Table 4.

Continuation and Initiation Rates of Infliximab Use in 2006 Relative to Prior Years

Year	Infliximab users in base year (N)	Continuation rate in follow-up year	Claims per user among continuers in follow-up year	Non-users of infliximab in base year (N)	Initiation rate in follow- up year	Claims per user among new user in follow-up year
2002 to 2003	26,260	79.8%	6.0	510,920	1.8%	4.4
2003 to 2004	33,040	79.6%	6.1	536,680	1.4%	4.8
2004 to 2005	36,460	79.7%	6.1	542,320	1.1%	4.4
2005 to 2006	35,840	82.3%	6.2	544,080	1.1%	4.5

Note: At 5% level, there were no significant differences in the rates of use or the number of claims per user across the four longitudinal cohorts. Analysis of the 2005–06 longitudinal cohort indicated that only 3% and 2% of infliximab users in 2005 switched to abatacept and rituximab in 2006, respectively (Appendix 1).