Remission vs low disease activity: function, quality of life and structural outcomes in the Early Rheumatoid Arthritis Study and Network

Abstract

Objectives: To examine associations between function, quality of life and structural outcomes in patients achieving remission vs low disease activity in early RA.

Methods: Demographic, clinical and radiographic variables were collected at baseline and then annually from the Early Rheumatoid Arthritis Study (ERAS) and Early Rheumatoid Arthritis Network (ERAN) inception cohorts in routine care from 1986 to 2012. Disease activity was categorized: mean DAS28 score between years 1 and 5: remission [mean remission DAS (mRDAS) <2.6] or low [mean low DAS (mLDAS) 2.6-3.2]; sustained low/remission DAS28 (sLDAS/sRDAS) at years 1 and 2; and sustained Boolean remission (sBR) at years 1 and 2. Changes in HAQ and Short Form 36 Health Survey Questionnaire [SF-36; physical (PCS) and mental (MCS) component score]) and total Sharp van der Heijde (SvdH) scores for each disease activity category were modelled using multi-level models. Covariates included year of onset, age, gender and DMARD use at first visit.

Results: Of 2701 patients, 562 (21%) were categorized mRDAS, 330 (12%) mLDAS, 279 (10%) sRDAS, 203 (7.5%) sLDAS and 93 (3%) sBR. Patients categorized as mRDAS had increasingly divergent improved HAQ, SF-36 PCS, MCS and total SvdH scores compared with mLDAS (P-values 0.001 to <0.0001, all time points). Patients categorized as sRDAS had better HAQ, SF-36 PCS and MCS scores (P-values 0.05 to <0.0001, all time points) and SvdH scores (P = 0.05, years 3-5) over sLDAS. sBR was associated with better HAQ, and SF-36 PCS and MCS scores over sLDAS (P-values 0.002 to <0.0001, all time points).

Conclusion: These findings from routine care support ACR/EULAR guidelines that remission is a preferable goal over low disease activity in early RA.

Keywords: damage; function; life quality; low disease activity; remission; rheumatoid arthritis.

Fig. 1

Box plot of DAS28 scores over years 1–5 for the mean remission DAS group, and the mean low DAS group The white line in the middle of the boxes represents the median values, whilst the outer part of the boxes indicates the 25th and 75th percentiles. The whiskers extending from the boxes indicate the upper and lower adjacent values (within 1.5× IQR of the median), whilst the circles outside the whiskers represent outside values. The black dashed lines across the plots indicate the threshold for remission DAS (2.6) and low DAS (3.2) categorization. IQR: interquartile range.

Fig. 2

HAQ, SF-36 MCS, SF-36 PCS and total SvdH estimated mean scores in entire ERAS/ERAN cohort and patients categorized as mLDAS and mRDAS Patients categorized as mean LDAS or mean RDAS based on mean score from years 1, 2 3, 4 and 5. Analysis controlled for year of recruitment, age of RA onset, gender and baseline treatment. SF-36: Short Form 36 Health Survey Questionnaire; MCS: mental component score; PCS: physical component score; SvdH: Sharp van der Heijde; ERAS/ERAN: Early Rheumatoid Arthritis Study/Early Rheumatoid Arthritis Network; mLDAS: mean low DAS; mRDAS: mean remission DAS.

Fig. 3

HAQ, SF-36 MCS, SF-36 PCS and total SvdH estimated mean scores in entire ERAS/ERAN cohort and patients categorized as sLDAS and sRDAS Patients categorized as sustained LDAS or sustained RDAS based on outcomes at both year 1 and 2. Analysis controlled for year of recruitment, age of RA onset, gender and baseline treatment. SF-36: Short Form 36 Health Survey Questionnaire; MCS: mental component score; PCS: physical component score; SvdH: Sharp van der Heijde; ERAS/ERAN: Early Rheumatoid Arthritis Study/Early Rheumatoid Arthritis Network; sLDAS: sustained low DAS; sRDAS: sustained remission DAS.