This is the peer reviewed version of the following article: Druce, KL, Jones, GT, Macfarlane, GJ & Basu, N 2015, 'Determining Pathways to Improvements in Fatigue in Rheumatoid Arthritis: Results From the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis' Arthritis & Rheumatology, vol 67, no. 9, pp. 2303-2310., which has been published in final form at doi: 10.1002/art.39238. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.