Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Blinded Multi-Rater Evaluation of Diagnosis and Candidate Classification Criteria for Polymyalgia Rheumatica (PMR). ACREULAR Study Group for Development of Classification Criteria for PMR.

Matteson5,  Eric L., Cimmino7,  Marco A., Maradit-Kremers1,  Hilal, Salvarani8,  Carlo, Schirmer3,  Michael, Schmidt13,  Wolfgang A., Cid12,  Maria C.

Department of Health Sciences Research, Mayo Clinic, Rochester, MN
Department of Rheumatology, Medical University, Graz, Graz, Austria
Department of Rheumatology, Southend University Hospital, Essex, United Kingdom
Department of Systemic Autoimmune Hospital Clinic Provincial, Barcelona, Spain
Immanuel Krankenhaus Berlin: Medical Center for Rheumatology Berlin-Buch Berlin, Berlin, Germany
National Institute of Rheumatology and Physiotherapy, Budapest, Hungary
Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Oxford University, Oxford, UK
Rheumatology and Rehabilitation Research Unit, University of Leeds, Leeds, UK
Rheumatology Associates of North Jersey, Teaneck, NJ
Rheumatology Unit, Clinica e Terapia Medica Department, Sapienza Università di Roma, Policlinico Umberto I, Rome, Italy
Rheumatology Unit, Ospedale Misericordia e Dolce, Prato, Italy
Department of Internal Medicine and Rheumatology, WIM CSK MON, Warszawa, Poland
Service de Medecine Interne, Amiens, France
Servicio de Reumatología, Hospital Universitario Marques de Valdecilla, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
Department of Internal Medicine I, Medical University Innsbruck, Innsbruck, Austria
Department of Internal Medicine, Division of Rheumatology, Mayo Clinic, Jacksonville, FL
Department of Internal Medicine, Division of Rheumatology, Mayo Clinic, Rochester, MN
Department of Internal Medicine, Division of Rheumatology, Mayo Clinic, Scottsdale, AZ
Department of Internal Medicine, University of Genova, Genova, Italy
Department of Rheumatology, Arcispedale S. Maria Nuova, Reggio Emilia, Italy
Department of Rheumatology, Marmara University Medical School, Istanbul, Turkey

Objective:

To assess multi-rater discrimination of polymyalgia rheumatica (PMR) from other conditions mimicking PMR.

Methods:

A total of 23 investigators were asked to blindly rate 10 PMR cases and 20 controls derived from a large prospective study of candidate criteria for PMR. Investigators were asked to review the clinical features, examination findings (ie restricted shoulder/hip movement, synovitis), inflammatory markers (ESR/CRP), serology for RF and anti-CCP, the steroid response (categorized as rapid, complete, sustained). Each criteria was rated on a 5-point scale reflecting the degree of confidence of a PMR diagnosis (1=strongly influences diagnosis of PMR to 5=strongly influences the diagnosis was not PMR). After all criteria were rated, investigators were asked to provide a diagnosis of PMR or other condition and indicate whether they would enter such a subject in a clinical trial for PMR. To assess the diagnostic accuracy of each candidate criteria, the mean rating across all raters was taken. This composite score was then used to determine the areas under the ROC curve (AUC), denoted as the c-statistic. Patients were categorized into 3 groups based on raters' misclassification rates. Group 1: greater than 50% misclassified; Group 2: 20–50% misclassified, Group 3: less than 20% misclassified.

Results:

Missclassification proportion was >=20% in 10 patients. Factors that contributed to misclassification in Group 1 (n=3, 1 case, 2 controls) were normal ESR and/or CRP, poor or ill- sustained steroid response and RF positivity without peripheral synovitis. In Group 2 (n=7: 4 cases, 3 controls), misclassification was related to persistent synovitis, no complete/sustained steroid response, RF or CCP positivity and low baseline ESR and/or CRP. The AUC c-statistic suggested that gender, duration of symptoms, systemic symptoms such as weight loss, neck pain, limitation of movement and serum electrophoresis were unhelpful in discriminating cases from controls (c-statistic < 0.8 in all). Bilateral hip pain, morning stiffness, ESR and CRP levels (pre and especially post steroid), steroid response were good discriminators of cases from controls (c-statistic > 0.8 in all, table).

Candidate CriteriaPMR Cases M (SD)Controls M (SD)P value*C-statistic95% CIC-Statistic
Bilateral pelvic girdle aching1.8 (1.1)3.3 (1.1)0.010.80(0.54, 0.92)
Morning stiffness >45 min1.7 (1.0)3.0 (1.4)<0.010.87(0.63, 0.96)
Abnormal CRP at baseline1.8 (0.9)3.2 (1.4)<0.010.81(0.58, 0.92)
Abnormal ESR at 26 weeks2.3 (1.0)3.2 (0.8)<0.010.89(0.64, 0.97)
Abnormal CRP at 26 weeks2.2 (0.9)3.1 (1.1)<0.010.85(0.62, 0.94)
Rapid steroid response2.6 (1.5)4.6 (0.6)<0.010.99(0.90, 1.00)
Complete steroid response2.2 (1.4)4.5 (0.7)<0.010.98(0.84, 1.00)
Sustained steroid response2.6 (1.4)4.3 (0.7)<0.010.99(0.90, 1.00)
*P value from a Wilcoxon rank sum test for difference in rating scores between PMR cases and controls. Scores tested are mean score across the 23 raters, further averaged by case (n = 10) and control (n = 20).

Conclusions:

The verification exercise showed the stepped diagnostic process and most candidate criteria items performed well in discriminating PMR cases from controls. However, a significant proportion of cases/controls were difficult to classify. Questions such as whether PMR may not always adequately respond to steroids and whether polymyalgic RF positive disease without peripheral synovitis can occur need further investigation.

To cite this abstract, please use the following information:
Matteson, Eric L., Cimmino, Marco A., Maradit-Kremers, Hilal, Salvarani, Carlo, Schirmer, Michael, Schmidt, Wolfgang A., et al; Blinded Multi-Rater Evaluation of Diagnosis and Candidate Classification Criteria for Polymyalgia Rheumatica (PMR). ACREULAR Study Group for Development of Classification Criteria for PMR. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1652
DOI: 10.1002/art.29417

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