Objectives 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.
Methods 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).
Results 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).
Conclusions 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.
- psoriatic arthritis
- rheumatoid arthritis
- outcomes research
- patient perspective
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Contributors BM, TU, JS, DvdH, HBH, EKK, JHL, GH and TKK were responsible for study design. TU, AW, GB, ER, FK and TKK were responsible for data acquisition. BM analysed the data and wrote the manuscript. All authors critically revised the manuscript and approved the final version.
Funding The study was funded through clinical research fellowships from Diakonhjemmet Hospital (originating from South-Eastern Health Authority) and from The Hospital of Southern Norway Trust and through a grant from Grethe Harbitz’ Legacy. Data collection in NOR-DMARD was partly funded through unrestricted grants from Abbvie, BMS, MSD, Pfizer (Wyeth), Roche and UCB.
Competing interests None declared.
Patient consent Not required.
Ethics approval The study was approved by the National Data Inspectorate and by the Regional Committee for Medical and Health Research Ethics in Eastern Norway.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All relevant data are within the text.
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