Table 3

Percent pseudo-R ² statistics for unadjusted univariate models of sensitivity, specificity, univariate model of Youden’s index and bivariate model of sensitivity and specificity (n=148)

Case definition criteria	Univariate model sensitivity	Univariate model specificity	Univariate model Youden’s index	Bivariate model
Physician diagnoses	28.8*	36.9*	82.6*	19.2*
Physician diagnosis observation time	25.2*	28.9*	77.4*	16.0*
Specialist diagnoses	0.6	2.1*	25.5*	8.0*
≥60 days between physician diagnoses	1.4*	1.9*	9.2*	7.7*
Exclusion criteria A	4.1*	1.3	12.7*	9.5*
Exclusion criteria B	3.1*	1.1	9.7*	7.0*
Hospital diagnoses	1.0	0.7	3.1	1.3*
ER diagnoses	0.2	0.02	13.9*	1.3
RA-related medications, excluding steroids	2.4*	4.5*	0.6	1.9
RA-related medications, including steroids	1.2	0.2	0.4	0.8

Exclusion criteria A excluded individuals with 2+ physician diagnosis codes with a different rheumatology diagnosis than an RA diagnosis; exclusion criteria B excluded individuals whose RA diagnosis was not confirmed by a specialist.
*Indicate estimates that were statistically significant at α=0.01.
ER, emergency room; RA, rheumatoid arthritis.