Renal arterial resistive index in Egyptian patients with lupus nephritis: Correlation with disease activity and biopsy parameters

Abstract

Lupus nephritis (LN) affects up to 60% of patients with systemic lupus erythematosus (SLE), either as the initial manifestation or during the disease course. Moreover, LN has a negative impact on survival of SLE patients. Accordingly, it is mandatory to identify specific and feasible markers able to guide clinicians towards the adequate therapeutic option in LN patients. The aim of this work was to evaluate the predictive value of renal resistance index (RRI), measured by Doppler Sonography in comparison with disease activity score, serologic and biopsy parameters in patients with LN. This study was carried out on forty three SLE patients, they were categorized into two groups: Group I included thirty three patients with LN and Group II included ten patients without LN and Group III included ten healthy subjects of matched age and sex as control group. All were subjected to history taking, clinical examination, assessment of disease activity by SLEDAI, laboratory investigations including FBG, blood urea, serum creatinine, serum albumin, CBC, ESR, CRP, complete urine analysis, 24 hour urine protein, eGFR, serum ANA, anti ds-DNA titre, C3, C4 and renal Doppler with measurement of RRI. Renal biopsy was done for those with LN. The mean value of RRI was statistically significantly higher in group I than that of group II and group III. Out of 33 cases of LN cases, 6 patients had RRI of 0.7 and above giving a percentage of 18.18%. LN patients with RRI higher than 0.7 had statistically significant higher age, mean serum creatinine and blood urea levels and a lower eGFR, higher chronicity index of renal biopsy. RRI is of clinical significance in predicting the chronicity index of renal biopsy which is a major determinant of renal outcome so it is useful as non invasive technique to evaluate chronicity in patients with LN, therefore justifying aggressive immune suppression but further follow-up studies are needed to evaluate its role in predicting response to treatment.

Keywords: Systemic lupus erythematosus, lupus nephritis, renal resistive index.

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