Xavier Badia

A model of equivalence in the cultural adaptation of HRQoL instruments: the universalist approach

The health-related quality of life (HRQoL) literature presents a confused picture of what ‘equivalence’ in the cross-cultural use of HRQoL questionnaires means and how it can be assessed. Much of this confusion can be attributed to the ‘absolutist’ approach to the cross-cultural adaptation of HRQoL questionnaires. The purpose of this paper is to provide a model of equivalence from a universalist perspective and to link this to the translation and adaptation of HRQoL questionnaires. The model evolved from reviews of the HRQoL and other literatures, interviews and discussions with researchers working in HRQoL and related areas and practical experience in the adaptation and development of HRQoL instruments. The model incorporates six key types of equivalence. For each type of equivalence the paper provides a definition, proposes various strategies for examining whether and how types of equivalence can be achieved, illustrates the relationships between them and suggests the order in which they should be tested. The principal conclusions are: (1) that a universalist approach to the cross-cultural adaptation of HRQoL instruments requires that six types of equivalence be taken into account; (2) that these are sufficient to describe and explain the nature of the cross-cultural adaptation process; (3) that this approach requires careful qualitative research in target cultures, particularly in the assessment of conceptual equivalence; and (4) that this qualitative work will provide information which will be fundamental in deciding whether to adapt an existing instrument and which instrument to adapt. It should also result in a more sensitive adaptation of existing instruments and provide valuable information for interpreting the results obtained using HRQoL Instruments in the target culture.

'Equivalence' and the translation and adaptation of health-related quality of life questionnaires.

The increasing use of health-related quality of life (HRQOL) questionnaires in multinational studies has resulted in the translation of many existing measures. Guidelines for translation have been published, and there has been some discussion of how to achieve and assess equivalence between source and target questionnaires. Our reading in this area had led us, however, to the conclusion that different types of equivalence were not clearly defined, and that a theoretical framework for equivalence was lacking. To confirm this we reviewed definitions of equivalence in the HRQOL literature on the use of generic questionnaires in multicultural settings. The literature review revealed: definitions of 19 different types of equivalence; vague or conflicting definitions, particularly in the case of conceptual equivalence; and the use of many redundant terms. We discuss these findings in the light of a framework adapted from cross-cultural psychology for describing three different orientations to cross-cultural research: absolutism, universalism and relativism. We suggest that the HRQOL field has generally adopted an absolutist approach and that this may account for some of the confusion in this area. We conclude by suggesting that there is an urgent need for a standardized terminology within the HRQOL field, by offering a standard definition of conceptual equivalence, and by suggesting that the adoption of a universalist orientation would require substantial changes to guidelines and more empirical work on the conceptualization of HRQOL in different cultures.

A Comparison of United Kingdom and Spanish General Population Time Trade-off Values for EQ-5D Health States:

Few studies have compared preference values for health states obtained in different countries. The present study compared Spanish and United Kingdom (UK) time trade-off values for EuroQol-5D health states. The same preference elicitation protocol was followed in both countries. Differences in values for 43 health states rated directly were analyzed using t tests, and regression coefficients generated by random effects modeling were compared by aggregating the 2 value sets and using dummy variables to analyze country effect by dimension and level of severity. For the milder health states, Spanish and UK value assignation was similar; for intermediate health states, Spanish values were both higher and lower than UK values, whereas for health states worse than death, UK values were generally higher than Spanish values. There were statistically significant differences (P < 0.01) in values for 34.9% of health states rated directly, and some preference reversals between countries. UK raters ascribed greater importance to dimensions of pain/discomfort and anxiety/depression, whereas Spanish raters placed more importance on functional dimensions of mobility and self-care. Further analysis is required to determine how these differences affect cost-effectiveness and cost-utility analyses.

Development of the EQ-5D-Y: a child-friendly version of the EQ-5D

PurposeTo develop a self-report version of the EQ-5D for younger respondents, named the EQ-5D-Y (Youth); to test its comprehensibility for children and adolescents and to compare results obtained using the standard adult EQ-5D and the EQ-5D-Y.MethodsAn international task force revised the content of EQ-5D and wording to ensure relevance and clarity for young respondents. Children’s and adolescents’ understanding of the EQ-5D-Y was tested in cognitive interviews after the instrument was translated into German, Italian, Spanish and Swedish. Differences between the EQ-5D and the EQ-5D-Y regarding frequencies of reported problems were investigated in Germany, Spain and South Africa.ResultsThe content of the EQ-5D dimensions proved to be appropriate for the measurement of HRQOL in young respondents. The wording of the questionnaire had to be adapted which led to small changes in the meaning of some items and answer options. The adapted EQ-5D-Y was satisfactorily understood by children and adolescents in different countries. It was better accepted and proved more feasible than the EQ-5D. The administration of the EQ-5D and of the EQ-5D-Y causes differences in frequencies of reported problems.ConclusionsThe newly developed EQ-5D-Y is a useful tool to measure HRQOL in young people in an age-appropriate manner.

Using the EuroQol 5-D in the Catalan General Population: Feasibility and Construct Validity

Spanish and Catalan versions of the EuroQol 5-D (EQ-5D) were included in the Catalan Health Interview Survey (CHIS) and administered to a randomly selected cross-section of 12,245 individuals from the Catalan general population. This paper analyses the feasibility, convergent validity and construct validity of three parts of the EQ-5D (the descriptive system, the visual analogue scale (VAS) and the Spanish tariff) using the results obtained in the CHIS. The feasibility was assessed by the number of missing responses. The convergent validity was based on the correlations between the EQ-5D scores and the scores on the General Health Questionnaire (GHQ) and on an index of self-perceived overall health. The construct validity was assessed by analysing the degree to which lower scores on the EQ-5D correlated positively with increasing age, being female, being in a lower social class or having a lower level of education and with increasing levels of disability, co-morbidity, restricted activity, mental health problems and poor self-perceived health. A low number of missing responses on the descriptive system and the VAS (1.5%) indicated a high level of acceptance. A marked ceiling effect was found, with 67% of the sample reporting no problem in any EQ dimension. The convergent validity with the GHQ was generally low, though moderate on the mood dimension. Self-perceived overall health correlated moderately to strongly with the mean VAS and tariff values. The positive correlations between lower scores on all three elements of the EQ-5D and increasing age, increasing levels of disability, co-morbidity, restricted activity, mental health problems and poor self-perceived health provide some evidence of the instruments construct validity, as does the fact that women reported more problems than men. Multivariate analyses using the VAS and tariff values as dependent variables and all of the sociodemographic and health variables as independent variables reached R2 values of 0.45 and 0.81, respectively. The Spanish and Catalan versions of the EQ-5D have proved to be feasible and valid for use in health interview surveys.

Influence of inflammatory bowel disease on different dimensions of quality of life.

Objective To establish the impairment of different dimensions of quality of life in inflammatory bowel disease (IBD). Design Prospective observational study. Participants 289 patients [160 with ulcerative colitis (UC) and 129 with Crohns disease (CD)]. Measures Health-related quality of life was assessed by means of the Inflammatory Bowel Disease Questionnaire (IBDQ) and the Psychological General Well Being Index (PGWBI). Results In active IBD, all dimensions of the quality of life scored significantly lower than in inactive IBD, indicating a poor quality of life. Social impairment was the least impaired dimension of the IBDQ in active UC and CD, compared with digestive and systemic symptoms. In inactive IBD, the systemic symptoms domain received the lowest score (P < 0.01). In a subgroup of 22 patients studied before and after remission, emotional function was the most impaired dimension after achieving remission. The Psychological General Well Being Index was significantly impaired in active UC [78.5 (range 64–89)] and CD [76.5 (range 69–97)] relative inactive IBD [104 (range 93–111)] vs 106 (95–113), respectively;P < 0.05]. Conclusions Quality of life is impaired in IBD. During relapse, clinicians should pay attention to digestive symptoms and psychological distress. In remission, they should be sensitive to systemic symptoms.

Validación de las versiones en español de la Montgomery-Asberg Depression Rating Scale y la Hamilton Anxiety Rating Scale para la evaluación de la depresión y de la ansiedad

Fundamento Los trastornos del estado de animo (TEA) y los trastornos de ansiedad (TA) constituyenlas alteraciones psiquiatricas mas comunes en la poblacion general. En este estudio se han evaluado,por primera vez, las propiedades psicometricas de las versiones en espanol de la Montgomery-AsbergDepression Rating Scale (MADRS) y la Hamilton Anxiety Rating Scale (HARS), ampliamente utilizadasen la practica asistencial y en investigacion clinica. Pacientes y metodo Se diseno un estudio de cohortes, observacional, prospectivo y multicentrico enpacientes con TEA o TA, clinicamente estables o inestables. Las escalas se administraron en la visitade inclusion en el estudio y en una segunda visita realizada a la semana .en el caso de pacientes estables.o dos meses despues –en pacientes inestables–. Se evaluaron la estructura factorial, la validez(convergente y discriminante), la fiabilidad (consistencia interna, estabilidad temporal y entre observadores)y la sensibilidad al cambio de ambas escalas. Resultados Se incluyo a 108 pacientes con TEA y a 106 pacientes con TA en 10 centros de asistenciapsiquiatrica con amplia distribucion geografica. Ambas escalas presentaron una adecuada: a) validezdiscriminante (MADRS/HARS-Impresion Clinica Global de Gravedad: p < 0,001); b) validez convergente(MADRS-Hamilton Depression Rating Scale: p < 0,05 y 0,01, respectivamente;MADRS/HARS-EuroQoL 5D: p < 0,05; HARS-State Trait Anxiety Inventory: p < 0,05); c) consistenciainterna (α de Cronbach: MADRS = 0,88; HARS = 0,89); d) fiabilidad test-retest y entre observadores(coeficiente de correlacion intraclase: MADRS = 0,94 y 0,98, respectivamente; HARS = 0,92 y0,92), y e) sensibilidad al cambio (tamano del efecto: MADRS = 2,05; HARS = 1,36). Conclusiones Las versiones en espanol de la MADRS y de la HARS presentan buenas propiedades psicometricas,similares a las de las escalas originales, por lo que resultan apropiadas para su uso en lapractica asistencial y en investigacion clinica en Espana.

Health related quality of life (HRQOL) of kidney transplanted patients: variables that influence it

The incidence and prevalence of patients on renal replacement therapy (RRT) who receive a renal transplant are continuously increasing in Spain. At the moment, they are the main group of end‐stage renal disease (ESRD) patients in our region (60% of total RRT patients). The aim of the present study was to assess the health related quality of life (HRQOL) of kidney transplanted patients of our region, and to identify socio‐demographic and clinical variables that influence it. The intention was also to compare the HRQOL of these patients with that of chronic haemodialysis (HD) patients and of the general population. 
Methods. Two hundred and ten kidney transplanted patients and 170 HD patients were evaluated using the Karnofsky performance scale (KPS), sickness impact profile (SIP), and SF‐36 Health Survey (SF‐36). Socio‐demographic and clinical data, including a comorbidity index (CI), were also collected. To compare our patients with the general population we used SF‐36 mean scores from an aleatory sample taken from our region. 
Results. Transplant patients had lower mean scores on SIP dimensions and higher scores on SF‐36 dimensions than chronic HD patients. In transplant patients, we found significant differences on SIP and SF‐36 scores in gender, educational level, haematocrite and haemoglobin, CI, time since transplantation, and KPS. 
Conclusions. The HRQOL of transplant patients is clearly better than that of chronic HD patients and similar to that of the general population. Differences in the HRQOL within transplant patients did not appear to be as a result of patients age, but rather it would appear to be a consequence of gender, analytic figures, CI, KPS score, time with transplant, and educational level.

Feasibility, validity and test-retest reliability of scaling methods for health states: the visual analogue scale and the time trade-off.

The feasibility, validity and reliability of the Time Trade-Off (TTO) and Visual Analogue Scale (VAS) methods in obtaining preference values for health states were compared in a random sample of the Spanish population (n = 294). Respondents valued 43 EuroQol-5D health states in face-to-face interviews. Convergent validity was assessed by examining the relationship between values, and the effect of sociodemographic and health variables on values was used as a means of assessing construct validity. Test–retest reliability was analysed in a sub-group of 50 respondents, using the intraclass correlation coefficient (ICC) and generalisability theory. Rates of non-response and missing data were low on both methods, though the VAS took considerably less time to administer. VAS and TTO values correlated highly (r = 0.92), though there were differences in the ordering of health states between methods, and in the number of health states rated worse than death. VAS values were compressed into a considerably smaller valuation space than TTO values. Respondents in higher educational categories assigned higher TTO values to 12 health states. Mean ICCs (95 CI) at individual level were 0.90 (0.88–0.92) and 0.84 (0.81–0.87) for the VAS and TTO, respectively. Generalisability analysis showed variance due to time to be 0 for both methods. In conclusion, the VAS was more feasible and slightly more reliable than the TTO, whilst doubt can be cast on the degree of convergent validity existing between the two methods. The compression of VAS values means that the TTO is likely to discriminate better between health states, and it may have greater construct validity if results from larger samples confirm that there are genuine differences between sociodemographic sub-groups.

Clinical patterns over time in irritable bowel syndrome: symptom instability and severity variability.

OBJECTIVES:The clinical course of irritable bowel syndrome (IBS) remains poorly known. In 209 IBS patients meeting Rome II criteria (137 females and 72 males) we evaluated: (1) changes in frequency and intensity of abdominal pain/discomfort, abnormal number of bowel movements, loose or watery stools, defecatory urgency, hard or lumpy stools, straining during bowel movements, and feeling of incomplete evacuation); (2) use of resources, HRQoL, and psychological well being.METHODS:Observational, prospective, multicenter study. Symptoms were registered in a diary over two 28-day periods with an interval of 4 wk; direct resource use and indirect costs were noted weekly. Three HRQoL questionnaires were administered.RESULTS:High-intensity symptoms were present on more than 50% of the days. Sixty-one percent were classified in the same IBS subtype on both occasions (κ= 0.48), while 49% had the same symptom predominance and intensity (κ= 0.40). The greatest instability was observed among diarrhea (D-IBS) and constipation (C-IBS) subtypes: only 46% and 51% remained in the same pattern with a tendency to shift to alternating diarrhea/constipation subtype (A-IBS); however, practically no patient changed from D-IBS to C-IBS, or vice versa. The most reliable symptom characteristic was frequency, followed by intensity and number of episodes. Symptom frequency and intensity were directly related to resource use and HRQoL impairment.CONCLUSIONS:IBS symptoms are instable over time and variables in intensity. Many patients with D-IBS or C-IBS move to A-IBS; however, shift from D-IBS to C-IBS, or vice versa, is very infrequent.