WHOQOL-BREF among Singaporean Patients with Type II Diabetes Mellitus: What Does It Measure.
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Date
2014-06-11
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Abstract
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.
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Keywords
Diabetes mellitus, reliability, validity, health-related quality of life, quality of life, Singapore, Asia
Citation
Maudrene Tan Luor Shyuan, Tan Bautista Dianne Carrol, Hao Khoo Eric Yin, Konstadina Griva, Michelle New, Mohammad Amir, Seng Lee Yung, Jeannette Lee, Shyong Tai E, Lin Wee Hwee. WHOQOL-BREF among Singaporean Patients with Type II Diabetes Mellitus: What Does It Measure. British Journal of Medicine and Medical Research. 2014 June; 4(17): 3293-3316.