Renal Vascular Involvement Assessed by Intrarenal Resistive Index in Patients with Rheumatoid Arthritis: Associations with Structural Joint Damage and Cardiovascular Risk

Background/Objectives: Patients with rheumatoid arthritis (RA) have an increased risk of chronic kidney disease (CKD) and cardiovascular disease, largely driven by persistent systemic inflammation. This study aimed to assess the risk of CKD in RA patients and to evaluate its association with structural joint damage and cardiovascular risk (CVR). Methods: In this cross-sectional study, 70 patients fulfilling the 2010 ACR/EULAR criteria for RA were evaluated. Structural joint damage was assessed using the Sharp/van der Heijde score (SHS). Renal involvement was evaluated by estimated glomerular filtration rate (eGFR), urinary albumin-to-creatinine ratio (ACR), and intrarenal resistive index (RRI). CVR was assessed using the SCORE system, adjusted according to EULAR recommendations, and carotid ultrasonography was performed to assess intima–media thickness (IMT) and atherosclerotic plaques. Results: SHS was significantly correlated with renal and vascular parameters, showing positive associations with ACR, RRI, and carotid IMT, and a negative correlation with eGFR (all p < 0.0001). CVR correlated positively with SHS, ACR, RRI, and IMT. Patients with elevated RRI (≥0.70) had longer disease duration, more severe joint damage, impaired renal function, and higher CVR. Conclusions: In RA patients, cumulative articular damage is closely associated with renal dysfunction and increased CVR, highlighting the central role of sustained inflammation in multiorgan involvement.