RESUMO
OBJECTIVES: To test the psychometric properties of the EUROHIS-QOL 8-item index, a shortened version of the World Health Organization Quality of Life Instrument-Abbreviated Version (WHOQOL-BREF). METHODS: The sample consisted of 2359 subjects identified from primary care settings, with 1193 having a confirmed diagnosis of depression. Data came from six countries (Australia, Brazil, Israel, Russia, Spain, and the United States) involved in a large international study, the Longitudinal Investigation of Depression Outcomes. The structure of the EUROHIS-QOL 8-item index follows that of the WHOQOL-BREF assessment. Internal consistency was measured by using Cronbach's alpha. Convergent validity was assessed by using correlations with different measures for mental health (Symptom Checklist 90), physical health (self-evaluation), and quality of life (WHOQOL-BREF and short form 36 health survey). Discriminant group validity was assessed between diagnosed depressed and nondepressed patients. Differential item functioning and unidimensionality were analyzed by using Rasch analysis. Factor structure was assessed with structural equation modeling analyses. RESULTS: Internal consistency was acceptable (ranged between 0.72 and 0.81 across countries), and the index discriminated well between depression (t = 6.31-20.33; P < 0.001) across all countries. Correlations between the EUROHIS-QOL 8-item index and different measures--Symptom Checklist 90 (r = -0.42), physical health (r = -0.42), WHOQOL-BREF domains (r = 0.61-0.77), and short form 36 health survey (r = 0.58)--were all significant (P < 0.001). The index is unidimensional with desired item fit statistics. Two items ("daily living activities" and "enough money to meet your needs") had residuals exceeding 4. Differential item functioning was observed with general quality of life, general health, relationships, and home items for age. A common one-factor structure with acceptable fit was identified in three out of six countries (comparative fit index = 0.85, root mean square error of approximation = 0.11). CONCLUSIONS: The EUROHIS-QOL 8-item index showed acceptable cross-cultural performance and a satisfactory discriminant validity and would be a useful measure to include in studies to assess treatment effectiveness.
Assuntos
Psicometria/instrumentação , Qualidade de Vida , Inquéritos e Questionários/normas , Adulto , Transtorno Depressivo Maior/epidemiologia , Países Desenvolvidos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Organização Mundial da SaúdeRESUMO
BACKGROUND: The Rasch model prescribes procedures to ensure that a scale constructed from multiple items conforms to fundamental requirements of interval scales of measurement. OBJECTIVE: To test the Rasch properties of the domains of the World Health Organization Quality of Life Instrument-abbreviated version (WHOQOL-BREF) in depressed patients from primary care settings. DESIGN: Cross-sectional, cross-national study. SETTING: Primary care. PATIENTS: The sample consisted of 1193 patients having a confirmed diagnosis of depression from 6 countries (Australia, Brazil, Israel, Russia, Spain, and the United States) involved in the Longitudinal Investigation of Depression Outcomes (LIDO) study. MEASUREMENTS: The Composite International Diagnostic Interview (CIDI) diagnosed depression, whereas the Center for Epidemiological Studies Depression Scale (CES-D) assessed severity of depression. The WHOQOL-BREF measured generic quality of life (QOL). RESULTS: Three of the 4 WHOQOL-BREF domains (physical, psychological, and environment) conform to the Rasch model expectations, following adjustments required mainly because of individual item misfit or differential item functioning (DIF) due to age or country. The social domain showed relatively poor psychometric properties, as observed in previous studies. CONCLUSIONS: The Rasch analysis demonstrated that, with some modifications, all domains of the WHOQOL-BREF, except for the social domain, provide an interval scale measure of generic subjective QOL in the context of depressed primary care patients in 6 countries worldwide.
Assuntos
Comparação Transcultural , Depressão , Pacientes/psicologia , Atenção Primária à Saúde , Inquéritos e Questionários , Adulto , Feminino , Nível de Saúde , Humanos , Internacionalidade , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Psicometria , Qualidade de Vida , Adulto JovemRESUMO
BACKGROUND: Previous studies found that depression is associated with a broad impairment in quality of life (QOL). This finding might be associated to a measurement overlap. METHODS: The objective of this study was to verify whether the items of the World Health Organization Quality of Life Instrument-Abbreviated version (WHOQOL-BREF), a measure of generic QOL, are invariant among patients having a current major depressive episode who come from primary care services. We investigated data from primary care services from the 6 countries (Australia, Brazil, Israel, Russia, Spain, and the United States) involved in the baseline sample of the Longitudinal Investigation of Depression Outcomes. The Rasch model was used to analyze items exhibiting differential item functioning (DIF) as a way of assessing invariance in relation to a depression factor defined by the diagnosis of depression using the Composite International Diagnostic Interview. In addition, the Center for Epidemiological Studies-Depression Scale (CES-D) score was correlated with the item and domain scores of the WHOQOL-BREF using the Pearson coefficient. RESULTS: The sample consisted of 2359 subjects, of which 1193 had a confirmed diagnosis of a current major depressive episode. Of the 26 items of the WHOQOL-BREF, 11 showed DIF due to the depression factor, and the physical domain presented more items displaying DIF. All Pearson coefficients between the WHOQOL-BREF item and domain scores and the CES-D score were weak and moderate (r = -0.13 to r = 0.43). CONCLUSIONS: Our findings indicate that most WHOQOL-BREF items do not exhibit DIF for a current major depressive episode and the variance associated with depression in this generic QOL measure is restricted to some facets of this construct. Thus, we recommend this restricted adjustment for depression in future analyses of this measure. Furthermore, our study indicates that researchers must measure QOL regardless of depression severity.
Assuntos
Transtorno Depressivo Maior/psicologia , Qualidade de Vida/psicologia , Adulto , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Escalas de Graduação PsiquiátricaRESUMO
BACKGROUND: Aging has determined a demographic shift in the world, which is considered a major societal achievement, and a challenge. Aging is primarily a subjective experience, shaped by factors such as gender and culture. There is a lack of instruments to assess attitudes to aging adequately. In addition, there is no instrument developed or validated in developing region contexts, so that the particularities of ageing in these areas are not included in the measures available. This paper aims to develop and validate a reliable attitude to aging instrument by combining classical psychometric approach and Rasch analysis. METHODS: Pilot study and field trial are described in details. Statistical analysis included classic psychometric theory (EFA and CFA) and Rasch measurement model. The latter was applied to examine unidimensionality, response scale and item fit. RESULTS: Sample was composed of 424 Brazilian old adults, which was compared to an international sample (n = 5238). The final instrument shows excellent psychometric performance (discriminant validity, confirmatory factor analysis and Rasch fit statistics). Rasch analysis indicated that modifications in the response scale and item deletions improved the initial solution derived from the classic approach. CONCLUSION: The combination of classic and modern psychometric theories in a complementary way is fruitful for development and validation of instruments. The construction of a reliable Brazilian Attitudes to Aging Questionnaire is important for assessing cultural specificities of aging in a transcultural perspective and can be applied in international cross-cultural investigations running less risk of cultural bias.