Patterns of biologic agent utilization among patients with rheumatoid arthritis: a retrospective cohort study

Table 5 Cox proportional hazards model of time-to-discontinuation (more than 60 day gap in days supply or start of non-index biologic agent) of anti-TNF therapy

	Overall (N = 3984)	p value	Etanercept (N = 1851)	p value	Adalimumab (N = 1393)	p value	Infliximab (N = 740)	p value
Subsequent anti-TNF (reference first anti-TNF)	1.177	< 0.001	1.121	0.133	1.238	0.002	1.140	0.214
Age (years)	0.990	< 0.001	0.989	< 0.001	0.987	< 0.001	1.004	0.325
Female (reference male)	0.884	0.006	0.827	0.005	0.870	0.063	1.066	0.529
Region (reference Northeast)
Midwest	0.954	0.545	0.874	0.218	1.005	0.973	1.198	0.386
South	1.016	0.829	0.886	0.222	1.066	0.618	1.366	0.113
West	0.930	0.370	0.791	0.043	1.095	0.520	1.068	0.758
Plan type (reference HMO)
PPO	0.985	0.821	1.039	0.697	0.875	0.232	1.128	0.493
POS	0.873	0.288	0.668	0.050	1.152	0.516	0.864	0.578
EPO	1.028	0.621	1.025	0.767	0.943	0.520	1.321	0.045
Indemnity	0.902	0.136	0.847	0.109	0.806	0.060	1.344	0.083
Baseline treatment
Methotrexate	0.836	< 0.001	0.871	0.013	0.832	0.003	0.801	0.014
NSAIDs	0.897	0.003	0.858	0.006	0.922	0.184	0.890	0.180
Corticosteroids	1.050	0.205	1.054	0.354	1.083	0.218	1.000	0.997
Baseline Charlson score	1.112	< 0.001	1.105	0.006	1.105	0.006	1.123	0.031

NSAID, non-steroidal anti-inflammatory drug; HMO, health maintenance organization; PPO, preferred provider organization; EPO, exclusive provider organization.

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