Table 1 Baseline characteristics in 136 included patients with rheumatoid arthritis (RA) and the 102 non-participants (mean (SD) values for continuous variables (also median and range for vdH Sharp score and DXR-BMD), percentages for counts)

	Patients included in study (n = 136)	Patients not included in study (n = 102)*
Age (years)	51.3 (12.1)	52.8 (14.2)
Female	76	71
Positive anti-CCP	62	59
Positive IgM RF	48	48
Disease duration (years)	2.2 (1.2)	2.4 (1.1)
CRP (mg/litre)	9.4 (12.2)	11.0 (13.4)
ESR (mm/h)	26.2 (20.9)	25.5 (18.3)
HAQ score (scale 0–3)	0.9 (0.6)	1.0 (0.7)
Current users of corticosteroids	26	29
Current users of DMARDs	54	49
vdH Sharp score	6.8 (12.2)	NA
	2.0 (0–69.0)
Hand DXR-BMD (g/cm²)	0.55 (0.09)	NA
	0.55 (0.33–0.77)

*All group comparisons p>0.05.
CCP, cyclic citrullinated peptide; CRP, C-reactive protein; DMARD, disease-modifying antirheumatic drug; DXR-BMD, digital x ray radiogrammetry bone mineral density; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire; NA, not available; RF, rheumatoid factor; vdH Sharp, van der Heijde modification of the Sharp score.