The development and validation of the Unidimensional Fatigue Impact Scale (U-FIS).

BACKGROUND: The multidimensional assessment of fatigue is complicated by the interrelation of its multiple causes and effects. OBJECTIVE: The purpose of the research was to develop a unidimensional assessment of fatigue (U-FIS). METHODS: Data collected with the Fatigue Impact Scale (FIS) were subjected to Rasch analysis to identify potential problems with the scale. Additional items for the U-FIS were generated from interviews with UK MS patients. The U-FIS was tested for face and content validity in patient interviews and included in a validation survey to determine dimensionality (Rasch model), reliability and validity. RESULTS: The original FIS was not unidimensional when subscale items were combined. The modification of the FIS and addition of a number of items allowed the development of a 22-item unidimensional scale (U-FIS) that was reliable (Cronbach Alpha = 0.96; test-retest = 0.86,) and valid given correlations with the Nottingham Health Profile and ability to distinguish between MS severity groups. There was no significant difference in U-FIS scores according to MS type. CONCLUSION: It is valid to conceptualize the functional impact of fatigue as unidimensional. The U-FIS is a reliable and valid questionnaire that will allow the measurement of this construct in clinical studies.

The development of patient-reported outcome indices for multiple sclerosis (PRIMUS).

BACKGROUND: Complex diseases such as multiple sclerosis (MS) present dilemmas over the choice of patient-reported outcome measures as no single scale can inform on all types of MS impact from the patient's perspective. OBJECTIVE: To develop an outcome tool, the Patient-Reported Indices for Multiple Sclerosis (PRIMUS), to assess MS symptoms, activities, and quality of life. METHODS: PRIMUS content was derived from qualitative interviews with UK MS patients and checked by clinical experts. Semi-structured cognitive debriefing interviews assessed scale face and content validity. PRIMUS scaling properties, reliability, and construct validity were assessed by a test-retest postal survey. RESULTS: Cognitive debriefing interviews (n = 15) demonstrated scale clarity, relevance, and comprehensiveness. The postal survey was completed by 135 patients with MS. After removal of misfitting items and those exhibiting differential item functioning, all scales fitted the Rasch model, confirming unidimensionality. For all scales, test-retest reliability exceeded 0.80. Scale scores were related to perceived MS severity, general health, and symptoms of depression. Moderate correlations were observed between PRIMUS and Nottingham Health Profile scores. CONCLUSIONS: Clinicians and researchers can have confidence in scores obtained by respondents on the PRIMUS. The PRIMUS will aid the assessment of the impact of MS from the patient's perspective.

The development of the L-QoL: a quality-of-life instrument specific to systemic lupus erythematosus.

OBJECTIVES: Complex diseases, such as systemic lupus erythematosus (SLE), present dilemmas over choice of outcome measures. Using a battery of instruments to capture the impact of different impairments or activity limitations experienced does not provide assessment of the wider impact on quality of life (QoL). This paper describes the development and testing of a new instrument to measure QoL in systemic lupus erythematosus (L-QoL). METHODS: The development combines theoretical strengths of the needs-based QoL model with statistical and diagnostic powers of the Rasch model. Content was derived from in-depth interviews with relevant patients. Cognitive debriefing interviews assessed face and content validity. Rasch analysis was applied to data from an initial postal survey to remove misfitting items. A second postal survey assessed scaling properties, reliability, internal consistency and validity. RESULTS: A 55-item questionnaire was derived from interview transcripts. Cognitive debriefing confirmed acceptability. Rasch analysis of postal survey data (n = 95) removed misfitting items. A second postal survey (n = 93), produced a 25-item version with good item fit and stability, excellent test-retest reliability (0.92), internal consistency (0.92) and strict unidimensionality. CONCLUSIONS: It is concluded that the L-QoL should prove a valuable instrument for assessing patient-based outcome in clinical trials and practice.

The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR): a measure of health-related quality of life and quality of life for patients with pulmonary hypertension.

OBJECTIVE: No outcome measures specific to pulmonary hypertension (PH) currently exist. The aim of the study was to develop health-related quality of life (symptoms and functioning) scales and a quality of life scale that would allow comprehensive, accurate and valid patient-reported outcome assessment in clinical studies. METHODS: The content of the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) was derived from qualitative interviews conducted with 35 patients. Item reduction was based on the analysis of responses to a postal survey (n=75) and patient interviews (n=15) designed to determine face and content validity. A final postal validation study (n=91) was performed to determine reproducibility and construct validity. RESULTS: The questionnaire was well received by participants who found it to be relevant, comprehensible and quick and easy to complete. Rasch and factor analyses were conducted to ensure unidimensionality of the final CAMPHOR scales; Overall symptoms (made up of Energy, Breathlessness and Mood subscales), Functioning and Quality of life. The CAMPHOR scales had good internal consistency (alpha=0.90-0.92) and reproducibility (test-retest correlations=0.86-0.92). They also exhibited convergent, divergent and known groups validity. CONCLUSIONS: The CAMPHOR is a valuable new instrument for assessing patient-reported outcome in PH clinical trials and routine practice.

The development of a preference-based measure of health in children with atopic dermatitis.

BACKGROUND: Outcomes of health care interventions can be measured in many different ways, but there has been growing interest in the role that quality-adjusted life-years (QALYs) can play in informing priorities in health care. While existing generic preference-based measures can be used to obtain QALYs, these measures may often be inappropriate for some conditions such as atopic dermatitis (AD). These measures are also usually developed for adults and may not capture the domains pertinent to children. OBJECTIVES: To develop a preference-based quality-of-life measure for use in children with AD. METHODS: Items generated from interviews conducted with parents of children with AD were used to form a health state classification system that gives 16 unique health states. One hundred and fifty members of the general population were interviewed to derive preference weights for these states, following the methods used in the valuation of the Health Utilities Index 2 (HUI 2). Each person valued 10 health states using the standard gamble technique. The primary analysis was the estimation of mean health state values for each of the 16 states. RESULTS: Mean values across the 16 health states range from 0.36 (SD = 0.36) for the worst state to 0.84 (SD = 0.19) on a scale from zero to one, where zero is for health states thought to be as bad as being dead and one is for perfect health. There was some support for the validity of the values from the fact that the values were logically consistent with the ordering of the health state classification system. CONCLUSIONS: These results show the perceived importance of the defined health states of childhood AD to the general population. The resultant health state classification and values can be used to calculate QALYs for use in assessing the cost-effectiveness of interventions for children with AD.

Development of the PsAQoL: a quality of life instrument specific to psoriatic arthritis.

BACKGROUND: Patient reported outcome measures used in studies of psoriatic arthritis (PsA) have been found to be inadequate for determining the impact of the disease from the patient's perspective. OBJECTIVE: To produce the PsAQoL, a PsA-specific quality of life (QoL) instrument, employing the needs based model of QoL that would be relevant and acceptable to respondents, valid, and reliable. METHODS: Content was derived from qualitative interviews conducted with patients with PsA. Face and content validity were assessed by field test interviews with a new sample of patients with PsA. A postal survey was conducted to improve the scaling properties of the new measure. Finally, a test-retest postal survey was used to identify the final measure and to test its scaling properties, reliability, internal consistency, and validity. RESULTS: Analysis of the qualitative interview transcripts identified a 51 item questionnaire. Field test interviews confirmed the acceptability and relevance of the measure. Analysis of data from the first postal survey (n = 94) reduced the questionnaire to 35 items. Rasch analysis of data from the test-retest survey (n = 286) identified a 20 item version of the PsAQoL with good item fit. This version had excellent internal consistency (alpha = 0.91), test-retest reliability (0.89), and validity. CONCLUSIONS: The PsAQoL is a valuable tool for assessing the impact of interventions for PsA in clinical studies and trials. It is well accepted by patients, taking about three minutes to complete, is easy to administer, and has excellent scaling and psychometric properties.

Development of the PSORIQoL, a psoriasis-specific measure of quality of life designed for use in clinical practice and trials.

BACKGROUND: Patients with psoriasis have significant impairment in their quality of life (QoL). Several patient-completed instruments are available to measure outcome in dermatological conditions but these primarily focus on severity of disease rather than on QoL. OBJECTIVES: To develop a new instrument specifically designed to measure QoL in psoriasis-the Psoriasis Index of Quality of Life (PSORIQoL). METHODS: The content of the instrument was derived from qualitative interviews with 62 psoriasis patients in the U.K., Italy and the Netherlands. Content analysis of the interview transcripts from the three countries identified potential items for the questionnaire. All further stages of the project were conducted in the U.K. only. Face and content validity were determined by means of a focus group held with seven psoriasis patients and face-to-face interviews with a further 21 patients. A new draft version of the PSORIQoL, together with the Dermatology Life Quality Index (DLQI) and the General Well-Being Index (GWBI), were completed by a new sample of psoriasis patients contacted by mail, in order to determine construct validity. A subsample of the respondents completed a similar package 2 weeks later, to assess reproducibility (reliability). RESULTS: The first version of the PSORIQoL consisted of 61 items covering the needs identified in the interviews as having been affected by psoriasis or its treatment. These included fear of negative reactions from others, self-consciousness and poor self-confidence, problems with socialization, physical contact and intimacy, limitations on personal freedom and impaired relaxation, sleep and emotional stability. Following the focus group and field-test interviews, a new draft measure consisting of 45 items was completed by 148 patients, 88 of whom completed and returned a similar package 2 weeks later. Application of Rasch analysis identified a final 25-item version of the PSORIQoL. This version had a test-retest reliability coefficient of 0.89, indicating good reproducibility. The levels of association with the DLQI and PGWB indicated that the PSORIQoL measures a related but distinct construct. CONCLUSIONS: The PSORIQoL appears to be a practical, reliable and valid instrument for measuring the impact of psoriasis on QoL. It remains necessary to establish the instrument's responsiveness to changes in QoL associated with treatment.

Development of the ASQoL: a quality of life instrument specific to ankylosing spondylitis.

BACKGROUND: Although disease-specific health status measures are available for ankylosing spondylitis (AS), no instrument exists for assessing quality of life (QoL) in the condition. OBJECTIVE: To produce an AS-specific QoL measure that would be relevant and acceptable to respondents, valid, and reliable. METHODS: The ASQoL employs the needs-based model of QoL and was developed in parallel in the UK and the Netherlands (NL). Content was derived from interviews with patients in each country. Face and content validity were assessed through patient field test interviews (UK and NL). A postal survey in the UK produced a more efficient version of the ASQoL, which was tested for scaling properties, reliability, internal consistency, and validity in a further postal survey in each country. RESULTS: A 41 item questionnaire was derived from interview transcripts. Field testing interviews confirmed acceptability. Rasch analysis of data from the first survey (n=121) produced a 26 item questionnaire. Rasch analysis of data from the second survey (UK: n=164; NL: n=154) showed some item misfit, but showed that items formed a hierarchical order and were stable over time. Problematic items were removed giving an 18 item scale. Both language versions had excellent internal consistency (alpha=0.89-0.91), test-retest reliability (r(s)=0.92 UK and r(s)=0.91 NL), and validity. CONCLUSIONS: The ASQoL provides a valuable tool for assessing the impact of interventions for AS and for evaluating models of service delivery. It is well accepted by patients, taking about four minutes to complete, and has excellent scaling and psychometric properties.

International development of the Quality of Life in Depression Scale (QLDS).

BACKGROUND: The Quality of Life in Depression Scale (QLDS) employs the needs-based model of quality of life (QoL) and was developed in the UK and The Netherlands as an outcome measure for clinical trials. This paper describes the production and psychometric assessment of nine new language versions for Canada (French and English), Denmark, France, Germany, Italy, Morocco, Spain and the US. METHODS: Three adaptation stages were employed; production of conceptually equivalent translations, field-test interviews and assessment of reliability and construct validity by survey of patients with major depression. RESULTS: Few problems were experienced with producing conceptually equivalent translations, except in Morocco. Patients in the field-test interviews found the instrument to have appropriate content and to be easy to complete. Internal consistency and test-retest reliability were excellent for all language versions and scores were found to relate appropriately to measures of depression severity and health status. LIMITATIONS: Further investigation is required of the ability of the measure to assess individuals at the extremes of the QoL continuum. Data collected with the Arabic QLDS should not be combined with those from other countries. CONCLUSIONS: The QLDS is the first instrument designed to assess QoL in depression based on a coherent model of the construct. Each language version has been shown to be well accepted by respondents and to have excellent psychometric properties. As the instrument is now available in a large number of languages, the QLDS is the QoL instrument of choice for inclusion in clinical trials of interventions for depression.

The development of a quality of life instrument for use with post-menopausal women with urogenital atrophy in the UK and Sweden.

Many post-menopausal women suffer from oestrogen deficiency. This can cause urogenital atrophy which leads to symptoms such as dyspareunia, dysuria, vaginal dryness and urge incontinence. Even though urogenital atrophy is a common condition, little attempt has been made to investigate the impact that the condition has on the quality of life of the women concerned. A quality of life instrument specifically for use with women with urogenital atrophy was developed. The needs-based approach to quality of life was adopted, which states that quality of life is the extent to which an individual is able to satisfy her needs. The development work was undertaken simultaneously in the UK and Sweden. The measure was found to be acceptable and relevant to women in both countries and to have good levels of test-retest reliability (0.92 in the UK and 0.85 in Sweden), internal consistency (alpha coefficients 0.90 in both countries) and construct validity. It is suitable for use in clinical trials and for monitoring the progress of patients in clinical practice.

The QoL-AGHDA: an instrument for the assessment of quality of life in adults with growth hormone deficiency.

Several studies have shown that growth hormone deficiency in adults leads to poor well-being and other clinical consequences, and that these improve when the hormone is replaced. However, the studies employed generic measures of health status that miss important aspects of the patients' experience and that have inadequate reliability and responsiveness. This paper describes the European development and testing of the Quality of Life-Assessment of Growth Hormone Deficiency in Adults (QoL-AGHDA), a condition-specific quality of life measure for use in clinical trials and for the routine monitoring of patients. The instrument was produced in five languages; English, Swedish, Italian, German and Spanish. Each language version is shown to have good reliability, internal consistency and construct validity. The QoL-AGHDA is currently included in an international database monitoring the long-term efficacy and safety of growth hormone replacement therapy and in clinical trials in a number of countries.

The international development of the RGHQoL: a quality of life measure for recurrent genital herpes.

This paper describes the international development and psychometric testing of the Recurrent Genital Herpes Quality of Life Questionnaire (RGHQoL), a condition-specific quality of life (QoL) instrument. The theoretical foundation for the measure is the needs-based model of QoL and the content of the instrument was derived from in-depth qualitative interviews with relevant patients in the UK. Versions of the RGHQoL were required for the UK, USA, Italy, Germany, France and Denmark for use in international clinical trials. The results indicate that the final 20 item measure has good reliability, internal consistency and validity for all language versions. A small responsiveness study in Denmark suggested that the measure is sensitive to changes in QoL associated with the initiation of suppression treatment for recurrent genital herpes (RGH). It is concluded that the RGHQoL is a valuable instrument for inclusion in clinical trials. The psychometric properties of the instrument are such that it may also be used to monitor the progress of individual patients.

The development and testing of the well-being index for surgical patients (WISP).

The development and testing of the Well-being Index for Surgical Patients (WISP), an instrument designed to assess the well-being of patients between 1 and 4 months after abdominal surgery, is described. The measure was intended for use in a study of the effectiveness of a dietary supplement for patients undergoing such surgery. Interviews were conducted with 15 patients who had had abdominal operations between 1 and 4 months previously. They provided information about their well-being at the time of their interview and also during the period since they had been discharged from hospital. A draft questionnaire was derived from the interviews and field tested with a further 17 patients who found the content to be relevant and the questionnaire easy to complete. A further 44 patients completed the measure on three occasions; 1, 2 and 4 months after abdominal surgery. The instrument was shown to have good internal consistency and produced statistically significant improvements in well-being over time. A postal survey with 20 patients indicated that the instrument's test-retest reliability was adequate. The WISP is acceptable to patients and easy to administer, making it suitable for inclusion in clinical trials.

The Development and Psychometric Properties of the MSQOL: A Migraine-Specific Quality-of-Life Instrument.

This paper describes the development and testing of the UK version of the Migraine-Specific Quality-of-Life instrument (MSQOL), a measure designed to assess the quality of life of migraineurs. The work was part of an international research study conducted in eight countries, with the initial development work conducted in the UK and the USA. In the UK, interviews were held with 30 patients with migraine, while in the USA, 25 individual interviews were conducted, along with one focus group with 5 participants. Transcripts were produced of the interviews/group discussion and these were used to determine the questionnaire items, which were then considered by an international translation panel. The panel considered the feasibility of translating the items into other European languages. The instrument was then assessed for reliability and validity. The UK version of the MSQOL was shown to have excellent test-retest reliability (0.93 over 2 weeks) and internal consistency (0.92 and 0.93 on the first and second administrations, respectively). Scores on the measure were also found to be related to a comparator measure of well-being and to perceived severity of migraine and disruption caused to patients by the disease. Findings for the other language versions of the MSQOL supported those from the UK, suggesting that the instrument may well be suitable for inclusion in clinical trials.

Quality-of-life assessment of adults with growth hormone deficiency. Implications for drug therapy.

Growth hormone (GH) deficiency in adults affects many physiological functions. It may result in reduced muscle volume and strength, changes in body mass, lowered metabolic rate, low energy and sexual drive and impaired cognitive function. GH deficiency may also lead to an increase in mortality due to vascular disorders. However, the benefits of GH replacement are still controversial. Recently, investigators have looked at the effects of GH replacement therapy on the well-being of patients. However, the studies which have been published generally have small sample sizes, use inadequate methodology and employ health status measures that lack the necessary sensitivity. Despite these weaknesses, results suggest that replacement GH does have a positive effect on well-being. A GH-specific quality-of-life measure has now been produced, which will provide a clearer view of the benefits of replacement therapy for patients. The use of this measure should help guide decisions about the necessity of providing replacement therapy for GH-deficient patients.

Preliminary report on the development of a disease-specific instrument for assessing quality of life of adults with growth hormone deficiency.

It is notable that many of the feelings described by the people in the sample are similar to those experienced at times by people who do not suffer from GHD, that is, lapses of memory, feeling drained of energy, loss of temper, loss of motivation, difficulty in concentrating, forgetfulness and having a tendency to gain weight. Adults with GHD, however, appear to suffer these problems more frequently and to a more extreme degree than other people. It is clear that the range of problems that afflict people with GHD is great, and that the repercussions affect virtually all aspects of their lives. The results from these interviews will form the basis of a measure designed specifically to assess the quality of life of patients with GHD, and to determine the changes in quality of life after treatment with GH.