Article Text
Abstract
Aim To investigate the relationship between health-related quality of life (HRQoL) and remission as a target in a treat-to-target approach of systemic lupus erythematosus (SLE) in a longitudinal observational cohort study.
Methods HRQoL was assessed with the physical and mental component score (PCS and MCS, respectively) of the SF-36 questionnaire and adjusted for the Dutch general population (mean 50±10). DORIS remission categories (no remission/remission on therapy/remission off therapy) were applied 1. Determinants of PCS and MCS were identified with simple linear regression analyses. Association between remission and HRQoL was assessed with General Equation Estimation (GEE) models.
Results Data from 154 patients with 2 years of follow-up were analysed. Patients were mostly female (89%) and Caucasian (69.5%). Remission off therapy was present in 27.3% of patients, 18.1% were in remission on therapy, and 54.5% were not in remission. Mean PCS at baseline was 38.1 (±11.1) and mean MCS was 46.3 (±10.6). Patients in remission (as defined by remission on or off therapy) had higher SF-36 scores in all subdomains compared to patients not in remission. PCS was positively associated with employment and remission, while negatively associated with ESR, patient global assessment, SLE-damage- index, prednisone use, immunosuppressant use, and body mass index. MCS was positively associated with Caucasian ethnicity and negatively associated with patient global assessment.
PCS at the last visit was higher in patients in remission during 2 years (n=44) compared to patients (n=44) who were never in remission during 2 years of observation (mean 45.9 vs mean 36.8, p<0.001, respectively).
In GEE analysis, a gradual and statistically significant increase of PCS was observed from patients not in remission (mean PCS 36.0) to remission on therapy (41.8) to remission off therapy (44.8). No significant difference in MCS was found between remission states.
Conclusion We show a longitudinal relationship between PCS – but not MCS – and remission, which supports the validity of DORIS remission criteria as a treatment goal in SLE. A lack of association between MCS and remission might be explained by near-normal MCS scores in our cohort. Secondly, non-disease related factors might more importantly influence MCS.