RA patients are often not in remission due to patient global assessment of disease activity (PtGA) included in disease activity indices. The aim was to assess the lag of patient-reported outcomes (PROs) after remission measured by clinical disease activity index (CDAI) or swollen joint count (SJC28).
RA patients enrolled in the Ontario Best Practices Research Initiative registry not in low disease state at baseline with at ≥6 months of follow-up, were included. Low disease state was defined as CDAI ≤ 10, SJC28 ≤ 2, PtGA ≤ 2cm, pain score ≤ 2cm, or fatigue ≤ 2cm. Remission included CDAI ≤ 2.8, SJC28 ≤ 1, PtGA ≤ 1cm, pain score ≤ 1cm, or fatigue ≤ 1cm. Time to first low disease state/remission based on each definition was calculated overall and stratified by early vs established RA.
A total of 986 patients were included (age 57.4 (12.9), disease duration 8.3 (9.9) years, 80% women). The median (95% CI) time in months to CDAI ≤ 10 was 12.4 (11.4, 13.6), SJC28 ≤ 2 was 9 (8.2, 10), PtGA ≤ 2cm was 18.9 (16.1, 22), pain ≤ 2cm was 24.5 (19.4, 30.5), and fatigue ≤ 2cm was 30.4 (24.8, 31.7). For remission, the median (95% CI) time in months to CDAI ≤ 2.8 was 46.5 (42, 54.1), SJC28 ≤ 1 was 12.5 (11.4, 13.4), PtGA ≤ 1cm was 39.6 (34.6, 44.8), pain ≤ 1cm was 54.7 (43.6, 57.5) and fatigue ≤ 1cm was 42.6 (36.8, 48). Time to achieving low disease state and remission was generally significantly shorter in early RA compared with established RA with the exception of fatigue.
Time to achieving low disease state or remission based on PROs was considerably longer compared with swollen joint count. Treating to a composite target in RA could lead to inappropriate changes in DMARDs.