2015 Gout Classification Criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative.
OBJECTIVE
Existing criteria for the classification of gout have suboptimal sensitivity and/or specificity, and were developed at a time when advanced imaging was not available. The current effort was undertaken to develop new classification criteria for gout.


METHODS
An international group of investigators, supported by the American College of Rheumatology and the European League Against Rheumatism, conducted a systematic review of the literature on advanced imaging of gout, a diagnostic study in which the presence of monosodium urate monohydrate (MSU) crystals in synovial fluid or tophus was the gold standard, a ranking exercise of paper patient cases, and a multicriterion decision analysis exercise. These data formed the basis for developing the classification criteria, which were tested in an independent data set.


RESULTS
The entry criterion for the new classification criteria requires the occurrence of at least 1 episode of peripheral joint or bursal swelling, pain, or tenderness. The presence of MSU crystals in a symptomatic joint/bursa (i.e., synovial fluid) or in a tophus is a sufficient criterion for classification of the subject as having gout, and does not require further scoring. The domains of the new classification criteria include clinical (pattern of joint/bursa involvement, characteristics and time course of symptomatic episodes), laboratory (serum urate, MSU-negative synovial fluid aspirate), and imaging (double-contour sign on ultrasound or urate on dual-energy computed tomography, radiographic gout-related erosion). The sensitivity and specificity of the criteria are high (92% and 89%, respectively).


CONCLUSIONS
The new classification criteria, developed using a data-driven and decision analytic approach, have excellent performance characteristics and incorporate current state-of-the-art evidence regarding gout.
Boston University School of Medicine, Boston, Massachusetts.
Tuhina
T
Neogi
Viecuri Medical Center, Venlo, The Netherlands, and Radboud University Medical Center, Nijmegen, The Netherlands.
Tim L Th A
TL
Jansen
University of Auckland, Auckland, New Zealand.
Nicola
N
Dalbeth
Radboud University Medical Center, Nijmegen, The Netherlands.
Jaap
J
Fransen
University of Pennsylvania, Philadelphia.
H Ralph
HR
Schumacher
Radboud University Medical Center, Nijmegen, The Netherlands.
Dianne
D
Berendsen
University of Otago, Wellington, New Zealand.
Melanie
M
Brown
Boston University School of Medicine, Boston, Massachusetts.
Hyon
H
Choi
University of Florida, Gainesville.
N Lawrence
NL
Edwards
Radboud University Medical Center, Nijmegen, The Netherlands.
Hein J E M
HJ
Janssens
Frédéric Lioté, MD, PhD: INSERM UMR 1132, Hôpital Lariboisière, AP-HP, and Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
Frédéric
F
Lioté
McMaster University Medical Centre, Hamilton, Ontario, Canada.
Raymond P
RP
Naden
University of Edinburgh, Edinburgh, UK.
George
G
Nuki
University of Pennsylvania, Philadelphia.
Alexis
A
Ogdie
Hospital Universitario Cruces and BioCruces Health Research Institute, Vizcaya, Spain.
Fernando
F
Perez-Ruiz
University of Alabama at Birmingham.
Kenneth
K
Saag
Birmingham VA Medical Center and University of Alabama at Birmingham, and Mayo Clinic College of Medicine, Rochester, Minnesota.
Jasvinder A
JA
Singh
Gilead Sciences, Foster City, California).
John S
JS
Sundy
University Hospital Carl Gustav Carus, Dresden, Germany.
Anne-Kathrin
AK
Tausche
Hospital General de Mexico, Mexico City, Mexico.
Janitzia
J
Vazquez-Mellado
Janitzia
J
Vaquez-Mellado
University of Michigan Health System, Chelsea.
Steven A
SA
Yarows
University of Otago, Wellington, New Zealand.
William J
WJ
Taylor
D018771:Arthralgia / Q000175:diagnosis; D005060:Europe; D006073:Gout / Q000145:classification* / Q000175:diagnosis*; D006801:Humans; D013582:Synovial Fluid / Q000737:chemistry; D014481:United States; D014527:Uric Acid / Q000032:analysis
D014527:Uric Acid