Phase Specific Health Care Costs Associated with Giant Cell Arteritis in Ontario, Canada.

OBJECTIVE: To estimate the additional health care system costs associated with giant cell arteritis (GCA) in the year pre-diagnosis, post diagnosis, and over long-term follow up compared to individuals with similar demographics and comorbidities without GCA. METHODS: We performed a population-based study using health administrative data. Newly diagnosed cases of GCA (between 2002 and 2017 and ages 66 years and older) were identified using a validated algorithm and matched 1:6 to comparators using propensity scores. Follow up data was accrued until death, outmigration, or March 31, 2020. The costs associated with care were determined across three phases: the year before the diagnosis of GCA, the year after, and ongoing costs thereafter. RESULTS: The cohort consisted of 6,730 cases of GCA and 40,380 matched non-GCA comparators. The average age was 77 years (interquartile range 72-82) and 68.2% were female. A diagnosis of GCA was associated with an increased cost of $6,619.4 (95% CI 5,964.9 - 7274.0) per patient during the 1-year pre-diagnostic period; $12,150.3 (95% CI 11,233.1 - 13,067.6) per patient in the 1-year post-diagnostic phase, and $20,886.2 (95% CI 17,195.2 - 24,577.2) per patient during ongoing care for year 3 onwards. Increased costs were driven by inpatient hospitalizations, physician services, hospital outpatient clinic services, and emergency department visits. CONCLUSION: A diagnosis of GCA was associated with increased health care costs during all three phases of care. Given the substantial economic burden, strategies to reduce the healthcare utilization and costs associated with GCA are warranted.

Risk of Relapse of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in a Randomized Controlled Trial of Plasma Exchange and Glucocorticoids.

OBJECTIVE: Relapses of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis are important events that can cause organ dysfunction and reduce quality of life. Understanding the effects of the initial treatments for ANCA-associated vasculitis on the subsequent risk of relapse may help guide monitoring and treatment. METHODS: We performed a post hoc analysis of participants with severe ANCA-associated vasculitis enrolled in an international two-by-two factorial randomized controlled trial comparing the effects of plasma exchange (PLEX) to no PLEX and a regimen of reduced glucocorticoid exposure to a standard regimen. We estimated the effects of treatments on relapses of any severity using three competing risk time-to-event models adjusted for patient and disease characteristics and other treatments. Each model was adjusted for disease manifestations in different ways. RESULTS: Of 704 participants, 649 (92.2%) achieved remission and 147 (22.7%) experienced 204 relapses. The relapse rate was 10.3 (95% confidence interval [CI] 8.4-12.1) relapses per 100 patient-years. Neither the use of PLEX (subhazard ratio 0.91-0.94; 95% CIs range from 0.66 to 1.31) nor a glucocorticoid regimen (subhazard ratio 0.93-0.94; 95% CIs range from 0.67 to 1.35) appreciably changed the risk of relapse. Proteinase 3-ANCA and the presence of nonhemorrhagic respiratory manifestations of the disease at trial entry were associated with increased risks of relapse. Receiving dialysis at baseline and administration of oral cyclophosphamide as induction therapy were associated with lower risks of relapse. CONCLUSION: In patients with severe ANCA-associated vasculitis, relapses remain common; neither the use of PLEX nor an initial glucocorticoid tapering regimen impacted relapse risk.

Current and future advances in practice: a practical approach to the diagnosis and management of primary central nervous system vasculitis.

Primary CNS vasculitis (CNSV) is a rare, idiopathic autoimmune disease that, if untreated, can cause significant morbidity and mortality. It is a challenging diagnosis due to multiple mimics that can be difficult to differentiate, given that the CNS is an immunologically privileged and structurally isolated space. As such, diagnosis requires comprehensive multimodal investigations. Usually, a brain biopsy is required to confirm the diagnosis. Treatment of CNSV involves aggressive immunosuppression, but relapses and morbidity remain common. This expert review provides the reader with a deeper understanding of presentations of CNSV and the multiple parallel diagnostic pathways that are required to diagnose CNSV (and recognize its mimics), highlights the important knowledge gaps that exist in the disease and also highlights how we might be able to care for these patients better in the future.

Guidelines for the Management of Adult Acute and Acute-on-Chronic Liver Failure in the ICU: Neurology, Peri-Transplant Medicine, Infectious Disease, and Gastroenterology Considerations

To develop evidence-based recommendations for clinicians caring for adults with acute liver failure (ALF) or acute on chronic liver failure (ACLF) in the ICU. The guideline panel comprised 27 members with expertise in aspects of care of the critically ill patient with liver failure or methodology. We adhered to the Society of Critical Care Medicine standard operating procedures manual and conflict-of-interest policy. Teleconferences and electronic-based discussion among the panel, as well as within subgroups, served as an integral part of the guideline development. In part 2 of this guideline, the panel was divided into four subgroups: neurology, peri-transplant, infectious diseases, and gastrointestinal groups. We developed and selected Population, Intervention, Comparison, and Outcomes (PICO) questions according to importance to patients and practicing clinicians. For each PICO question, we conducted a systematic review and meta-analysis where applicable. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence to decision framework to facilitate recommendations formulation as strong or conditional. We followed strict criteria to formulate best practice statements. We report 28 recommendations (from 31 PICO questions) on the management ALF and ACLF in the ICU. Overall, five were strong recommendations, 21 were conditional recommendations, two were best-practice statements, and we were unable to issue a recommendation for five questions due to insufficient evidence. Multidisciplinary, international experts formulated evidence-based recommendations for the management ALF and ACLF patients in the ICU, acknowledging that most recommendations were based on low quality and indirect evidence.

Guidelines for the Management of Adult Acute and Acute-on-Chronic Liver Failure in the ICU: Neurology, Peri-Transplant Medicine, Infectious Disease, and Gastroenterology Considerations.

OBJECTIVES: To develop evidence-based recommendations for clinicians caring for adults with acute liver failure (ALF) or acute on chronic liver failure (ACLF) in the ICU. DESIGN: The guideline panel comprised 27 members with expertise in aspects of care of the critically ill patient with liver failure or methodology. We adhered to the Society of Critical Care Medicine standard operating procedures manual and conflict-of-interest policy. Teleconferences and electronic-based discussion among the panel, as well as within subgroups, served as an integral part of the guideline development. INTERVENTIONS: In part 2 of this guideline, the panel was divided into four subgroups: neurology, peri-transplant, infectious diseases, and gastrointestinal groups. We developed and selected Population, Intervention, Comparison, and Outcomes (PICO) questions according to importance to patients and practicing clinicians. For each PICO question, we conducted a systematic review and meta-analysis where applicable. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence to decision framework to facilitate recommendations formulation as strong or conditional. We followed strict criteria to formulate best practice statements. MEASUREMENTS AND MAIN RESULTS: We report 28 recommendations (from 31 PICO questions) on the management ALF and ACLF in the ICU. Overall, five were strong recommendations, 21 were conditional recommendations, two were best-practice statements, and we were unable to issue a recommendation for five questions due to insufficient evidence. CONCLUSIONS: Multidisciplinary, international experts formulated evidence-based recommendations for the management ALF and ACLF patients in the ICU, acknowledging that most recommendations were based on low quality and indirect evidence.

Effect of pregnancy on scleroderma progression.

Objective: To explore the trajectory of scleroderma disease activity in women who experienced a pregnancy after systemic sclerosis diagnosis compared to nulliparous women. Methods: We analyzed data from the Canadian Scleroderma Research Group registry by identifying nulliparous women and women with ⩾1 pregnancy after systemic sclerosis diagnosis. Patient characteristics were compared between groups at registry entry. Controlling for age, smoking, and time since systemic sclerosis diagnosis, generalized estimating equations tested the effect of pregnancy on force vital capacity, diffusing capacity of the lungs for carbon monoxide, right ventricular systolic pressure, glomerular filtration rate, antibody status, active digital ulcers, physician global assessment of activity, and severity over 9 years. Results: At registry entry, numbers of women in the nulliparous and pregnancy after systemic sclerosis diagnosis groups were 153 and 45, respectively. Corresponding numbers at 6 and 9 years were 48 and 21, and 18 and 9, respectively. The prevalence of anti-topoisomerase positivity was 18.3% in nulliparous and 12.5% in pregnancy after systemic sclerosis diagnosis. Baseline differences included mean (Standard deviation) age of diagnosis (nulliparous: 38.8 (14.0), pregnancy after systemic sclerosis diagnosis: 22.6 (6.8) years, p < 0.001), disease duration (nulliparous: 9.6 (8.9), pregnancy after systemic sclerosis diagnosis: 21.9 (9.6) years; p < 0.001), and inflammatory arthritis (nulliparous: 41 (28%), pregnancy after systemic sclerosis diagnosis: 22 (49%), p = 0.009). There were no significant differences between groups in the change of any outcomes over time. Conclusion: Results demonstrated that having ⩾1 pregnancy after systemic sclerosis diagnosis did not appear to significantly impact long-term renal, respiratory, or global function outcomes. While this offers a hopeful message to systemic sclerosis patients planning a pregnancy, physicians and patients should remain vigilant for potential post-partum complications.

Ocular manifestations of ANCA-associated vasculitis.

OBJECTIVES: ANCA-associated vasculitis (AAV) is a group of multisystem diseases that can have several ocular manifestations. There are published data on ocular manifestations of granulomatosis with polyangiitis (GPA), but few for eosinophilic granulomatosis with polyangiitis (EGPA) or microscopic polyangiitis (MPA). There is little information concerning chronicity, complications, and association with other cranial manifestations of AAV. METHODS: This study retrospectively analysed longitudinal multicentre cohorts of individuals with AAV followed between 2006 and 2022. Data included diagnosis, demographics, cranial manifestations of disease, presence of manifestations at onset of disease and/or follow-up, and ocular complications of disease. Univariate and multivariable logistic regression analysis assessed associations across disease manifestations. RESULTS: Data from 1441 patients were analysed, including 395 with EGPA, 876 with GPA, and 170 with MPA. Ocular manifestations were seen within 23.1% of patients: 39 (9.9%) with EGPA, 287 (32.7%) with GPA, and 12 (7.1%) with MPA at any time in the disease course. There were more ocular manifestations at onset (n = 224) than during follow-up (n = 120). The most common disease-related manifestations were conjunctivitis/episcleritis and scleritis. In multivariable analysis, dacryocystitis, lacrimal duct obstruction, and retro-orbital disease were associated with sinonasal manifestations of GPA; ocular manifestations were associated with hearing loss in MPA. The most common ocular complications and/or damage seen were cataracts (n = 168) and visual impairment (n = 195). CONCLUSION: Ocular manifestations occur in all forms of AAV, especially in GPA. Clinicians should be mindful of the wide spectrum of ocular disease in AAV, caused by active vasculitis, disease-associated damage, and toxicities of therapy.

Added diagnostic yield of temporal artery magnetic resonance angiography in the evaluation of giant cell arteritis.

OBJECTIVES: Temporal artery magnetic resonance angiography (TAMRA) is a useful tool to investigate possible diagnoses of GCA. As acquired images also reveal other local structures, they may assist in finding alternative diagnoses when assessing for possible GCA. We sought to assess the utility of TAMRA in identifying other significant abnormalities either associated with a diagnosis of GCA or potentially mimicking a clinical presentation of GCA. METHODS: A retrospective cohort study was undertaken at St Joseph's Healthcare in Hamilton, Ontario, Canada between February 2007 and April 2020 and included patients who underwent TAMRA for a possible diagnosis of GCA. Patient demographics, diagnosis and imaging findings were extracted, and descriptive analysis of findings was performed. RESULTS: We included 340 individuals who underwent TAMRA for assessment of a potential diagnosis of GCA and had clinical information available; there were 126 (37.1%) diagnoses of GCA. Fourteen (4.1%) patients had findings on TAMRA that demonstrated an alternative diagnosis, findings were predominantly in the temporomandibular joint, orbit and meninges. Eighteen (14.3%) patients with GCA had intracranial vascular changes that were demonstrative of intracranial vasculitis; one stroke was attributed to intracranial GCA. CONCLUSIONS: TAMRA has proven utility in diagnosing GCA, and these data suggest that it also has utility in identifying alternative diagnoses to rule out the disease. Intracranial vasculitis was also seen in 14.3% of patients; the clinical impact of these findings is currently poorly understood and requires further study.

Hospitalised COVID-19 outcomes are predicted by hypoxaemia and pneumonia phenotype irrespective of the timing of their emergence.

Despite the known clinical importance of hypoxemia and pneumonia, there is a paucity of evidence for these variables with respect to risk of mortality and short-term outcomes among those hospitalised with COVID-19. OBJECTIVE: Describe the prevalence and clinical course of patients hospitalised with COVID-19 based on oxygenation and pneumonia status at presentation and determine the incidence of emergent hypoxaemia or radiographic pneumonia during admission. METHODS: A retrospective study was conducted using a Canadian regional registry. Patients were stratified according to hypoxaemia/pneumonia phenotype and prevalence. Clinical parameters were compared between phenotypes using χ2 and one-way Analysis of variance (ANOVA). Cox analysis estimated adjusted Hazard Ratios (HR) for associations between disease outcomes and phenotypes. RESULTS: At emergency department (ED) admission, the prevalence of pneumonia and hypoxaemia was 43% and 50%, respectively, and when stratified to phenotypes: 28.2% hypoxaemia+/pneumonia+, 22.2% hypoxaemia+/pneumonia-, 14.5% hypoxaemia-/pneumonia+ and 35.1% hypoxaemia-/pneumonia-. Mortality was 31.1% in the hypoxaemia+/pneumonia- group and 26.3% in the hypoxaemia+/pneumonia+ group. Hypoxaemia with pneumonia and without pneumonia predicted higher probability of death. Hypoxaemia either <24 hours or ≥24 hours after hospitalisation predicted higher mortality and need for home oxygen compared with those without hypoxaemia. Patients with early hypoxaemia had higher probability of Intensive care unit (ICU) admission compared with those with late hypoxaemia. CONCLUSION: Mortality in COVID-19 infection is predicted by hypoxaemia with or without pneumonia and was greatest in patients who initially presented with hypoxaemia. The emergence of hypoxaemia was predicted by radiographic pneumonia. Patients with early and emergent hypoxaemia had similar mortality but were less likely to be admitted to ICU. There may be delayed identification of hypoxaemia, which prevents timely escalation of care.

The predictive utility of functional status at discharge: a population-level cohort analysis.

BACKGROUND: Functional status is a patient-important, patient-centered measurement. The utility of functional status measures to inform post-discharge patient needs is unknown. We sought to examine the utility of routinely collected functional status measures gathered from older hospitalized patients to predict a panel of post-discharge outcomes. METHODS: In this population-based retrospective cohort study, Adults 65+ discharged from an acute hospitalization between 4 November 2008 and 18 March 2016 in Ontario, Canada and received an assessment of functional status at discharge using the Health Outcomes for Better Information and Care tool were included. Multivariable regression analysis was used to determine the relationship between functional status and emergency department (ED) re-presentation, hospital readmission, long term care facility (LTCF) admission or wait listing ('LTCF readiness'), and death at 180 days from discharge. RESULTS: A total of 80 020 discharges were included. 38 928 (48.6%) re-presented to the ED, 24 222 (30.3%) were re-admitted, 5 037 (6.3%) were LTCF ready, and 9 047 (11.3%) died at 180 days. Beyond age, diminished functional status at discharge was the factor most associated with LTCF readiness (adjusted Odds Ratio [OR] 4.11 for those who are completely dependent for activities of daily living compared to those who are independent; 95% Confidence Interval [CI]: 3.70-4.57) and death (OR 3.99; 95% CI: 3.67-4.35). Functional status also had a graded relationship with each outcome and improved the discriminability of the models predicting death and LTCF readiness (p<0.01) but not ED re-presentation or hospital re-admission. CONCLUSION: Routinely collected functional status at discharge meaningfully improves the prediction of long term care home readiness and death. The routine assessment of functional status can inform post-discharge care and planning for older adults.

Functional recovery following hospitalisation of patients diagnosed with COVID-19: a protocol for a longitudinal cohort study.

INTRODUCTION: COVID-19 is an international public health crisis with more than 132 million infections worldwide. Beyond acute infection, emerging data indicate patients diagnosed with COVID-19 may experience persistent sequelae similar to survivors of sepsis or acute respiratory syndromes, including mobility limitations and fatigue. However, there is limited evidence on the trajectory of functional recovery in those hospitalised with COVID-19. The primary aim of the Coronavirus Registry Functional Recovery (COREG-FR) study is to understand the trajectory of functional recovery among individuals hospitalised for COVID-19 over the medium (up to 6 months) and longer term (6-12 months) that will guide clinical care and optimal management of serious COVID-19 illness and recovery. METHODS AND ANALYSIS: COREG-FR is a multicentre longitudinal cohort study. We will enrol a minimum of 211 adults age 18 years and older with COVID-19 from five hospitals. Participants will be followed from admission to hospital as an inpatient, to hospital discharge, and at 3-month, 6-month, 9-month and up to 12-month post-hospital discharge. We will conduct telephone interviews at ward admission and discharge, and telephone interviews plus in-person assessments of physical function and lung function at all remaining follow-ups. Our primary outcome is the Activity Measure for Post-Acute Care mobility scale measured at all time points. We will conduct linear mixed effects regression analyses to explore determinants of functional outcomes after COVID-19 illness. Subgroup analyses based on age (≤65 vs >65 years), frailty status (Clinical Frailty Scale score ≤4 vs >5) and variants of concern will be conducted. ETHICS AND DISSEMINATION: COREG-FR has been approved by Research Ethics Boards at participating sites. We will disseminate this work through peer-reviewed manuscripts, presentations at national and international meetings and through the established COREG website (www.coregontario.ca). COREG-FR is designed as a data platform for future studies evaluating COVID-19 recovery. TRIAL REGISTRATION NUMBER: NCT04602260; Pre-results.

Correction: Associations between continuity of primary and specialty physician care and use of hospital-based care among community-dwelling older adults with complex care needs.

[This corrects the article DOI: 10.1371/journal.pone.0234205.].

Value of second opinion subspecialty radiology consultation in suspected abdominal medium vessel vasculitis.

PURPOSE: To perform a descriptive analysis of individuals with suspected Polyarteritis nodosa (PAN) referred for second opinion imaging consultation. METHODS: A retrospective observational cohort study was performed at a single institution. A consecutive sample was performed of individuals who underwent a second opinion CT or MR angiography subspecialty radiologist consultation between January 2008 and September 2019 for suspected abdominal medium vessel vasculitis. Demographic, clinical, and imaging data were collected. Clinical and imaging findings were reported for PAN, small vessel vasculitis, and "non-vasculitis" groups. Agreement and diagnostic accuracy between final clinical and second opinion imaging diagnoses for PAN were determined. Two-tailed t-tests with a significant p-value < 0.05 were utilized. RESULTS: Of the 58 participants, 9 were clinically diagnosed with PAN, 11 with small vessel vasculitis (including lupus, IgA, and ANCA-associated vasculitis), and 38 with non-vasculitis diagnoses. The non-vasculitis group included 15 SAM, 3 FMD, and 1 SAM-FMD spectrum diagnoses. Higher C-reactive protein level (51 vs 17, p = 0.04) and superior mesenteric artery involvement (56% vs 21%, p = 0.04) were more common in PAN than non-vasculitis diagnoses, while arterial dissection (40% vs 0%, p = 0.02) and celiac vasculature involvement (53% vs 0%, p = 0.003) were more common in the non-vasculitis group. There was 88% agreement (51/58; Cohen's kappa 0.56); sensitivity was 67% [95%-confidence interval (CI) 30-93%] and specificity was 92% (95%-CI 80-98%). CONCLUSION: Isolated celiac artery involvement and arterial dissection were more common in non-inflammatory vasculopathies than PAN. Our findings highlight the need for multidisciplinary collaboration and awareness of the diverse findings of abdominal vasculopathies.

External validation of the 4C mortality score among COVID-19 patients admitted to hospital in Ontario, Canada: a retrospective study.

Risk prediction scores are important tools to support clinical decision-making for patients with coronavirus disease (COVID-19). The objective of this paper was to validate the 4C mortality score, originally developed in the United Kingdom, for a Canadian population, and to examine its performance over time. We conducted an external validation study within a registry of COVID-19 positive hospital admissions in the Kitchener-Waterloo and Hamilton regions of southern Ontario between March 4, 2020 and June 13, 2021. We examined the validity of the 4C score to prognosticate in-hospital mortality using the area under the receiver operating characteristic curve (AUC) with 95% confidence intervals calculated via bootstrapping. The study included 959 individuals, of whom 224 (23.4%) died in-hospital. Median age was 72 years and 524 individuals (55%) were male. The AUC of the 4C score was 0.77, 95% confidence interval 0.79-0.87. Overall mortality rates across the pre-defined risk groups were 0% (Low), 8.0% (Intermediate), 27.2% (High), and 54.2% (Very High). Wave 1, 2 and 3 values of the AUC were 0.81 (0.76, 0.86), 0.74 (0.69, 0.80), and 0.76 (0.69, 0.83) respectively. The 4C score is a valid tool to prognosticate mortality from COVID-19 in Canadian hospitals and can be used to prioritize care and resources for patients at greatest risk of death.

Incidence and Outcomes of Acute Kidney Injury in Patients Admitted to Hospital With COVID-19: A Retrospective Cohort Study.

BACKGROUND: The incidence of acute kidney injury (AKI) in patients with COVID-19 and its association with mortality and disease severity is understudied in the Canadian population. OBJECTIVE: To determine the incidence of AKI in a cohort of patients with COVID-19 admitted to medicine and intensive care unit (ICU) wards, its association with in-hospital mortality, and disease severity. Our aim was to stratify these outcomes by out-of-hospital AKI and in-hospital AKI. DESIGN: Retrospective cohort study from a registry of patients with COVID-19. SETTING: Three community and 3 academic hospitals. PATIENTS: A total of 815 patients admitted to hospital with COVID-19 between March 4, 2020, and April 23, 2021. MEASUREMENTS: Stage of AKI, ICU admission, mechanical ventilation, and in-hospital mortality. METHODS: We classified AKI by comparing highest to lowest recorded serum creatinine in hospital and staged AKI based on the Kidney Disease: Improving Global Outcomes (KDIGO) system. We calculated the unadjusted and adjusted odds ratio for the stage of AKI and the outcomes of ICU admission, mechanical ventilation, and in-hospital mortality. RESULTS: Of the 815 patients registered, 439 (53.9%) developed AKI, 253 (57.6%) presented with AKI, and 186 (42.4%) developed AKI in-hospital. The odds of ICU admission, mechanical ventilation, and death increased as the AKI stage worsened. Stage 3 AKI that occurred during hospitalization increased the odds of death (odds ratio [OR] = 7.87 [4.35, 14.23]). Stage 3 AKI that occurred prior to hospitalization carried an increased odds of death (OR = 5.28 [2.60, 10.73]). LIMITATIONS: Observational study with small sample size limits precision of estimates. Lack of nonhospitalized patients with COVID-19 and hospitalized patients without COVID-19 as controls limits causal inferences. CONCLUSIONS: Acute kidney injury, whether it occurs prior to or after hospitalization, is associated with a high risk of poor outcomes in patients with COVID-19. Routine assessment of kidney function in patients with COVID-19 may improve risk stratification. TRIAL REGISTRATION: The study was not registered on a publicly accessible registry because it did not involve any health care intervention on human participants.

Contextualizing temporal arterial magnetic resonance angiography in the diagnosis of giant cell arteritis: a retrospective cohort study.

OBJECTIVES: Imaging modalities have become common in evaluating patients for a possible diagnosis of GCA. This study seeks to contextualize how temporal arterial magnetic resonance angiography (TA-MRA) can be used in facilitating the diagnosis of GCA. METHODS: A retrospective cohort study was performed on patients who had been previously referred to a rheumatologist for evaluation of possible GCA in Hamilton, Ontario, Canada. Data including clinical features, inflammatory markers, imaging, and biopsy results were extracted. Multivariable logistic regression model to predict the diagnosis of GCA. Using these models, the utility of TA-MRA in series with or in parallel to clinical evaluation was demonstrated across the cohort as well as in subgroups defined by biopsy and imaging status. RESULTS: In total 268 patients had complete data. Those diagnosed with biopsy- and/or imaging-positive GCA were more likely to demonstrate classic features including jaw claudication and vision loss. Clinical multivariable modelling allowed for fair discriminability [receiver operating characteristic (ROC) 0.759, 95% CI: 0.703, 0.815] for diagnosing GCA; there was excellent discriminability in facilitating the diagnosis of biopsy-positive GCA (ROC 0.949, 0.898-1.000). When used in those with a pre-test probability of 50% or higher, TA-MRA had a positive predictive value of 93.0%; in those with a pre-test probability of 25% or less TA-MRA had a negative predictive value of 89.5%. CONCLUSION: In those with high disease probability, TA-MRA can effectively rule in disease (and replace temporal artery biopsy). In those with low to medium probability, TA-MRA can help rule out the disease, but this continues to be a challenging diagnostic population.

Supporting effective participation in health guideline development groups: The Guideline Participant Tool.

OBJECTIVES: Health guidelines are a key knowledge translation tool produced and used by numerous stakeholders worldwide. Effective participation in guideline development groups or development groups is crucial for guideline success, yet little guidance exists for members of these groups. In this study, we present the Guideline Participant Tool (GPT) to support effective participation in guideline groups, in particular those using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. STUDY DESIGN AND SETTING: We used a mixed methods and iterative approach to develop a tool to support guideline participation. We used the findings of a published systematic review to develop an initial list of items for considerations for guideline participants. Then, we refined this list through key informant interviews with guideline chairs, sponsors, and participants. Finally, we validated the GPT in three guideline groups with 26 guideline group members. RESULTS: The initial list of items based on 37 articles from the existing systematic review included 15 themes and 61 items for a draft tool. Ten key informant interviews helped us refine the list to include the following themes: selection of participants, guideline group process, and tool format. 26 respondents completed the validation survey from three guideline groups. Refinement of the tool ultimately generated a GPT with 33 items for participant consideration before, during, and in follow-up to guideline group meetings. CONCLUSION: The GPT contains helpful guidance for all guideline participants, particularly those without previous guideline experience. Future research should further explore the need for additional tools to support guideline participants and identify and develop strategies for improving guideline members' participation in guideline groups. This work will be incorporated into INGUIDE.org guideline training and credentialing efforts by the Guidelines International Network and McMaster University.