Table 2.

Exploration of potential risk factors for more erosive disease

Continuous variables	Mean difference (SE)†	GEE OR (95% CI)	p Value‡
Disease duration	+4.20 (1.60)	0.95 (0.91 to 0.98)	0.014
Age	+1.90 (1.80)	1.01 (0.96 to 1.08)	0.560
Baseline CRP	−0.02 (0.05)	0.99 (0.95 to 1.05)	0.970
Baseline ESR	+1.98 (2.10)	1.00 (0.99 to 1.00)	0.440
Dichotomous variables	OR* (95% CI)	GEE OR (95% CI)	p Value‡
Tender joints at baseline (N)	3.30 (1.40 to 7.60)	2.50 (1.10 to 5.70)	0.030
Palpable effusion at baseline	5.30 (2.30 to 12.0)	4.40 (2.10 to 8.80)	0.001
PIP joint vs DIP joint	1.50 (0.60 to 3.20)	0.12 (0.78 to 1.03)	0.790

^*OR and 95% CI obtained by GEE modelling (multivariate analysis).

^†For each item, the mean difference between groups with erosive and non-erosive disease were calculated (univariate analysis).

^‡p Values calculated by GEE modelling.

CRP, C-reactive protein; DIP, distal interphalangeal; ESR, erythrocyte sedimentation rate; GEE OR, generalised estimating equation odds ratio; PIP, proximal interphalangeal; SE, standard error of mean difference.