Table 5.

Multiple linear regression model of baseline variables on followup DAS28 scores. Baseline variables: sex, age, smoking history, presence of erosions, DAS28 score, HAQ score, SJC, ESR, CRP, and treatment with DMARD and/or biologic agents. R² is the total variance explained in the model. β values are standardized coefficients.

Variables	β	p
12-mo followup
Seronegative	0.111	0.3811
Baseline HAQ	1.219	< 0.0001
Baseline ESR	0.016	< 0.001
Baseline CRP	−0.009	0.0087
24-mo followup
Seronegative	−0.121	0.4736
Age	0.014	0.0063
Baseline DAS28	0.243	0.0001
Baseline HAQ	0.896	< 0.0001
Baseline SJC28	−0.045	0.0062
Biologics at baseline	1.162	0.0031
R²	0.275	—

DAS28: 28-joint Disease Activity Score; HAQ: Health Assessment Questionnaire; SJC28: swollen joint count at 28 joints; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; DMARD: disease-modifying antirheumatic drug.