Background: Causes of RA associated pain include synovitis, secondary fibromyalgia and osteoarthritis, and depression. NSAIDs, steroids, DMARDs and biologics treat inflammatory joint pain. RA patients often require additional analgesics. The literature suggests that up to one third of RA patients have depression. TNF therapies have resulted in marked improvements in RA response criteria and patient reported outcomes. TNF agents also reduce the need for chronic steroids. It is not clear whether TNF therapies result in less analgesic and antidepressant use.
Objectives: To assess the “real world” use of comedications (analgesics and antidepressants) to treat pain in RA patients treated with (a) MTX without TNF therapies (MTX cohort) and (b) TNF therapies (etanercept, infliximab, adalimumab) with or without MTX (TNF cohort) using a US healthcare claims database.
Methods: A retrospective analysis was performed using PharMetric’s managed care administrative claims from 2000–2005. An index date was defined for each cohort as the first observed MTX or TNF claim with a prior RA diagnosis. Patients were included if they had continuous plan eligibility for 12 months prior to and post index. The presence of prescription claims for each comedication for a patient in the 12 months pre and post index was ascertained. For each comedication, the proportion of patients with comedication claims pre and post index was tested for each cohort.
Results: 1811 patients (76% F, mean age 49) comprised the MTX cohort; 71% (1311) were taking comedications at any time pre or post index. 1380 patients formed the TNF cohort (74% F, mean age 48); 72% (994) took comedications at any time pre or post index. 80% of the TNF group was taking MTX. The table shows comedication prescription claims for 2000–2005 (up to 12 months pre and post index date). At initiation, 1072 (58%) and 833 (60%) of patients were on comedications in the MTX and TNF cohorts, respectively. At 1 Year, 1026 (56%) and 786 (57%) of patients were on comedications in the MTX and TNF cohorts, respectively.
Table:

	MTX cohort n (%)	TNF cohort n (%)
ANTIDEPRESSANTS	252 (19)	207 (21)
Total use pre index	191 (15)	147 (15)
Used pre and post index	119 (9)	99 (10)
Used pre but not post index	72 (5)	48 (5)
p value	0.00	0.00
Total use post but not pre index	61 (5)	60 (6)
OPIOIDS	1191 (91)	917 (92)
Total use pre index	929 (71)	750 (75)
Used pre and post index	620 (47)	519 (52)
Used pre but not post index	309 (24)	231 (23)
p value	0.00	0.00
Total use post but not pre index	262 (20)	167 (16)
Acetaminophen,benzodiazepines,barbiturates & NMDA receptor antagonists; data not shown

Conclusion: Comedication use in RA patients taking MTX or TNF agents remains remarkably stable over time. Opioid and antidepressant use decreased significantly after starting MTX or a TNF agent. The percentage of patients using comedications was comparable in those treated with MTX (without biologics) and those treated with TNF agents. Comedication use after starting MTX or TNF agents remained similar for all comedications except for opioids. More patients starting MTX needed opioids than patients starting TNF agents (20 vs 16%); further investigation is pending to confirm this observation. Notwithstanding the limitations of patient claims data bases, these results suggest that the continued use of comedications for RA patients treated with MTX or TNF agents demands further study, as their use may reflect other painful processes in RA that are not effectively addressed with MTX alone or TNF agents.