrument in their researches. On the other hand, the exclusion criteria were used:1 the studies were conducted in Vietnamese population but they do not evaluate the quality of life or health-related quality of life of human;2 the quality of life or health-related quality of life Vietnamese population living overseas were not excepted;3 the publications were published on non-English journals also were not included.
The results of the study were compared together, which used the similar instrument to assessment the quality of life or health-related quality of life. We concern about the quality of life of population; what instrument is used; when the study was conducted; and what function the authors were mentioned. The searching progress based on the abstracts and article selection is provided in Figure 1.
RESULTS
The review was conducted on November 2015. Through the searching syntax as above, we apply it into searching progress in the databases. 168 articles were identified from PubMed database and 328 articles were identified from Scopus by search terms. Besides that, 22 articles in Cochrane and 72 articles in Google Scholar also were found.
To combine these studies together, 56 articles were duplicated. In there, 504 articles were excluded because of criteria selection. They are not in quality of life or health-related quality of life (439 articles); they did not conduct in Vietnam (64 articles) and four articles were written by Japanese and Korean. In conclusion, twenty-seven articles were reviewed based on the review progress.
The first quality of life article were conducted in Vietnam start from 1999.7 We can see it as a background or evidence-based to develop the method to evaluate quality of life of human living in Vietnam. But for a long time, the quality of life or health-related quality of life is not concerned in Vietnam, so no article about quality of life is conducted as we can see in the Table 1. From 2005, this topic was concerned again with three articles.8-10 And the studies related with this topic were being conducted continuously. 2012 is the year when most of articles were conducted (ten articles).11-18
Table 1:
Summary the articles through year by year
| Years | 1999 | 2005 | 2008 | 2010 | 2011 | 2012 | 2014 | 2015 |
|---|---|---|---|---|---|---|---|---|
| Number of publications | 1 | 3 | 1 | 3 | 2 | 10 | 5 | 2 |
| Participants | Under 200 | 200-400 | Over 1000 | |||||
| Number of publications | 3 | 9 | 15 | |||||
| Target samples | HIV patients | Elderly | Others | |||||
| Number of publications | 8 | 10 | 9 |
The number of participant also is calculated in this review in. Over a half of articles were conducted with the subjects more than 1000 people, nine articles were conduct with around from 200 to 400 participants.
For other articles, the number of participants less than 200 people. On the other hand, the target subjects of the studies is limited in two main group as HIV patients and elderly. For the other subject, it only focuses on minority subject in the whole population.
Among these articles, many instruments were used to evaluate the quality of life or health-related quality of life of population living in Vietnam. All instruments are listed in Table 2. WHOQOL questionnaire and EQ-5D are instruments were used to much, 13 times7,8,10-14,16,18-20 and six time,17,21-25 respectively. Besides that, some other instruments also are used, such as: SF questionnaire,26,27 Vision-related Quality of life-VRQOL questionnaire,27-29 Adolescent Duke Health Profile-ADHP questionnaire.8,21
Table 2:
Summary the instruments are used in articles
In this review, the studies which used EQ-5D questionnaire as an instrument in their researches were selected. This instrument is selected because it can convert into the utility index–one of key factor to calculate the quality of life index, also in calculating the cost of utility. The results of these articles using this instrument are summarized in the Table 3.
Among six articles, only two articles mention in quality of life index. In these papers, one paper mentions the quality of life of elderly living in rural area in Northern Vietnam with 0.876 (rank from 0 – 1.000).24 The other one evaluate the quality of life of HIV patient with 0.65.17 Other articles are use it as an application into costing studies.
DISCUSSION
Through this review, the quality of life or health-related quality of life studies of population in Vietnam were conducted for a long time, and almost in last five years. The quality of life problem is more concern than before when the economic conditions in each family also better than before. Besides that, when the researches are conducted for long time, it is an advantage condition to compare and evaluation the change and the trend in the quality of life or health-related quality of life of Vietnamese population.
Because of orientation establish utility score, we concern about the status of using EQ-5D as an instruments to transfer into utility. Four in five researches use old version of EQ-5D with three levels. Hoi Le V. et al24 indicated this version has limitation on described more specific than new version with five levels. Besides that, they had a comparison between EQ-5D and Visual Analogue Scale (VAS),17 between EQ-5D and Duke Health Profile (DHP) questionnaire.21 In these articles, they showed the appropriate of using EQ-5D questionnaire than using other instruments to evaluation quality of life or health-related quality of life in Vietnamese context.
Table 3:
Summary the results of articles using EQ-5D questionnaire
On the other hand, we also meet some limitations when conducting the research. There are many instruments are used to evaluate the quality of life of Vietnamese population and we do not have any guideline to convert or equivalent these score together. So, we cannot compare these quality of life index together. Although the quality of life indexes are high but they are not comprehensive reflection the quality of life of whole population; the target samples only focus in some specific group as the elderly or HIV patients.
CONCLUSION
This review provides the overview about the status of research in quality of life or health-related quality of life area in Vietnamese population. The instruments were used in these articles are unification and lack of the research evaluating the quality of life or health-related quality of life in representative whole Vietnamese population. In next research, we can develop and apply more studies using EQ-5D to evaluate the quality of life of whole population to make evidence-based in whole country.
