Health services - Research lines Jordi Alonso

The International health-related Quality of life Outcomes Database (IQOD)

Research Team: Montse Ferrer, Jordi Alonso, Olatz Garin, Àngels Pont

The International health-related Quality of life Outcomes Database (IQOD) Group defines as general objective to develop a database of HRQL item responses, clinical and socio-demographic data from multiple sources of HRQL studies conducted throughout Europe; with the purpose of evaluating the psychometric properties of linguistically validated versions of three HRLQ instruments . The selected instruments were: The Women’s Health Questionnaire (WHQ), the Psychological General Well-being Index (PGWB), and the Minnesota Living with Heart Failure Questionnaire (MLHFQ). Each of these instruments was selected for the IQOD project because of favourable reports of its reliability and validity, its linguistic adaptation into multiple European languages, and its extensive use throughout Europe and the US. However, the metric properties of these different versions have not been cross-culturally evaluated. The MLHFQ contains 2 domains (physical and emotional) with 8 and 5 items.

General Aim: the purpose of this study is to apply psychometric methods to examine the equivalence of the most commonly used instrument for heart failure impairment, the MLHFQ, across 21 countries; and confirm its structure.

Methods: Health Related Quality of Life, clinical and socio-demographical data from 8 studies were pooled (n=2780 patients with heart failure). A Confirmatory Factor Analysis (CFA) has been conducted to evaluate the structure and dimensionality of the questionnaire. Furthermore, its metric properties have been compared across countries.

Results: The CFA within each country provided significant factor loadings for all the items. The goodness of fit CFI and NNFI indices were acceptable (>0.90). In contrast, the Root Mean Square Error was only acceptable for Canada and Germany, it ranged within 0.066-0.146 for the rest of countries. The factor loading equality across the 8 countries was significant (p < 0.0001). Regarding the dimensions’ metric properties, Cronbach’s alpha coefficient was above 0.7 for all countries and scales. No difference was shown across countries in the scale score means, and mean differences between patients in NYHA class I-II and III-IV followed the expected pattern.

Conclusions: In spite of the excellent reliability and validity showed by scales across versions, further research on the MLHFQ structure is needed.

Status: Dissemination of the results

Funding: EC ALRI-CT-2000-00551; SAF2002-11009-E; DURSI-GENCAT 2005-SGR-00491