Foot and ankle problems in patients with rheumatoid arthritis in 2019: still an important issue

OBJECTIVE: To study the prevalence of foot pain in patients with rheumatoid arthritis (RA) and whether including a 12-joint foot count in addition to the 28-joint count (from the Disease Activity Score 28 [DAS28]) improved detection of foot or ankle pain. In addition, the association between the self-reported foot and ankle score (SEFAS), patient-reported function, and disease-specific factors was studied.

METHODS: Physician-reported data (swollen/tender 12-joint foot count, DAS28, and medication) and patient-reported data (foot/ankle pain, physical function, global health, and SEFAS) were assessed during a clinical visit. Data were analyzed with t test, χ 2 tests, and regression analysis.

RESULTS: A total of 320 patients with RA were included (mean age 63 years, SD 13 years; 73% women), of whom 69% reported foot or ankle pain. Patients who reported foot or ankle pain had a lower mean age and worse disease activity, general pain, function, and global health (P ≤ 0.016), and fewer were in remission (50% versus 75%; P < 0.001) compared with patients without foot pain. The 12-joint foot count identified 3.2% and 9.5% additional patients with swollen and tender joints, respectively, compared with the 28-joint count. The SEFAS was associated with walking problems (β = -2.733; 95% confidence interval [CI] = -3.963 to -1.503) and worse function (β = -3.634; 95% CI = -5.681 to -1.587) but not with joint inflammation severity.

CONCLUSION: The prevalence of foot or ankle pain in patients with RA is high. The 12-joint foot count had minor effects on detecting patients with foot pain. However, the SEFAS contributed additional information on foot problems that was not identified by joint examinations alone.