Table 1 Demographic and clinical data of the patients.

Age at IP onset, years, mean (SD)	55 (16)
Sex: female (%)	1410 (67)
Met cumulative ACR RA criteria after 5 years, yes (%)	1239 (59)
Ever positive for rheumatoid factor, yes (%)*	681 (35)
Smoking history at first assessment, current smoker (%)†	521 (26)
Smoking history at first assessment, past (only) smoker (%)†	772 (39)
Steroid use before first admission, ever (%)	530 (25)
DMARD use before first admission, ever (%)	979 (46)
Erosive joints, ever (%)‡	695 (48)
Initial HAQ, mean (SD)	0.85 (0.74)
Fifth assessment HAQ, mean (SD)	0.84 (0.71)
Mean HAQ, mean (SD)	0.84 (0.72)

ACR, American College of Rheumatology; DMARD, disease‐modifying antirheumatic drugs; HAQ, Health Assessment Questionnaire; IP, inflammatory polyarthritis; RA, rheumatoid arthritis.

*Based on 93% complete data.

†Based on 94% complete data.

‡Based on 68% complete data.