Temporal Artery Biopsy vs ULtrasound in Diagnosis of GCA (TABUL)
Palabras clave
Abstracto
Descripción
OVERALL DESIGN: The overall design consists of a cohort study of 402 participants with suspected GCA who will be followed up for 6 months; a cost-effectiveness study comparing ultrasound with temporal artery biopsy; a study of observer agreement in evaluating ultrasound and temporal artery biopsies; and an expert panel assessing the appropriateness of alternative strategies for diagnosing and treating patients with suspected GCA.
PRIMARY OBJECTIVES:
1. To evaluate the diagnostic accuracy (sensitivity and specificity) of ultrasound as an alternative to temporal artery biopsy for the diagnosis of GCA in patients referred for biopsy with suspected GCA.
2. To evaluate the cost-effectiveness (incremental cost per QALY) of ultrasound instead of biopsy in the diagnosis of GCA.
SECONDARY OBJECTIVES:
3. To evaluate inter-observer agreement in the assessment of ultrasound and temporal artery biopsy.
4. To elicit expert views on the appropriateness of performing a biopsy following ultrasound using clinical vignettes.
5. To evaluate the diagnostic accuracy (sensitivity and specificity) of the sequential diagnostic strategy from 4 as an alternative to temporal artery biopsy alone in the diagnosis of GCA.
6. To evaluate the cost-effectiveness (incremental cost per QALY) of the diagnostic strategy from 4 instead of biopsy alone in the diagnosis of GCA.
DESIGN:
A prospective cohort study to evaluate the impact of ultrasound or biopsy of temporal arteries on diagnosis of GCA and treatment decisions . The cohort study will use a paired design, i.e. all participants will have both US and biopsy, with diagnostic performance assessed against a composite reference standard diagnosis following final (6 months) assessment. To evaluate the impact of US/biopsy results on clinical practice and longer term outcomes, we will derive clinical vignettes based on cases recruited to the study, and present them to the treating clinician, along with either the ultrasound, or biopsy or both results, so that they can indicate diagnosis and proposed treatment. The main cost-effectiveness analyses will evaluate incremental cost per quality adjusted life year (QALY) on a long term (lifetime) horizon between diagnostic strategies.
SETTING:
Outpatient and inpatient rheumatology and ophthalmology departments in 25 National Health Service (NHS) trusts in the United Kingdom (UK) (also sites in Europe of required) with access to high resolution US.
TARGET POPULATION: Patients with suspected GCA who would normally require an urgent temporal artery biopsy, i.e. referrals from primary care and suspected GCA identified in secondary care. Recruitment of participants will be restricted to patients for whom US and biopsy can be performed within 7 days of starting high-dose steroids.
HEALTH TECHNOLOGIES BEING ASSESSED:
Halo, stenosis, or occlusion assessed by high resolution US; presence of giant cells or granulomatous inflammation on temporal artery biopsy.
MEASUREMENT OF COST AND OUTCOMES:
Data collection at baseline, 2 weeks and 6 months will include clinical and laboratory markers of disease activity, resource use, health-related quality of life (HRQoL) using the EuroQol-5D (EQ-5D), and adverse events. Baseline assessment will include retrospective assessment of symptoms and erythrocyte sedimentation rate/C-reactive protein (ESR/CRP) results before starting steroids. The reference standard diagnosis will be made using a composite of American College of Rheumatology classification criteria, GCA-related events, and alternative diagnoses using data collected at all assessments. Proposed treatment data will be collected from participating clinicians after each test result is released, and classified as treatment for GCA (e.g. initiate/continue steroids) or not GCA (e.g. withdraw/rapid taper of steroids) to compare changes in proposed treatment and evaluate agreement with the reference diagnosis. Unit costs of resources used will be obtained from nationally published sources where available. Modelling will estimate the impact of diagnostic strategies on clinical outcomes (e.g. GCA complications and steroid related adverse events), their costs and impact on HRQoL beyond study follow-up and within study follow-up. Probabilities of events, their cost and impact will be obtained from study data, a systematic literature review, or in the absence of relevant data, by formal elicitation of expert opinion. Costs and benefits will be discounted at 3.5% (National Institute for Health and Care Excellence [NICE] guidance) and uncertainty (including modelling assumptions) subjected to probabilistic sensitivity analysis and scenario analysis.
SAMPLE SIZE:
A sample size of 402 patients provides 90% power at a 5% type I error rate to test the joint hypothesis that (i) US has greater sensitivity than biopsy (to detect an increase in sensitivity from 76% for biopsy (assuming a 0.24 false negative fraction based on 9-44% biopsy-negative GCA) to 87% sensitivity for US; and (ii) to detect specificity of US of no less than 0.83 based on an expected specificity of 0.96. This sample size will allow estimation of a one-sided rectangular confidence region for US false and true positive fractions, assuming 80% prevalence of GCA in patients having a biopsy for suspected GCA, with the sample size inflated (gamma=0.1) due to uncertainty in the proportion of cases/controls in a cohort design. We will actually recruit 430 cases to allow for possible drop-outs from the study. In addition we will recruit 270 individuals for training purposes, to allow each centre to learn the technique of temporal artery and axillary artery scanning. Each centre will collect 10 such individuals (training cases), who will be of similar age and gender as the study cohort, but who will not have temporal arteritis. This is very important in order to ensure that observers are trained to recognise the appearances seen in normal (non GCA arteries) especially patients with atherosclerosis. Further ultrasound training including a video exam (to identify images of both normal and abnormal features of GCA) and a 'hot' case assessment (scanning a patient with GCA) will be designed into the ultrasound training programme. In addition, we will provide adequate training days (e.g. 2 separate training days) when all observers will be trained formally by Dr Schmidt and other ultrasound experts to ensure adequate observer agreement. The first training day will be held prior to starting the recruitment of patients, and will be repeated after the first year.
PROJECT TIMETABLE:
Total: 48 months (UPDATED TO 60 MONTHS SEE BELOW) Month 1-6 Study materials/protocols prepared; Ethics and research governance approval complete; Centres trained, approved and ready to recruit.
Month 7-12 Recruitment monitoring report; Quality control report. Month 13-18 Recruitment monitoring report; Quality control report; Additional centres (if required) trained, approved and ready to recruit; Month 19-24 Recruitment monitoring report; Quality control report. Month 25-30 Recruitment monitoring report; Quality control report; Web-based US and biopsy assessment developed.
Month 31-36 Recruitment completed; Clinical vignettes (web-based) developed. Month 37-42 Follow-up completed; Inter-rater assessment of US and biopsy images analysis competed; Expert panel review of vignettes completed.
Month 43-48 Database cleaned and locked; Analysis completed; statistical analysis and economic modelling, report drafting and preparation of papers. Final report completed.
PLEASE NOTE: 12 MONTH EXTENSION WAS GRANTED BY THE FUNDER (NIHR HTA) IN SEPTEMBER 2012 TO EXTEND THE RECRUITMENT PERIOD FROM THE END OF DECEMBER 2012 TO END OF DECEMBER 2013 (A FURTHER 12 MONTHS).
TH END OF STUDY WILL NOW BE DECEMBER 2014
The study will be overseen by a Trial Steering Committee (TSC) and an independent Data Monitoring Committee (DMC)at least 1 meeting per year.
BIOBANK:
We will develop a biobank of tissue, serum, DNA and ultrasound video imaging of blood vessels in GCA. An important benefit of the primary protocol is that we can use the accumulated material for a number of related projects.
fechas
| Verificado por última vez: | 06/30/2015 |
| Primero enviado: | 09/08/2009 |
| Inscripción estimada enviada: | 09/08/2009 |
| Publicado por primera vez: | 09/09/2009 |
| Última actualización enviada: | 07/15/2015 |
| Última actualización publicada: | 07/16/2015 |
| Fecha de inicio real del estudio: | 05/31/2010 |
| Fecha estimada de finalización primaria: | 11/30/2013 |
| Fecha estimada de finalización del estudio: | 11/30/2014 |
Condición o enfermedad
Intervención / tratamiento
Procedure: Ultrasound of temporal and axillary arteries
Procedure: Suspected GCA
Fase
Grupos de brazos
| Brazo | Intervención / tratamiento |
|---|---|
| Suspected GCA Patients who present with new onset of headache and suspected diagnosis of GCA. They will all require a temporal artery biopsy to assist in the diagnosis | Procedure: Suspected GCA Biopsy of temporal artery from symptomatic side |
| Training cohort Patients with any condition or healthy volunteers who are willing to consent ot have their temporal and axillary arteries examined using ultrasound, for training purposes |
Criterio de elegibilidad
| Edades elegibles para estudiar | 18 Years A 18 Years |
| Sexos elegibles para estudiar | All |
| Método de muestreo | Non-Probability Sample |
| Acepta voluntarios saludables | si |
| Criterios | Inclusion Criteria: for the cohort study 1. A clinical suspicion of new diagnosis of GCA e.g. patients with a new onset of headache, scalp tenderness, with or without elevated CRP or ESR, jaw or tongue claudication with or without visual loss. 2. The clinician decides that the patient requires an urgent temporal artery biopsy to determine whether or not the diagnosis is GCA. 3. The patient agrees and provides NHS consent to undergo a temporal artery biopsy as part of standard care. 4. Patients have been started on high dose glucocorticoids or will be started on high dose glucocorticoids. 5. Patients must be willing to attend for an ultrasound scan of their temporal and axillary arteries. 6. Participants must be willing to give informed written consent or willing to give permission for a nominated friend or relative to provide written informed assent if they are unable to do so because of physical disabilities e.g. sudden onset of blindness/vision loss which can be caused by GCA (this will be made clear in the ethics approval application). 7. Must be 18 years of age or over. For the training cases 1. Patients attending hospital outpatient or in patient departments for assessment for any condition (apart from giant cell arteritis or polymyalgia rheumatica) or healthy staff volunteers. 2. Above the age of 50 years. 3. Willing to attend for an ultrasound scan of their temporal and axillary arteries. 4. Willing and able to give written informed consent. Exclusion criteria: for the cohort study 1. Previous diagnosis of GCA. 2. Use of high dose glucocorticoid (>20mg prednisolone/day) for management of current suspected GCA for more than 7 days prior to the dates of the ultrasound and biopsy. 3. Long term (>1 month) high dose (>20mg per day at any time) steroids for conditions other than PMR, within three months prior to study entry. 4. Inability to give informed consent (either written consent or verbal assent from a relative or carer) 5. Inability to undergo an ultrasound scans of the temporal and axillary arteries. 6. Patients with a known cause of headache (not due to GCA), or any condition which would preclude the need for a temporal artery biopsy. 7. Patients who are unable to undergo an ultrasound scan and a temporal artery biopsy within 7 days of starting glucocorticoids. For the training cases 1. Diagnosis of suspected GCA or a previous history of diagnosed or suspected GCA. 2. Inability to give written informed consent. 3. Inability to undergo an ultrasound scans of the temporal and axillary arteries |
Salir
Medidas de resultado primarias
1. To evaluate the diagnostic accuracy of ultrasound vs temporal artery biopsy for diagnosis of suspected GCA and to evaluate the cost-effectiveness (incremental cost per QALY) of ultrasound instead of biopsy in the diagnosis of GCA. [Six months]
Medidas de resultado secundarias
1. To evaluate inter-observer agreement in the assessment of ultrasound and temporal artery biopsy [Six months]
2. To elicit expert views on the appropriateness of performing a biopsy following ultrasound using clinical vignettes [3 years]
3. To evaluate the diagnostic accuracy (sensitivity and specificity) of the sequential diagnostic strategy as an alternative to temporal artery biopsy alone in the diagnosis of GCA [3 years]
4. To evaluate the cost-effectiveness (incremental cost per QALY) of the diagnostic strategy of combined ultrasound and biopsy instead of biopsy alone in the diagnosis of GCA. [3 years]
5. Specific adverse events measured at each assessment; daily and cumulative steroid dose; steroid side effects; and pain or dysaesthesia at the biopsy site. [Six months]
6. Evolution of an alternative diagnosis [Six months]
7. Negative predictive value of ultrasound in preventing the need for temporal artery biopsies. [Six months]
8. Cost analysis of performing a screening ultrasound examination plus biopsy as part of the diagnostic workup of all patients with suspected GCA; or of performing a screening ultrasound examination instead of biopsy; or of performing a screening ultrasound [Six months]
9. Cost analysis of performing a screening ultrasound examination instead of biopsy in cases with a very low probability of GCA as part of the diagnostic workup of all patients with suspected GCA. [3 years]
10. Prediction of potential harm done to patients by over diagnosis or under diagnosis of GCA as a result of ultrasound use, either alone or in combination with biopsy [3 years]
11. Value of axillary artery ultrasound scanning in contributing to the diagnosis of GCA. [Six months]
12. Analysis of proportion of patients with a biopsy positive halo, stenosis, or occlusion assessed by high resolution ultrasound [3 years]
13. Presence of characteristic features of GCA on temporal artery biopsy in relation to clinical and ultrasound findings [2 weeks]
