James Twiss

Can We Rely on the Dermatology Life Quality Index as a Measure of the Impact of Psoriasis or Atopic Dermatitis

The Dermatology Life Quality Index (DLQI) is a widely used health-related quality of life measure. However, little research has been conducted on its dimensionality. The objectives of the current study were to apply Rasch analysis to DLQI data to determine whether the scale is unidimensional, to assess its measurement properties, test the response format, and determine whether the measure exhibits differential item functioning (DIF) by disease (atopic dermatitis versus psoriasis), gender, or age group. The results show that there were several problems with the scale, including misfitting items, DIF by disease, age, and gender, disordered response thresholds, and inadequate measurement of patients with mild illness. As the DLQI did not benefit from the application of Rasch analysis in its development, it is argued that a new measure of disability related to dermatological disease is required. Such a measure should use a coherent measurement model and ensure that items are relevant to all potential respondents. The current use of the DLQI as a guide to treatment selection is of concern, given its inadequate measurement properties.

Translation and validation of non-English versions of the Ankylosing Spondylitis Quality of Life (ASQOL) questionnaire.

BackgroundThe Ankylosing Spondylitis Quality of Life (ASQOL) questionnaire is a unidimensional, disease-specific measure developed in the UK and the Netherlands. This study describes its adaptation into other languages.MethodsThe UK English ASQOL was translated into US English; Canadian French and English; French; German; Italian; Spanish; and Swedish (dual-panel methods). Cognitive debriefing interviews were conducted with AS patients. Psychometric/scaling properties were assessed using data from two Phase III studies of adalimumab. Baseline and Week-2 data were used to assess test-retest reliability. Validity was determined by correlation of ASQOL with SF-36 and BASFI and by discriminative ability of ASQOL based on disease severity. Item response theory (Rasch model) was used to test ASQOLs scaling properties.ResultsCognitive debriefing showed the new ASQOL versions to be clear, relevant and comprehensive. Sample sizes varied, but were sufficient for: psychometric/scaling assessment for US English and Canadian English; psychometric but not scaling analyses for German; and preliminary evidence of these properties for the remaining languages. Test-retest reliability and Cronbachs alpha coefficients were high: US English (0.85, 0.85), Canadian English (0.87, 0.86), and German (0.77, 0.79). Correlations of ASQOL with SF-36 and BASFI for US English, Canadian English, and German measures were moderate, but ASQOL discriminated between patients based on perceived disease severities (p < 0.01). Results were comparable for the other languages. US English and Canadian English exhibited fit to the Rasch model (non-significant p-values: 0.54, 0.68), confirming unidimensionality.ConclusionThe ASQOL was successfully translated into all eight languages. Psychometric properties were excellent for US English, Canadian English, and German, and extremely promising for the other languages.

International Development of the Patient-Reported Outcome Indices for Multiple Sclerosis (PRIMUS)

BACKGROUND The Patient-Reported Indices for Multiple Sclerosis (PRIMUS) comprises a suite of three scales for assessing symptoms, activity limitations, and quality of life in multiple sclerosis (MS). It was developed in the UK and has been shown to have excellent psychometric properties. This study describes the adaptation of eight language versions for Canadian English, Canadian French, French, German, Italian, Spanish, Swedish, and US English. METHODS The PRIMUS was translated using the dual-panel process. Cognitive debriefing interviews conducted with MS patients assessed face and content validity. Psychometric and scaling properties were assessed via a two-administration postal survey conducted in each country involving the PRIMUS, the Nottingham Health Profile (NHP), the Unidimensional Fatigue Impact Scale (U-FIS), and demographic questions. RESULTS Cognitive debriefing interviews demonstrated the acceptability of the new language versions. Analysis of survey data showed that the new language versions of the three PRIMUS scales were unidimensional (as indicated by fit to the Rasch model) and that they had good internal consistency and reproducibility. PRIMUS scale scores correlated as expected with those on the NHP and the U-FIS. The scales in all countries were able to discriminate between groups of patients on the basis of their self-reported MS severity, general health, and employment status. CONCLUSIONS The PRIMUS was successfully adapted into eight new languages. Most of the tests showed the PRIMUS to have good unidimensionality and to have good internal consistency, reproducibility, and construct validity. The measure is now available for use in clinical studies and trials involving these countries and the UK. Further work is required to assess the measures responsiveness.

The German adaptation of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR).

BackgroundIndividuals with precapillary pulmonary hypertension (PH) experience severely impaired quality of life. A disease-specific outcome measure for PH, the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) was developed and validated in the UK and subsequently adapted for use in additional countries. The aim of this study was to translate and assess the reliability and validity of the CAMPHOR for German-speaking populations.MethodsThree main adaptation stages involved; translation (employing bilingual and lay panels), cognitive debriefing interviews with patients and validation (assessment of the adaptation’s psychometric properties). The psychometric evaluation included 107 patients with precapillary PH (60 females; age mean (standard deviation) 60 (15) years) from 3 centres in Austria, Germany and Switzerland.ResultsNo major problems were found with the translation process with most items easily rendered into acceptable German. Participants in the cognitive debriefing interviews found the questionnaires relevant, comprehensive and easy to complete. Psychometric analyses showed that the adaptation was successful. The three CAMPHOR scales (symptoms, activity limitations and quality of life) had excellent test-retest reliability correlations (Symptoms = 0.91; Activity limitations = 0.91; QoL = 0.90) and internal consistency (Symptoms = 0.94; Activity limitations = 0.93; QoL = 0.94). Predicted correlations with the Nottingham Health Profile provided evidence of the construct validity of the CAMPHOR scales. The CAMPHOR adaptation also showed known group validity in its ability to distinguish between participants based on perceived general health, perceived disease severity, oxygen use and NYHA classification.ConclusionsThe CAMPHOR has been shown to be valid and reliable in the German population and is recommend for use in clinical practice.

Validation of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) for the Australian and New Zealand population

Background and objective:  Individuals with pulmonary arterial hypertension (PAH) experience severely impaired quality of life. A disease‐specific patient reported outcome measure for PAH (the Cambridge Pulmonary Hypertension Outcome Review—CAMPHOR) has recently been developed and validated in the UK, USA and Canada. It has demonstrated reliability and validity in PAH populations in these countries. The aim of this study was to assess the reliability and validity of the CAMPHOR in an Australian and New Zealand (NZ) PAH population.

Interpreting scores on multiple sclerosis-specific patient reported outcome measures (the PRIMUS and U-FIS)

BackgroundThe PRIMUS is a Multiple Sclerosis (MS)-specific suite of outcome measures including assessments of QoL (PRIMUS QoL, scored 0-22) and activity limitations (PRIMUS Activities, scored 0-30). The U-FIS is a measure of fatigue impact (scored 0-66). These measures have been fully validated previously using an MS sample with mixed diagnoses. The aim of the present study was to validate the measures further in a specifically Relapse Remitting MS (RRMS) sample and to provide preliminary evidence of the responder definitions (RD; also known as minimal important difference) for these instruments.MethodsData were derived from a multi-country efficacy trial of MS patients with assessments at baseline and 12 months. Baseline data were used to assess the internal reliability and validity of the measures. Both anchor-based and distribution-based approaches were employed for estimating RD. Anchor-based estimates were based on published RD values for the EQ-5D and were assessed for those improving and deteriorating separately. Distribution-based estimates were based on standard error of measurement (SEM), change score equivalent to 0.30, and change score equivalent to 0.50, effect sizes (ES).ResultsThe sample included 911 RRMS patients (67.3% female, age mean (SD) 36.2 (8.4) years, duration of MS mean (SD) 4.8 (5.2) years). Results showed that the PRIMUS and U-FIS had good internal consistency. Appropriate correlations were observed with comparator instruments and both measures were able to distinguish between participants based on Expanded Disability Status Scale scores and time since diagnosis. The anchor-based and distribution-based RD estimates were: PRIMUS Activities range = 1.2-2.3, PRIMUS QoL range = 1.0-2.2, and U-FIS range = 2.4-7.0.ConclusionsThe results show that the PRIMUS and U-FIS are valid instruments for use with RRMS patients. The analyses provide preliminary information on how to interpret scores on the scales. These data will be useful for assessing treatment efficacy and for powering clinical studies.Trial Reference NumberClinicalTrials.gov Identifier NCT00340834.

Adaptation of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) into French-Canadian and English-Canadian.

BACKGROUND The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is the first disease-specific instrument for assessing patient-reported symptoms, functioning and quality of life (QoL) in pulmonary arterial hypertension (PAH). OBJECTIVES To create and validate French-Canadian (FC) and English-Canadian (EC) language versions of the CAMPHOR. METHODS A translation panel (for the FC version) and lay panels (for both versions) were convened to adapt the questionnaires (dual-panel methodology). Subsequently, these new questionnaires were field-tested in 15 FC PAH and 15 EC PAH patients. Finally, in a postal validation study, the new language versions of the CAMPHOR underwent psychometric evaluation in 41 FC and 52 EC PAH patients to test for reliability and validity. RESULTS The FC and EC field-test interview participants found the questionnaires relevant, comprehensible and easy to complete. Psychometric analyses showed that the FC and EC adaptations were successful. High test-retest coefficients for the scales after controlling for change in respondents QoL (FC: 0.92 to 0.96; EC: 0.85 to 0.99) indicated a high degree of reliability. The FC and EC CAMPHOR scales had good internal consistency (Cronbachs alpha coefficients 0.90 to 0.92 and 0.88 to 0.92, respectively). Predicted correlations with the Nottingham Health Profile provided evidence of the construct validity of the FC and EC scales. The FC and EC adaptations also showed known groups validity. CONCLUSIONS The FC and EC adaptations of the CAMPHOR have been shown to be reliable and valid for measures of health-related QoL and QoL in PAH, and thus can be recommended for use in clinical studies and routine practice in PAH.

International Development of the Unidimensional Fatigue Impact Scale (U-FIS)

OBJECTIVE The 22-item Unidimensional Fatigue Impact Scale (U-FIS) provides an index of the impact of fatigue on patients with multiple sclerosis (MS). The objective is to produce eight new language versions of the U-FIS: Canadian-English, Canadian-French, French, German, Italian, Spanish, Swedish, and US-English. METHODS The U-FIS was translated via two translation panels. Cognitive debriefing interviews conducted with patients in each country assessed face and content validity. Scaling and psychometric properties were assessed via survey data with patients in each country completing the U-FIS, Nottingham Health Profile (NHP), and demographic questions. RESULTS Cognitive debriefing interviews demonstrated U-FIS acceptability. Analysis of postal survey data showed all new language versions to be unidimensional. Reliability was high, with test-retest correlations and internal-consistency coefficients exceeding 0.85. Initial evidence of validity was provided by moderate to high correlations with NHP scales. The U-FIS was able to discriminate between groups based on employment status, perceived MS severity, and general health. CONCLUSION The U-FIS is a practical new measure of the impact of fatigue. It was successfully adapted into eight new languages to broaden availability for researchers. Psychometric analyses indicated that the new language versions were unidimensional and reproducible with promising construct validity.

Psychometric performance of the CAMPHOR and SF-36 in pulmonary hypertension

BackgroundThe Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) and the Medical Outcomes Study Short Form 36 (SF-36) are widely used to assess patient-reported outcome in individuals with pulmonary hypertension (PH). The aim of the study was to compare the psychometric properties of the two measures.MethodsParticipants were recruited from specialist PH centres in Australia and New Zealand. Participants completed the CAMPHOR and SF-36 at two time points two weeks apart. The SF-36 is a generic health status questionnaire consisting of 36 items split into 8 sections. The CAMPHOR is a PH-specific measure consisting of 3 scales; symptoms, activity limitations and needs-based QoL. The questionnaires were assessed for distributional properties (floor and ceiling effects), internal consistency (Cronbachs alpha), test-retest reliability and construct validity (scores by World Health Organisation functional classification).ResultsThe sample comprised 65 participants (mean (SD) age = 57.2 (14.5) years; n(%) male = 14 (21.5%)). Most of the patients were in WHO class 2 (27.7%) and 3 (61.5%). High ceiling effects were observed for the SF-36 bodily pain, social functioning and role emotional domains. Test-retest reliability was poor for six of the eight SF-36 domains, indicating high levels of random measurement error. Three of the SF-36 domains did not distinguish between WHO classes. In contrast, all CAMPHOR scales exhibited good distributional properties, test retest reliability and distinguished between WHO functional classes.ConclusionsThe CAMPHOR exhibited superior psychometric properties, compared with the SF-36, in the assessment of PH patient-reported outcome.

Adaptation and validation of the Cambridge pulmonary hypertension outcome review for Sweden

Background: The Cambridge pulmonary hypertension outcome review (CAMPHOR) is the first pulmonary hypertension-specific instrument for the assessment of the patient’s perceived symptoms, activity limitations and quality of life (QoL). Purpose: To produce and validate a Swedish language version of the CAMPHOR. Methods: Bilingual (n = 5) and lay panels (n = 5) were conducted to translate the CAMPHOR into Swedish. This new questionnaire was then field-tested with 14 patients and finally, it underwent psychometric evaluation by means of a postal validation study involving 38 patients with pulmonary hypertension (PH). Results: Few problems were experienced in translating the CAMPHOR into Swedish. The field-test participants found the scales relevant, comprehensible and easy to complete. Psychometric analyses showed that the Swedish adaptation was successful. The Swedish CAMPHOR scales had good internal consistency. Cronbach’s alpha coefficients were 0.92 for the symptoms scale, 0.92 for activity limitations and 0.95 for the quality of life. Predicted correlations with the Nottingham Health Profile provided evidence of the construct validity of the scales. The Swedish scales also indicated known groups validity. Conclusions: The Swedish version of the CAMPHOR is a reliable and valid measure of the impact of pulmonary hypertension on the lives of affected patients. It is recommended for use in clinical studies and routine practice in pulmonary hypertension patients.