The aim of a study was to investigate the prevalence of monosodium urate ( MSU ) crystal deposits, indicative for gout, in a population of rheumatoid arthritis ( RA ) patients with concomitant hyperuricemia and to analyze the clinical and disease-specific characteristics of patients with rheumatoid arthritis who exhibit MSU crystal deposits.
Overall, 100 consecutive patients with the diagnosis of rheumatoid arthritis and a serum urate level above 6mg/dl underwent dual energy computed tomography ( DECT ) of both feet and hands to search for MSU crystals in a prospective study between October 2011 and July 2013.
Hyperuricemic patients with rheumatoid arthritis were mostly male ( 55% ), over 60 years of age ( 63 ± 11 years ), had established disease ( 8.7 ± 10.5 years ) and a mean disease activity score 28 ( DAS 28 ) of 3.2.
In total, 20 out of 100 patients displayed MSU crystal deposits in DECT.
Interestingly, the majority ( 70% ) of the patients with rheumatoid arthritis, positive for MSU crystal deposits, were seronegative RA patients. Hence, every third seronegative RA patient had MSU crystal deposits.
According to logistic regression model analysis, seronegative status correlated positively with presence of urate deposits ( p = 0.019 ).
In conclusion, these data have shown that a considerable number of patients with rheumatoid arthritis display periarticular MSU crystal deposits.
Seronegative patients were shown to be predominantly affected with every third patient being positive for urate deposits. ( Xagena )
Petsch C et al, Semin Arthritis Rheum 2015; Epub ahead of print