Table 3.

Covariate associations with transition probabilities

Covariate	OR (95% CI)
Year (reference: 2001–2004)
Effect on transition from low to moderate/severe disease
2005–2006	0.865 (0.700 to 1.068)
2007–2008	0.593 (0.471 to 0.746)
2009–2010	0.583 (0.474 to 0.716)
2011–2012	0.615 (0.506 to 0.748)
2013–2014	0.605 (0.497 to 0.735)
Effect on transition from moderate/severe to moderate/severe disease
2005–2006	1.055 (0.853 to 1.304)
2007–2008	0.911 (0.733 to 1.133)
2009–2010	0.824 (0.679 to 0.999)
2011–2012	0.888 (0.740 to 1.066)
2013–2014	1.004 (0.837 to 1.205)
Duration of RA (reference: 0 to 3 years)
Effect on transition from low to moderate/severe disease
3 to 10 years	0.777 (0.698 to 0.865)
>10 years	0.840 (0.752 to 0.939)
Effect on transition from moderate/severe to moderate/severe disease
3 to 10 years	1.167 (1.045 to 1.303)
>10 years	1.379 (1.236 to 1.539)
Age (reference: <50 years)a
50 to 64 years	1.176 (1.082 to 1.279)
≥65 years	1.024 (0.939 to 1.117)
Visit interval (reference: 3 to < 4 months)
Effect on transition from low to moderate/severe disease
4 to <5 months	1.057 (0.940 to 1.187)
5 to <6 months	1.085 (0.961 to 1.226)
6 to <7 months	1.201 (1.057 to 1.364)
7 to <8 months	1.349 (1.160 to 1.568)
8 to 9 months	1.171 (0.977 to 1.403)
Effect on transition from moderate/severe to moderate/severe disease
4 to <5 months	0.931 (0.831 to 1.042)
5 to <6 months	0.801 (0.712 to 0.902)
6 to <7 months	0.779 (0.686 to 0.886)
7 to <8 months	0.799 (0.683 to 0.935)
8 to 9 months	0.866 (0.729 to 1.028)

CI confidence interval, RA rheumatoid arthritis

^aNo interaction with prior state and age was noted so the effect was the same for the transition from low to moderate/severe and from moderate/severe to moderate/severe disease