Ultrasound Renal Stress Test Assessment in Moderate-to-Severe Psoriasis: A Pilot Study.

BACKGROUND: Psoriasis is increasingly recognized as a systemic inflammatory disease and has been associated with chronic kidney disease. Whether psoriasis is also linked to subclinical impairment in renal microcirculation remains unclear. OBJECTIVE: To assess renal functional reserve (RFR) in patients with moderate-to-severe psoriasis using the renal stress test (RST). METHODS: Fifty-one consecutive adults with psoriasis and 35 age- and sex-matched controls underwent RST. Renal resistive index (RRI) was measured by Doppler ultrasound in an interlobular renal artery at baseline and after abdominal compression with a fluid-filled bag corresponding to 10% of body weight. Intrarenal resistive index variation (IRRIV) was calculated as the percentage difference between baseline and stress values. RESULTS: Patients with psoriasis showed a lower IRRIV than controls (median 13.8% [10.7-18.6] vs 23.1% [17.8-25.0]; p<0.001). IRRIV differed significantly across controls and Psoriasis Area and Severity Index (PASI) severity strata (p<0.001), but post hoc pairwise comparisons showed that this difference was driven by the comparison between controls and psoriasis patients, with no significant difference between severity strata. In multivariable analysis, psoriasis remained independently associated with lower IRRIV. LIMITATIONS: This was a single-center pilot study with a limited sample size. CONCLUSION: Moderate-to-severe psoriasis was associated with impaired renal functional reserve, suggesting subclinical renal microcirculatory dysfunction. Larger studies are needed to confirm these findings and define their clinical relevance.