Systemic lupus erythematosus (SLE) patients with rheumatoid arthritis have joint surgery rates almost four times higher than those with non-RA SLE, Western Australia data shows.
The observational study of the Western Australia Rheumatic Disease Epidemiology Registry (WARDER), led by Dr Johannes Nossent, concluded that not only are SLE patients at a significantly higher risk of requiring joint procedures than non-SLE patients, but that additional RA significantly increased the risk further.
Commonly referred to as rhupus, joint abnormalities similar to RA develop in some SLE patients despite arthritis in SLE generally being considered mild and non-erosive. Around one third (35%) of rhupus patients in this study required surgical joint procedures, compared to 10.2% of non-RA SLE patients.
Previous studies have reported higher rates of hip arthroplasty in patients with SLE than those without inflammatory rheumatic disease, but this is the first analysis to show that arthroplasty, arthrodesis and synovectomy were all significantly higher in patients with SLE (rhupus and non-RA) than age and sex-matched controls (11.6% v 1.3%).
Moreover, requiring more than one joint procedure was also more common in those with SLE than those in the control group (12.9% v 3.5%).
Data from over 1800 patients aged 15-75 with SLE were compared to a propensity-matched control group of almost 13,000 people over a 30-year period (1985-2014). Rhupus patients made up 6.5% of the SLE group and had higher incidence of wrist and shoulder arthroplasties, but fewer hip arthroplasties than those with other SLE.
Interestingly, osteoarthritis incidence over this time increased among the SLE group, while osteonecrosis rates decreased.
Rhupus is poorly understood and no guidelines for arthritis management in SLE or uniform diagnostic criteria currently exist. In this study, rhupus was classified as an SLE diagnosis and at least two additional diagnostic codes for RA.
The full extent of the burden of rhupus remains unknown but researchers suggest arthritis intervention in these patients may be needed.
“The results support a more aggressive approach towards arthritis management, such as now commonplace in rheumatoid arthritis. This could help reduce joint damage and surgery in patients with lupus”, the authors suggested.