The Presence of Monosodium Urate Deposits in the Joints of Patients with Asymptomatic Hyperuricemia is Associated with a Higher Cardiovascular Risk, But Not with More Advanced Kidney Damage

Abstract Aim To evaluate the association between asymptomatic hyperuricemia, renal damage and cardiovascular events and to investigate whether the presence of monosodium urate (MSU) deposits in the joints is related to more advanced renal changes and increased cardiovascular risk. Methods This was a study on 73 consecutive patients divided into 34 patients with osteoarthritis, 25 subjects with asymptomatic hyperuricemia and no ultrasound (US) evidence of MSU crystals in the joints and 14 individuals with asymptomatic hyperuricemia and MSU deposits in the joints. Patients underwent bilateral US examination of the joints of the hands, elbows, knees, ankles, feet and the kidneys. Routine abdominal ultrasound with evaluation of kidney and parenchymal size and echogenicity and renal vascular indices was performed. The presence of cardiovascular complications in the past was evaluated from the patients‘ history. The study protocol was a continuation of another project from 2013 (14-D2013, approved by the ethics committee of the Medical University – Sofia). Informed consent was obtained from all patients prior to the inclusion in the study. The study was conducted in accordance with the Declaration of Helsinki. Results The highest proportion of patients with cardiovascular events was detected in the group of asymptomatic hyperuricemia with MSU deposits in the joints. The patients with osteoarthritis had the lowest prevalence of eGFR < 90 ml/min. Renal parenchymal echogenicity and the prevalence of nephrolithiasis were compatible for all groups. Patients with hyperuricemia and MSU deposits in the joints had higher BMI (p = 0.018) and smaller kidney size (p = 0.015) compared to those with osteoarthritis. The comparison of hyperuricemia without MSU deposits in the joints to osteoarthritis group demonstrated a significant difference only in the age (p = 0.001). Finally, the comparison of the two groups with hyperuricemia showed that subjects with MSU deposits in the joints had higher BMI (p = 0.041) with no difference in the age, kidney size, RRI, eGFR and thickness of renal parenchyma. Conclusions Hyperuricemia, independent of the presence of articular crystals, is associated with compatible kidney damage. Cardiovascular risk is higher when MSU crystals are detected in the joints using US.