Response to Tumor Necrosis Factor Inhibitors in Rheumatoid Arthritis for Function and Pain is Affected by Rheumatoid Factor

OBJECTIVES To investigate differences in response to tumor necrosis factor inhibitor treatment (TNFi) in seropositive (rheumatoid factor positive; RF+) versus seronegative (RF-) patients with established RA as measured by the Health Assessment Questionnaire Disability Index (HAQ-DI) and pain. METHODS RA patients from an established RA cohort were studied according to rheumatoid factor (RF) status for change in HAQ-DI and pain (0-3 VAS) one year after starting treatment with a TNFi. RESULTS There were 238 patients treated with TNFi who had follow-up data (178 RF+ and 60 RF-). Disease duration was longer in RF+ vs RF- (12+8 vs 8+8 years) but the proportion of females (82% vs 72%, P=0.7), baseline HAQ-DI (1.44+0.63 vs 1.41+0.63, P=0.8) and pain (1.92+0.67 vs 1.93+0.67, P=0.9) were not different. The mean duration of treatment of first TNFi was 2.8 vs 2.3 years, P=0.1 and 68% of RF+ vs 62% of RF- were still receiving first TNFi at last visit (P=0.5). For patients with data at baseline and one year, the one-year HAQ-DI change was significantly greater in 90 RF+ patients (-0.356) versus 38 RF- patients (-0.126; P=0.04). The mean pain improvement was also greater in 77 RF+ vs 32 RF- patients (-0.725 vs -0.332 respectively; P=0.03). Numbers are small, data are missing and comorbidities, DAS28 and anti-CCP were not collected. CONCLUSION Despite limitations in the data, in established RA after failure of DMARDs, RF+ patients may be more responsive to TNFi therapy as measured by changes in HAQ-DI and pain. INNOVATION There may be a better response to TNFi in RA if RF positive for function and pain.