Background and objectives: The objective of this study was to determine the clinical significance of renal vascular lesions in lupus nephritis.
Design, setting, participants, & measurements: Renal vascular lesions defined as thrombotic microangiopathy, lupus vasculopathy, uncomplicated vascular immune deposits, and arterial sclerosis were evaluated in relation to renal and vascular morbidity and overall mortality.
Results: Biopsies from 161 patients revealed thrombotic microangiopathy (13), lupus vasculopathy (5), and arterial sclerosis (93). No renal vascular lesions were found in 24.8% of patients. At the time of biopsy, arterial sclerosis or lupus vasculopathy patients were older (arterial sclerosis=37.9±13.0 and lupus vasculopathy=44.4±8.9 versus controls=33.1±8.9 years, P<0.05), and the mean arterial pressure was higher in all groups compared with controls. Nephritis subtype, activity indices, and proteinuria were similar between groups, estimated GFR was lower in arterial sclerosis (70.5±33.3 versus 84.5±26.6 ml/min per 1.73 m(2), P=0.03), and chronicity index (thrombotic microangiopathy=3.5, lupus vasculopathy=4.5, and arterial sclerosis=2.5) was higher in all renal vascular lesions subgroups versus controls (1.0, P<0.05). In 133 patients with similar follow-up, the association between renal vascular lesions and vascular events was significant (Fisher exact test, P=0.002) and remained so after multivariate analysis (exact conditional scores test, P=0.04), where the difference between arterial sclerosis and uncomplicated vascular immune deposits was most noticeable (odds ratio [95% confidence interval]=8.35[0.98, 83.12], P=0.05). The associations between renal vascular lesions, renal outcomes, and death were not significant, likely because of insufficient power.
Conclusions: Renal vascular lesions are common in SLE patients with nephritis and may be associated with arterial vascular events.