Table 1.

Methodological quality of included studies (after consensus was reached).

Authors	Study Population	Source Population	In-/exclusion Criteria	Valid OA Diagnosis	Relevant Prognostic Factors	Standardized/Valid Progn. Measurements	Presentation Prognostic Factors	Relevant Outcome Measures	Standardized/Valid Outcome Measurements	Presentation Outcome Measures	^#Multivariable Estimates	Cohen’s κ per Study
Gignac, 2008³⁰	+	+	+	−	+	+	+	+	+	+	+	NA (9/11)
Grotle, 2008²⁶	+	+	+	−	+	+	+	+	+	+	+	0.16
Merx, 2007²⁷	+	+	−	+	−	−	−	+	+	+	−	0.29
Rabenda, 2006³¹	−	+	−	−	+	+	+	+	+	−	−	1.0
Fautrel, 2005³³	+	+	+	+	+	+	+	+	+	+	−	0.74
Gupta, 2005³⁴	+	+	−	+	+	+	+	+	−	+	−	0.31
Leardini, 2004³⁵	−	+	+	+	+	+	+	+	−^*	−^*	−	0.35
Maetzel, 2004³⁶	−	+	+	+	+	+	+	+	+	+	−	0.62
Woo, 2003³⁷	−	+	−	+	+	−	+	+	+	+	−	1.0
Lerner, 2002³²	−	+	+	+	+	+	+	+	+	+	+	0.30
Gabriel, 1997³⁸	−	+	−	+	−	−	−	+	+	+	−	0.79
Mäkelä, 1993²⁸	+	+	+	+	+	+	+	+	+	+	+	NA (8/11)
Pincus, 1989²⁹	+	+	+	−	+	+	+	+	+	+	−	NA (8/11)
Julkunen, 1981³⁹	−	+	+	+	+	+	+	+	+	+	−	0.56

↵* Outcome measures presented, but unclear and difficult to control. Values in parentheses. NA: not applicable — κ could not be calculated because one of the authors rated only positive scores; OA: osteoarthritis.