Table 2.

Characteristics of the included studies.

Study	Index Studied	Disease Severity Comparator	Claims-based Variables	Adjusted Measure of Association
Study	Index Studied	Disease Severity Comparator	Claims-based Variables	Correlation to RARBIS with Medication Subscale	Correlation to RARBIS without Medication Subscale
Ting, 2008²⁴	CIRAS	RARBIS	Age and sex	0.08	0.05
			Rheumatology visits	0.01	—
			Rehabilitation visits	0.01	0.04
			Felty’s syndrome	0.01	0.03
			No. inflammatory markers ordered	0.14	0.08
			Rheumatoid factor test ordered	0.02	0.04
			No. platelet counts ordered	0.03	0.01
			No. chemistry panels ordered	0.01	0.02
			Composite CIRAS score	0.56 (p < 0.0001)	0.51 (p < 0.0001)
Wolfe, 2006³⁰	Composite score for RA severity index	PAS	Age	AUC = 0.64	AUC = 0.70
			Sex	For detection of PAS above or below median value for cohort	For detection of 1st vs 4th PAS quartile for cohort
			Disease duration
			Current DMARD and/or biologics
			Lifetime number of DMARD and/or biologics

AUC: Area under the curve; CIRAS: claims-based index for RA severity; PAS: Patient Activity Score; RARBIS: RA medical records-based index of severity; RA: rheumatoid arthritis; DMARD: disease-modifying antirheumatic drug.