Background Ultrasound (US) evidence of double contour (DC) sign has been incorporated to new ACR/ EULAR gout classification criteria. Other specific US symptoms like tophus (T) and unspecific features like synovial hypertrophy (SH), synovial effusion (SE) are still under investigation. Which joints should be investigated – only symptomatic or more - still a matter of debate . The US studies with rheumatoid arthritis showed that US adds information to clinical findings . The concordance between clinical symptoms and ultrasound in gout still needs to be investigated.
Objectives to evaluate concordance between clinical examination, patient reported gout symptoms and ultrasound findings in gout patients.
Methods observational, prospective, controlled single centre study has been performed. 50 crystal proven gout patients with different disease duration, activity and treatment and 36 healthy controlls has been included. 36 joints were systematically investigated by experienced rheumatologist, blinded to patients clinical data and complaints. The concordance between clinical signs, such as tender joints and swollen joints defined by other rheumatologist, joints with previous gout flares, reported by the patient and presence of ultrasonographic SE, SH, DC and T was assessed by computing the kappa coefficient.
Results the concordance between patient reported gout flare (PRGF) and SH, SE was poor with kappa 0,125 (95% CI 0,070–0,179) and 0,136 (95%CI 0,082–0,190) accordingly. The concordance between (PRGF) and T, DC and combination of T plus DC was fair – kappa 0,325; 0,275 and 0,376 accordingly. There was negative kappa (-0,053) between reported joint flare in I MTF and DC sign, poor concordance between knee, ankle PRGF and DC sign. Negative kappa (-0,005) between PRGF and T in wrist joints. The concordance between US T and DC and patient reported flare stayed fair in untreated (33) group. The strongest concordance between PRGF and T, considered as moderate (kappa 0,420; 95% CI 0,296- 0,544) was found in early gout group (16 patients), with fair agreement according DC sign in this subgroup. Poor agreemant was found between SE, SH, T and DK and objectively found tender and swollen joints, ultrasound was found to be much more sensitive - SH in 92% (195/211) cases, T in 93% (211/228) of cases and DC in 92% (268/290) of cases was found in non swollen joints. The overall specificity of DC, T and SH according controls was 86% (p<0,0001), 81% (p<0,0001) and 64% (p<0,0001).
Conclusions The concordance between patient reported gout flare in the joint and US tophus or double contour sign was poor to fair in total gout group and moderate in early gout according tophus. We found no agreement according clinics and tophus sign in wrist and double contour sign in I MTF. Ultrasound added information to clinical examination with good specificity for tophus and double contour sign.
Grassi, W., Okano, T., & Filippucci, E. (2015). Use of ultrasound for diagnosis and monitoring of outcomes in crystal arthropathies. Current Opinion in Rheumatology, 27(2).
Garrigues, F., Jousse-Joulin, S., Bouttier, R., Nonent, M., Bressollette, L., & Saraux, A. (2013). Concordance between clinical and ultrasound findings in rheumatoid arthritis. Joint, Bone, Spine: Revue Du Rhumatisme, 80(6), 597–603. doi:10.1016/j.jbspin.2013.03.011
Disclosure of Interest None declared