Objectives: We undertook this study to evaluate the responsiveness of Doppler ultrasound (US) to urate lowering therapy (ULT) in gout patients.
Methods: Twenty-four consecutive patients were prospectively included from an outpatient clinic. The patients underwent clinical, and US assessment at baseline and after 6, 12 and 24 months of ULT. The US assessment was made by another rheumatologist blinded to the clinical data. Standardised examinations were performed in four joints (both first metatarso-phalangeals and knees) and the patellar tendons. The Doppler signals were scored. The mean and standard deviation were calculated for each parameter. The comparison between the quantitative values was performed by Student's t-test. Sensitivity to change in the US examinations was assessed by estimating the smallest detectable difference (SDD) in the total Doppler score.
Results: A Doppler signal was detected in 95.8% of the patients at the baseline. A significant parallel improvement in the serum urate level, clinical parameters and in Doppler scores was found at the follow-up assessment. 62% of the patients had achieved a uric concentration level below 6 mg/dl at one year. At two years, persistence of a Doppler signal was found in 72.7% of the patients. The SDD in the Doppler score at 2 years was 1.92, lower than the difference achieved.
Conclusions: The Doppler US findings show significant improvement and responsiveness after ULT in gout patients. The Doppler signal persistence after two years of treatment is marked. This finding introduces a reflection on the accuracy of the current outcome measures and treatments.