Background/Purpose: Many studies have reported long-term outcomes including morbidity, mortality, and end stage kidney disease (ESKD) in patients with lupus nephritis (LN). We aimed to elucidate the risk factor of the progression to chronic kidney disease (CKD) in patients with lupus nephritis, and the development of comorbidity and its impact on the renal function.

Methods: We collected 116 patients with a diagnosis of LN who were hospitalized in our division from 2005 to 2013, and were followed up for at least 1 year or died within 1 year. We retrospectively examined the demographics, the clinical course, and the progression to CKD (defined as equal to or severer than G3bA1, G3aA2, or G2A3 by the classification for CKD). We performed COX hazard regression analysis to elucidate the risk factor of the progression to CKD and examined the impact of acute kidney injury (AKI) and acute decompensated heart failure (ADHF) on the renal function and the incidence of vascular event.

Results: The ratio of female to male was 8.7 : 1 and the median age of LN onset was 32 year-old. LN as one of the first symptoms was 54%, and 52% of LN showed proteinuria ≥ 3.5 g/day at least one time during the clinical course. Clinical symptoms and laboratory data included arthritis or arthralgia (41%), facial erythema (40%), serositis (20%), neurological symptoms (12%), hematological abnormality (22%), positive anti-double stranded DNA antibody (86%), and positive anti-phospholipid antibody (30%). In 98 renal biopsy-proven patients (86%), the pathological diagnoses (WHO classification) were class II (7%), IV (III) (45%), V (32%), and IV (III)+V (16%). Kaplan-Meier analysis showed survival, ESKD (introduction of dialysis or renal transplantation)-free, and CKD-free rate at 20 years were 0.761, 0.677, and 0.433, respectively (Figure 1). Multivariate COX hazard regression analysis revealed the hazard ratio of proteinuria ≥ 3.5 g/day for the progression to CKD was 2.01 (95% confidence interval, 1.06 to 3.81; p = 0.03). ADHF, AKI, and vascular events developed in 6, 9, and 12 patients, respectively. All patients with ADHF and 8 of 9 patients with AKI progressed to CKD eventually. There was a tendency that the cumulative incidence of vascular events in patients with CKD was higher than in those with non-CKD in the late phase (0.45 vs. 0.24, Figure 2). 

Conclusion: Nephrotic proteinuria was a risk factor of CKD, and ADHF and AKI may have a deteriorating impact on the subsequent renal function. In the late phase, vascular events should be cared for patients with LN who progressed to CKD.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/analysis-of-risk-factors-of-the-progression-to-chronic-kidney-disease-and-comorbidities-in-lupus-nephritis/