Renal hemodynamic alterations assessed by doppler ultrasonography in familial mediterranean fever patients without overt renal disease: a cross-sectional study

OBJECTIVE: Familial Mediterranean fever (FMF) is an autoinflammatory disease that may lead to renal parenchymal involvement and amyloidosis over time. Experimental and biopsy-based data from various renal diseases suggest that renal parenchymal injury may be accompanied by early alterations in renal hemodynamics. This study aimed to evaluate Doppler ultrasonography-derived renal hemodynamic parameters in adult FMF patients without overt renal involvement and to compare these findings with those of healthy controls. METHODS: This cross-sectional observational case-control study included 77 adult FMF patients without significant proteinuria (> 500 mg/g) and 75 age- and gender-matched healthy controls. Bilateral renal resistance index (RRI) and pulsation index (PI) measurements were performed in all participants using Doppler ultrasonography. In subgroup analysis, FMF patients were divided into two groups based on urinary protein excretion: those with normal or minimal proteinuria (< 150 mg/g) and those with low-grade proteinuria (150-500 mg/g). RESULTS: Both RRI and PI scores were significantly elevated in FMF patients than in controls (p < 0.05 for both). Subgroup analysis in FMF patients further revealed that RRI scores and PI scores were significantly higher in patients with low-grade proteinuria than in patients with normal or minimal proteinuria (p < 0.05 for both). CONCLUSIONS: Renal hemodynamic changes detected by Doppler ultrasonography can be identified in FMF patients, even when there is no apparent renal involvement. The greater increase in RRI and PI values was found in patients with low-grade proteinuria, indicating that changes in renal hemodynamics may be present at an early stage of the disease. These changes detected by Doppler ultrasonography may be used as an adjunctive tool for early evaluation of renal involvement in FMF.