Background Identification of the underlying cause of stroke and transient ischaemic attack (TIA) is important so that preventative therapy can be used to reduce the risk of recurrence. Transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) are diagnostic tools used to identify those cardiac sources of stroke that may respond to treatment. Objectives (1) Undertake systematic reviews to determine (a) the prevalence of cardiac sources of stroke and TIA and (b) the diagnostic accuracy of echocardiography; (2) undertake a survey to ascertain which guidelines and management strategies are used by UK stroke centres; and (3) evaluate the cost-effectiveness of the addition of TTE to the routine assessment of patients who have had a first-episode diagnosed stroke or TIA in the UK. Data sources Bibliographic databases including MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature, PsycINFO and the NHS Economic Evaluation Database were searched from inception to December 2010 (prevalence) or September 2011 (diagnostic accuracy). Bibliographies of related papers were screened and experts were contacted to identify additional published and unpublished references. Review methods The systematic reviews were undertaken according to the general principles recommended in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A decision-analytic model was developed to estimate the costs and quality-adjusted life-years accrued by each potential echocardiography strategy in the management of stroke and TIA for patients aged 45, 55 and 65 years. The model took a lifetime horizon and a NHS perspective. Costs and health benefits were discounted at an annual rate of 3.5%. Evidence to enable modelling was found for left atrial thrombus only. The cost-effectiveness of echocardiography is therefore based on all stroke patients being tested but only those with a left atrial thrombus receiving the benefits and harms of treatment. To describe current NHS stroke management practice we provided a questionnaire to the lead clinician of all stroke units in the UK. Results The searches identified 17,278 citations for the systematic review of the prevalence of potential cardiac sources of stroke and TIA, of which 65 studies were included. Patent foramen ovale was the most frequently reported pathology, followed by atrial septal aneurysm and mitral valve prolapse, with prevalence ranging from 0.25% to 73%, from 0.4% to 28% and from 0% to 31.6% respectively. For the systematic review of the diagnostic accuracy of echocardiography, 16,504 citations were identified, of which 51 studies were included. The pooled sensitivity to detect left atrial thrombus in three studies using transthoracic echocardiography in second harmonic imaging mode (TTEh) was 0.79 [95% credible interval (CrI) 0.47 to 0.94], with a pooled specificity of 1.00 (95% CrI 0.99 to 1.00) compared with TOE. Differences in the diagnostic accuracy of tests occurred mostly in their sensitivity to detect cardiac sources of stroke. No adverse events data were reported. Our principal economic finding is that TTEh is a cost-effective use of NHS resources compared with TOE when clinicians deem it the most appropriate test. The survey showed that the decision-making process for the management of stroke and TIA is very complex and varies considerably by site. It is clear that to accurately describe current management practice a very sophisticated questionnaire would be required. Limitations The prevalence review highlights the difficulties that clinicians face when identifying the cause of cardioembolic stroke (the limitations of the tests, the confounding comorbidities and the inherent mobility of blood clots). The diagnostic accuracy review was limited by the small number of studies reporting data or because studies included too few participants with a cardiac pathology, leaving a large degree of uncertainty about the underlying diagnostic accuracy. The economic model has limitations because of the limited data available for important parameters such as the efficacy of treatment in reducing stroke recurrence. Conclusion The economic analysis indicates that, in those cases in which TTEh is deemed the most appropriate test, it is a cost-effective use of NHS resources. However, this analysis has highlighted a lack of evidence in several areas and the results of the economic evaluation should therefore be treated with caution. There is a need for further evaluation of current echocardiography technologies, the causal associations between potential risk factors and stroke and whether or not anticoagulation therapies prevent recurrent stroke. Studies attempting to establish the prevalence of cardiac sources of stroke should identify all potential risk factors, rule out those that are not relevant and grade the findings according to risk. Research is also needed to reduce the uncertainty around the estimates of the sensitivity and specificity of TTEh and TOE, singly and in combination, in detecting treatable cardiac abnormalities compared with the 'gold standard' in each pathology. Study registration The study is registered as PROSPERO no. CRD42011001353. Funding The National Institute for Health Research Health Technology Assessment programme.
BACKGROUNDThe National Institute for Health and Care Excellence recommends the use of generic preference-based measures (GPBMs) of health for its Health Technology Assessments (HTAs). However, these data may not be available or appropriate for all health conditions.OBJECTIVESTo determine whether GPBMs are appropriate for some key conditions and to explore alternative methods of utility estimation when data from GPBMs are unavailable or inappropriate.DESIGNThe project was conducted in three stages: (1) A systematic review of the psychometric properties of three commonly used GPBMs [EQ-5D, SF-6D and Health Utilities Index Mark 3 (HUI3)] in four broadly defined conditions: visual impairment, hearing impairment, cancer and skin conditions. (2) Potential modelling approaches to 'map' EQ-5D values from condition-specific and clinical measures of health [European Organisation for Research and Treatment of Cancer Quality-of-life Questionnaire Core 30 (EORTC QLQ-C30) and Functional Assessment of Cancer Therapy - General Scale (FACT-G)] are compared for predictive ability and goodness of fit using two separate data sets. (3) Three potential extensions to the EQ-5D are developed as 'bolt-on' items relating to hearing, tiredness and vision. They are valued using the time trade-off method. A second valuation study is conducted to fully value the EQ-5D with and without the vision bolt-on item in an additional sample of 300 people.SETTINGThe valuation surveys were conducted using face-to-face interviews in the respondents' homes.PARTICIPANTSTwo representative samples of the UK general population from Yorkshire (n=600).INTERVENTIONSNone.MAIN OUTCOME MEASURESComparisons of EQ-5D, SF-6D and HUI3 in four conditions with various generic and condition-specific measures. Mapping functions were estimated between EORTC QLQ-C30 and FACT-G with EQ-5D. Three bolt-ons to the EQ-5D were developed: EQ + hearing/vision/tiredness. A full valuation study was conducted for the EQ + vision.RESULTS(1) EQ-5D was valid and responsive for skin conditions and most cancers; in vision, its performance varied according to aetiology; and performance was poor for hearing impairments. The HUI3 performed well for hearing and vision disorders. It also performed well in cancers although evidence was limited and there was no evidence in skin conditions. There were limited data for SF-6D in all four conditions and limited evidence on reliability of all instruments. (2) Mapping algorithms were estimated to predict EQ-5D values from alternative cancer-specific measures of health. Response mapping using all the domain scores was the best performing model for the EORTC QLQ-C30. In an exploratory analysis, a limited dependent variable mixture model performed better than an equivalent linear model. In the full analysis for the FACT-G, linear regression using ordinary least squares gave the best predictions followed by the tobit model. (3) The exploratory valuation study found that bolt-on items for vision, hearing and tiredness had a significant impact on values of the health states, but the direction and magnitude of differences depended on the severity of the health state. The vision bolt-on item had a statistically significant impact on EQ-5D health state values and a full valuation model was estimated.CONCLUSIONSEQ-5D performs well in studies of cancer and skin conditions. Mapping techniques provide a solution to predict EQ-5D values where EQ-5D has not been administered. For conditions where EQ-5D was found to be inappropriate, including some vision disorders and for hearing, bolt-ons provide a promising solution. More primary research into the psychometric properties of the generic preference-based measures is required, particularly in cancer and for the assessment of reliability. Further research is needed for the development and valuation of bolt-ons to EQ-5D.FUNDINGThis project was funded by the UK Medical Research Council (MRC) as part of the MRC-NIHR methodology research programme (reference G0901486) and will be published in full in Health Technology Assessment; Vol. 18, No. 9. See the NIHR Journals Library website for further project information.
Objective – The project sought to examine the aspects of the question answering process in an evidence based library and information practice (EBLIP) context by presenting the questions asked, articles selected, and checklists used by an opportunistic sample of Australian and New Zealand library and information professionals from multiple library and information sectors participating in the “Evidence Based Library and Information Practice: Delivering Services That Shine” (EBLIP-Gloss) FOLIOz e-learning course. Methods – The researchers analyzed the “ask,” “acquire,” and “appraise” tasks completed by twenty-nine library and information professionals working in Australia or New Zealand. Questions were categorized by EBLIP domain, articles were examined to identify any comparisons, and checklists were collated by frequency. Results – Questions fell within each of the six EBLIP domains, with management being the most common. Timeliness, relevance, and accessibility were stronger determinants of article selection than rigour or study design. Relevance, domain, and applicability were the key determinants in selecting a checklist. Conclusion – This small-scale study exemplifies the EBLIP process for a self-selecting group of library and information professionals working in Australia and New Zealand. It provides a snapshot of the types of questions that library and information practitioners ask, and the types of articles and checklists found to be useful. Participants demonstrated a preference for literature and checklists originating from within the library and information science (LIS) field, reinforcing the imperative for LIS professionals to contribute to EBLIP research.