Tophi Detected by Ultrasound Linked to Kidney Impairment in Gout Patients

The presence of ultrasound feature of tophi is correlated with kidney dysfunction in patients with gout, regardless of clinical risk factors, according to a study in the Journal of Clinical Ultrasound.

To investigate the relationship between the specific ultrasonic manifestations of lower-limb joints and impaired kidney function in patients with gouty arthritis, investigators conducted a cross-sectional study, which included 408 patients diagnosed with gouty arthritis, who were categorized into 2 groups based on their renal function status: a normal kidney function group (n=240) and a renal impairment group (n=168).

All patients underwent comprehensive ultrasound examinations of their bilateral knee, ankle, and first metatarsophalangeal joints. The focus of these examinations was to identify specific ultrasound features, namely the double-contour sign (DC) and tophi. Multiple logistic regression analysis was employed to assess the potential association between kidney dysfunction and these ultrasound manifestations, with adjustments made for various clinical confounders.

Univariable conditional logistic regression analysis identified several significant risk factors associated with impaired kidney function (P<.05):

• Elevated levels of serum urate acid
• Disease duration
• Attack frequency
• Hyperlipidemia
• Hypertension
• Diabetes
• Coronary heart disease
• Presence of multiple tophi
• Presence of DC

However, after controlling for disease duration and other confounding factors, the relationship between kidney dysfunction and tophus remained significant. The multivariable adjusted odds ratio (OR) was 1.789 (95% CI, 1.005-3.185; P=.05). In contrast, the association between kidney dysfunction and DC was not statistically significant (OR, 1.098; 95% CI, 0.668-1.803; P=.71).

This study’s findings shed new light on the relationship between specific ultrasound manifestations and kidney function in patients with gouty arthritis. Notably, the presence of tophi, as detected by ultrasound, emerged as an independent risk factor for impaired kidney function. Even after adjusting for disease duration and other clinical risk factors, the association remained statistically significant. In contrast, the presence of the DC sign on ultrasound was not significantly associated with kidney dysfunction.