British Journal of Medicine and Medical Research, ISSN: 2231-0614,Vol.: 4, Issue.: 17 (11-20 June)
WHOQOL-BREF among Singaporean Patients with Type II Diabetes Mellitus: What Does It Measure?
Tan Luor Shyuan Maudrene1*, Bautista Dianne Carrol Tan2,3, Khoo Eric Yin Hao4, Griva Konstadina5, New Michelle4, Amir Mohammad5, Lee Yung Seng6,7,8, Lee Jeannette1, Tai E Shyong1,4 and Wee Hwee Lin9* 1Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
2Center for Quantitative Medicine, Duke NUS Graduate Medical School, Singapore.
3Singapore Clinical Research Institute, Singapore.
4Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
5Department of Psychology, National University of Singapore, Singapore.
6Department of Paediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
7KTP-National University Children's Medical Institute, National University Hospital, Singapore.
8Singapore Institute for Clinical Sciences, A*STAR, Singapore.
9Department of Pharmacy, National University of Singapore, Singapore.
Tan Luor Shyuan Maudrene1*, Bautista Dianne Carrol Tan2,3, Khoo Eric Yin Hao4, Griva Konstadina5, New Michelle4, Amir Mohammad5, Lee Yung Seng6,7,8, Lee Jeannette1, Tai E Shyong1,4 and Wee Hwee Lin9*
1Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
(3) Boonhow Chew, Universiti Putra Malaysia, Malaysia.
Complete Peer review History: http://www.sciencedomain.org/review-history/4105
Aims: Health-related quality of life (HRQoL) of Type 2 diabetes mellitus (T2DM) is a growing concern globally given the increase in T2DM prevalence. Generic HRQoL instruments are important to allow cross-cultural, cross-population and cross-study comparisons. The short version of the World Health Organization Quality of Life (WHOQOL-BREF) questionnaire is a widely used generic questionnaire. Hence, we aimed to evaluate the psychometric properties of the WHOQOL-BREF among patients with T2DM in Singapore.
Study Design: Patients at a diabetes outpatient specialist clinic in Singapore were recruited via convenience sampling. Classical Test Theory methods were used to evaluate data quality, scaling assumptions, targeting, internal consistency reliability and construct validity (structural, convergent and discriminant) and criterion validity using HbA1c control (good versus poor). Principal Component Analyses (PCA) and Confirmatory Factory Analyses (CFA) were performed to assess unidimensionality (domain-level) as well as conformity with the original four-factor structure. Exploratory Factor Analysis (EFA) was done if CFA indicated lack of fit.
Results: 212 subjects were analyzed of whom 50% were Chinese, 28% Indians, 11% Malays and 10% others. 63% were males with mean (SD) age 45.8 (11.9) years. Data quality was superior, scaling assumptions were met, targeting was satisfactory and internal consistency was achieved. PCAs were compatible with unidimensionality, except in the Physical domain. Domain level CFA indicated that unidimensionality had poor fit and overall CFA did not support the original 4-factor structure. EFA runs showed that the Physical and Environment domains overlapped while the Social and Psychological domains could not be recovered. Therefore construct (structural) validity was not established. Criterion validity was not achieved as all domains could not discriminate between those with good versus poor HbA1c control.
Conclusion: Construct and criterion validity of WHOQOL-BREF posed some concerns. Thus, we recommend that an adequately-powered random sample of T2DM patients in Singapore be studied to confirm the findings of our study.
Diabetes mellitus; reliability; validity; health-related quality of life; quality of life; Singapore; Asia.
Full Article - PDF Page 3293-3316
DOI : 10.9734/BJMMR/2014/9054Review History Comments