Factors associated with disability in patients with rheumatoid arthritis with persistent moderate disease activity: a retrospective cohort study

BACKGROUND: Many patients with rheumatoid arthritis (RA) do not attain remission/low disease activity, remaining in a moderate disease activity state (MDAS) with ongoing disability and impaired quality of life (QoL). If patients in persistent MDAS with poor future outcomes could be prospectively identified, they could arguably be treated more intensively. We evaluated baseline factors predicting function (Health Assessment Questionnaire-Disability Index [HAQ-DI] scores) and QoL (3-level EuroQol-5 dimensions questionnaire [EQ-5D-3L] index scores) at 12 months in patients with RA in persistent MDAS in a real-world setting. METHODS: Patients with persistent MDAS (Disease Activity Score for 28-joint count based on erythrocyte sedimentation rate [DAS28-ESR] 3.2–5.1 on at least two consecutive outpatient appointments over 12 months) were identified retrospectively from Guy’s Hospital RA Centre and analysed in two groups: (1) biologic naïve at baseline or (2) receiving/ever received biologics. The baseline timepoint was the second-visit MDAS DAS28-ESR score; the endpoint was the closest visit to 12 months. Linear regression analyses evaluated relationships between baseline variables and (1) 12-month HAQ-DI scores, (2) 12-month rank-transformed EQ-5D-3L index scores, (3) 12-month changes in HAQ-DI scores, and (4) 12-month changes in EQ-5D-3L index scores. RESULTS: The analysis included 207 biologic-naïve and 188 biologic-experienced patients. All patients had moderate disability (mean HAQ-DI 1.21 and 1.46) and impaired QoL (mean EQ-5D-3L index scores 0.52 and 0.50). Many reported moderate/severe pain (93 and 96%) and showed little change in HAQ-DI and EQ-5D-3L index scores over 12 months. In both biologic-naïve and biologic-experienced groups, multivariate analysis revealed a significant association between baseline HAQ-DI scores and endpoint HAQ-DI scores (β = 0.67, P < 0.001 and β = 0.76, P < 0.001, respectively), 12-month changes in HAQ-DI scores (both β = − 0.21, P < 0.001), and 12-month EQ-5D-3L index scores (β = − 0.57, P < 0.001 and β = − 0.29, P = 0.004, respectively). Baseline EQ-5D-3L index scores were significantly associated with 12-month changes in EQ-5D-3L index scores in both groups (β = − 0.73, P < 0.001 and β = − 0.40, P = 0.003, respectively). CONCLUSIONS: Patients with RA in persistent MDAS experience substantial ongoing physical disability, poor QoL, and pain. HAQ-DI is an important predictor of future disability and reduced QoL, supporting current national recommendations to measure HAQ-DI in routine care.