To examine the frequency of gouty arthritis in patients with systemic lupus erythematosus (SLE) and elucidate the clinical factors that predispose to this occurrence.
A chart review of in-patients (1989-2001) and out-patients (1999-2001) with ICD9 billing codes for gouty arthritis/tophaceous gout and SLE was performed. Twenty-six patients were identified. Patients meeting American College of Rheumatism criteria for SLE and crystal-proven gout or a self-limited inflammatory arthritis felt to be crystal-induced (i.e. definite gout) were included.
Ten patients were identified. Their mean age was 46.5 yr; 80% were African-American and 70% were women. Nine of the ten had lupus nephritis and four had undergone renal transplantation. An acute worsening of renal function unrelated to lupus activity preceded almost all gout flares. Lupus activity at the time of the first gout attack as measured by the Systemic Lupus Activity Measure (SLAM) was low. Eight patients were on prednisone (mean dose 8 mg/day) for their SLE at the time the attack of gout occurred.
Gouty arthritis is uncommon in SLE; it occurs primarily in patients with long-standing SLE and nephritis. Worsening renal function usually preceded gout attacks, but SLE disease activity was minimal. Crystal-induced arthritis should be included in the differential diagnosis of a lupus patient presenting with acute inflammatory arthritis because the long-term treatment of the two conditions differs substantially.