Joint tenderness and swelling in biologic-treated inflammatory arthritis patients - a tricky trade off?

Objective: To compare the pattern of joint responses in patients with rheumatoid arthritis and psoriatic arthritis treated with TNF inhibitor (TNFi) therapy.

Methods: A total of 182 PsA/Rheumatoid arthritis (RA) patients attending the rheumatology unit of a tertiary referral centre in Ireland were recruited and prospectively followed up by the attendant rheumatologists. Clinical progress of the patients was noted at baseline and 6 months after starting TNFi therapy.

Results: A total of 114 RA and 68 PsA patients were assessed; 20% of the patients had one of either tender joints or swollen joints after 6 months of therapy. Rheumatoid arthritis patients had a significantly higher proportion of non-tender swollen joints compared with PsA patients, whereas PsA patients had a higher proportion of tender non-swollen joints (p < 0.05).

Conclusions: Residual joint swelling was found more commonly in RA patients than in PsA patients following TNFi therapy, whereas residual tender joints occurred more frequently in PsA; this may reflect enthesiopathy or periostitis.