Table 3.

Multivariable Adjusted Association between Absolute Disease Activity, Change in Disease Activity, and Calendar Time with Switching the Biologic Treatment Regimen within the first year (A total of 2,070 treatment episodes; 272 switched and 1,798 maintained treatment)

Covariates*	Odds Ratio and 95% Confidence Interval
Disease Activity (measured as Clinical
Disease Activity Index, or CDAI)
< 10 (mild)	Referent
10 – 22 (moderate)	1.94 (1.36 – 2.75)
≥ 22 (high)	3.39 (2.27 – 5.06)
Improvement in Disease Activity (change in CDAI from baseline)	1.02 (1.01–1.04)
Calendar Year
02 – 05	Referent
06 – 07	2.62 (1.64 – 4.19)
08 – 09	6.05 (3.72 – 9.86)
Number of Previous Anti-TNF agents used
0	Referent
1 or more	1.43 (1.08–1.89)
Timing of the follow-up visit
≤ 6 months	Referent
6–12 months	1.26 (0.93–1.69)

^*measured at the visit where the patient either switched or was maintained on therapy

^‡There was a significant clustering effect at physician level in the decision to switch (OR=1.32, 95% CI 1.16–1.95)