SLE Renal Outcomes for Mixed LN vs Pure Proliferative LN

This article originally appeared here.
No association was found between mixed or pure histopathologic features of LN at presentation and rates of complete or partial remission
No association was found between mixed or pure histopathologic features of LN at presentation and rates of complete or partial remission

Researchers from Fort Worth, Texas, Ann Arbor, Michigan, and Atlanta have investigated the association between mixed proliferative lupus nephritis (MPLN), pure proliferative lupus nephritis (PPLN), and short-term renal outcomes. 

They found that there was no association between mixed or pure histopathologic features of lupus nephritis (LN) at presentation and future rates of complete or partial remission. They did find, however, that higher baseline estimated glomerular filtration rate (eGFR) was associated with a lower probability of complete remission among patients with LN.1 

“When compared to pure membranous LN, mixed membranous LN [has been] found to have worse long-term outcomes, specifically in terms of patient survival and progression of renal disease,” wrote Titilayo O. Ilori, MD, from the Emory University School of Medicine in Atlanta and colleagues. “However, few studies have compared outcomes in individuals with MPLN and PPLN, and even fewer studies have [examined] the comparative outcomes of MPLN and PPLN under the new ISN/RPS classification.”

The researchers aimed to compare renal outcomes in patients with MPLN vs patients with PPLN, and to identify predictors of clinical outcomes among those with MPLN and PPLN. They retrospectively reviewed 278 patients with LN (≥18 years old) identified from an Emory University Hospital registry of native renal biopsies performed between January 2000 and December 2011. The final analytic sample consisted of 156 participants with a diagnosis of PPLN (n=60) and MPLN (n=96).

High Yield Data Summary

  • No association was found between mixed or pure histopathologic features of LN at presentation and rates of complete or partial remission

The researchers found no association between proliferative LN and time to end stage renal disease or complete remission, implying that there is no association between the histological category of proliferative LN and ESRD or complete remission. 

Baseline eGFR was found to be associated with remission among all patients. Each 1-ml/min/1.73 m2 increase in eGFR, was associated with 10% lower risk (hazard ratio [HR] = 0.90,  95% CI = 0.84, 0.98) 

“Our results differ from other studies that have shown that the prognosis in individuals with MPLN is worse than that of PPLN,” the authors wrote. 

The authors noted that these differences may have been due to a number of reasons, including the race of participants, differences in treatment (predinisone and cyclophosphamide with or without plasmapharesis in a study by Najafi et al, compared with a variety of treatment protocols including mycophenolate mofetil in the current study2), and follow up time (mean follow up of 10 years +/- 5.42 years in the Najafi et al study, compared with mean follow up of 1.02 years for remission and 1.52 years for end stage renal disease in the current study.)

Summary and Clinical Applicability

Researchers found no association between mixed or pure histopathologic features of LN at presentation and rates of complete or partial remission, but did find that higher baseline eGFR was associated with a lower probability of complete remission among patients with LN.

"This study warrants follow-up investigations to elicit similarities and differences between the classes of proliferative LN. This will ultimately inform treatment strategies unique to addressing the underlying mechanistic disease process," the authors concluded.

Limitations and Disclosures

The study was inherently limited by its retrospective nature and a relatively small sample. Different definitions of complete remission may have led to misclassification and the inability to detect a significant difference between the 2 groups. 

“By combining the 2 proliferative groups of LN together, we may have obscured vital morphological differences that correlate with clinical differences and prognostic determination,” the authors wrote.

The researchers also did not record outcomes such as mortality, so these cases were not censored if they occurred. Other individuals may also have been lost to follow-up, which may not have been captured.

The study is also limited by a short-follow up period for outcomes remission and end stage renal disease. The median follow up was 1.02 years for remission and 1.52 years for end stage renal disease, compared with other studies that had a median follow up of 10 years.

Sources

1. Ilori TO, Enofe N, Oommen A, et al. Comparison of outcomes between individuals with pure and mixed lupus nephritis: A retrospective study. PLoS ONE. 2016;11(6): e0157485. doi:10.1371/journal.pone.0157485

2. Najafi CC, Korbet SM, Lewis EJ, Schwartz MM, Reichlin M, Evans J, et al. Significance of histologic patterns of glomerular injury upon long-term prognosis in severe lupus glomerulonephritis. Kidney International. 2001;59(6):2156–63. doi: 10.1046/j.1523-1755.2001.0590062156.x pmid:WOS:000168619300015.

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