Table 1

 Patient characteristics at baseline of patients that presented with rheumatoid arthritis, patients that presented with undifferentiated arthritis and developed rheumatoid arthritis after 1 year and patients that presented with undifferentiated arthritis and had other diagnosis than rheumatoid arthritis after one year follow-up

RA at 2 weeks (n = 276)UA→RA (n = 131)UA→non-RA (n = 355)p Value*
*Determined for UA→RA v UA→non-RA. Comparison of RA at two weeks v UA→RA showed no significant differences.
Anti-CCP+, anti-cyclic-citrullinated peptide positive; CRP, C reactive protein; RA, rheumatoid arthritis; RF+, rheumatoid factor positive; SE+, presence of one or two shared epitope alleles; TE+, current and past smokers as indicated in the medical history; UA, undifferentiated arthritis.
Age (years) (mean)585648<0.001
Female (%)666451NS
CRP (mg/l) mean)3529210.036
IgM RF+ (%)655213<0.001
Anti-CCP+ (%)54517< 0.01
SE+ (%)6863490.046
TE+ (%)475250NS