Double Contour Sign In Early Detection Of Gout Among Asymptomatic Hyperuricemic Filipino Patients: A Single Center Tertiary Hospital Observational Study

Objective. Double contour sign (DCS) is considered part of the new gout classification. This study aims to determine the agreement of blinded musculoskeletal sonologists in identifying the double contour sign among asymptomatic hyperuricemic patients. Methods. Participants with asymptomatic hyperuricemia (n=65) underwent a gray-scale ultrasound assessment of both of their 1st metatarsophalangeal joints (MTPJs) done on 3 positions (dorsal, medial, plantar) in longitudinal view. The static images were read by 2 independent blinded sonologists for presence of double contour sign. Results. Among the 130 1st MTPJs, the sonologists were able to positively identify DCS on 48R and 52L, negative in 10R and 10L, with discordant readings in 7R, 3L. The overall kappa agreement was statistically significant at 0.674 (substantial agreement) and 0.842 (almost perfect agreement) on the right and left respectively, (both p<0.001). Conclusion and Recommendation. There is a high proportion of positive double contour sign seen among persistently asymptomatic hyperuricemic patients. It might be prudent to perform musculoskeletal ultrasound early on to detect monosodium urate crystal deposits in similar patients. A close follow up to monitor clinical gouty arthritis may be necessary or consider utility of urate lowering drugs in crystal dissolution in prospective studies.