Predictors of Renal Flare in Lupus Population Identified – Renal and Urology News

Investigators have identified characteristics that signal impending renal flares among patients with systemic lupus erythematosus (SLE).

In a post-hoc analysis of 4 phase 3 clinical trials of belimumab involving 3225 patients with SLE, 192 patients experienced at least 1 renal flare, with the first occurring after a median 197 days.

In the overall cohort, current/former renal involvement was significantly associated with a 15.4-fold increased risk of renal flare. Low C3 levels and high proteinuria at baseline also were significantly associated with a 2.9- and 1.6-fold increased risk, respectively, Ioannis Parodis, MD, PhD, of Karolinska University Hospital in Stockholm, Sweden, and colleagues reported in Rheumatology. The presence of anti-double stranded DNA also was associated with renal flares, but the association attenuated after adjustments in multivariable models.

The investigators looked for additional prognosticators among the groups treated with belimumab vs placebo on top of standard therapy. Anti-Sm was significantly associated with a 3.7-fold increased risk for renal flares in the placebo group only, which coincides with results from a previous study. Anti-ribosomal P positivity was significantly associated with a 2.8-fold increased risk of renal flares in the belimumab group only.

“Even though further investigation is needed regarding the presence of anti-ribosomal P protein antibodies in patients with SLE in relation to kidney involvement, our findings point towards predictive properties for these autoantibodies, which may prove useful in monitoring renal flare development, especially in patients starting belimumab therapy.”

Low serum albumin levels were significantly associated with a 10% lower risk of renal flare.

Patients with current or former renal involvement had a more than 9-fold increased risk for a new renal flare. Flare was more likely among younger and Asian patients. Renal flares were defined as a proteinuria rise to more than 1 g/day from a baseline value of less than 0.2 g/day; a rise to more than 2 g/day if the baseline value was 0.2-1.0 g/day; or a doubling if the baseline value was more than 1 g/day. Other criteria included a serum creatinine rise of 20% or more or 0.3 mg/dL, along with proteinuria, hematuria, or red blood cell casts. The third definition was new hematuria of glomerular origin, along with proteinuria or red blood cell casts.

Dr Parodis’ team noted that C3 was more reflective of renal activity than C4. In a separate study published in Kidney International Reports, Lubka T. Roumenina, PhD, of Cordeliers Research Center, INSERM UMRS in Paris, France, and colleagues also found that autoantibodies to C3 were more strongly associated with disease activity and future flares in a cohort of 85 patients with established lupus nephritis. C3 antibodies were associated with hypocomplementemia, anti-dsDNA, class 4 lupus nephritis, and active disease according to British Isles Lupus Assessment Group (BILAG) renal score.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.