To compare (1) Short Form-36 (SF-36) Physical Component Summary (PCS) and Mental Component Summary (MCS), scale scores and Short Form-6 dimensions (SF-6D) between patients with rheumatoid arthritis (RA) and patients with psoriatic arthritis (PsA) and Norwegian general population controls and (2) improvements in these measures between patients with RA and PsA.
Analyses of covariance were performed to compare SF-36 measures between first-time enrolled patients with RA (n=3898) and PsA (n=1515) from the prospective observational multicentre NORwegian-Disease Modifying Anti-Rheumatic Drug study (6 months follow-up) and general population controls (n=2323).
In age and gender-adjusted analyses, patients with PsA compared with patients with RA had similar PCS, MCS and SF-6D (p≥0.14), worse vitality and general health, but better physical functioning at 0/6 months (p≤0.03). With additional 28-joint disease activity scores adjustment as a proxy for joint inflammation, PCS, most scale scores and SF-6D were worse in patients with PsA than patients with RA at 0/3/6 months (p≤0.01). PCS was more impaired than MCS both in RA and PsA compared with general population controls (p≤0.001). Mean 3-month and 6-month improvements after disease-modifying anti-rheumatic drug treatment were larger in patients with RA than patients with PsA for bodily pain, vitality and mental health (p≤0.02).
Health-related quality of life was overall similar in patients with RA and patients with PsA-with a tendency to worse scores in PsA-and worse compared with Norwegian general population controls.