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 (α=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.
The CAMPHOR is a valuable new instrument for assessing patient-reported outcome in PH clinical trials and routine practice.
Due to the international nature of many clinical studies and trials it is often necessary to produce several language versions of specific measures. While it is generally acknowledged that it is necessary to produce versions that are conceptually equivalent, the best method of achieving this is more controversial. It is commonly stated that there is a gold-standard method, which involves forward and backward translation. However, no evidence has been presented to support this view. This paper argues that the "gold-standard" method is difficult to support and describes an alternative method involving dual translation panels that has been used in the production of all adaptations of needs-based quality of life instruments.
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 (a = 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.
This paper considers and defines the different types of patient-reported outcomes that can be collected in clinical studies. In particular, it argues that quality of life (QoL) is a distinctly different type of outcome from Health-Related Quality of Life (HRQL). QoL is seen as providing an overall assessment of the effect of both illness and its treatment on the patient. In contrast, HRQL assesses issues that are of clinical or societal importance that may or may not cause concern to the patient. Needs-based QoL is defined and it is argued that this approach (the extent to which an individual is able to meet his or her needs) provides a good working indicator of QoL.
The use of patient reported outcome scales in clinical trials conducted by the pharmaceutical industry has become more widespread in recent years. The use of such outcomes is particularly common for products developed to treat chronic, disabling conditions where the intention is not to cure but to ameliorate symptoms, facilitate functioning or, ultimately, to improve quality of life. In such cases, patient reported evidence is increasingly viewed as an essential complement to traditional clinical evidence for establishing a product's competitive advantage in the marketplace. In a commercial setting, the value of patient reported outcomes is viewed largely in terms of their potential for securing a labelling claim in the USA or inclusion in the summary of product characteristics in Europe. Although, the publication of the recent US Food and Drug Administration guidance makes it difficult for companies to make claims in the USA beyond symptom improvements, the value of these outcomes goes beyond satisfying requirements for a label claim. The European regulatory authorities, payers both in the US and Europe, clinicians and patients all play a part in determining both the availability and the pricing of medicinal products and all have an interest in patient-reported data that go beyond just symptoms. The purpose of the current paper is to highlight the potential added value of patient reported outcome data currently collected and held by the industry for these groups.
Cost-utility models are increasingly used in many countries to establish whether the cost of a new intervention can be justified in terms of health benefits. Health-state utility (HSU) estimates (the preference for a given state of health on a cardinal scale where 0 represents dead and 1 represents full health) are typically among the most important and uncertain data inputs in cost-utility models. Clinical trials represent an important opportunity for the collection of health-utility data. However, trials designed primarily to evaluate efficacy and safety often present challenges to the optimal collection of HSU estimates for economic models. Careful planning is needed to determine which of the HSU estimates may be measured in planned trials; to establish the optimal methodology; and to plan any additional studies needed. This report aimed to provide a framework for researchers to plan the collection of health-utility data in clinical studies to provide high-quality HSU estimates for economic modeling. Recommendations are made for early planning of health-utility data collection within a research and development program; design of health-utility data collection during protocol development for a planned clinical trial; design of prospective and cross-sectional observational studies and alternative study types; and statistical analyses and reporting.
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.
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