(HealthDay News) — Proteinuria levels at 12 months are the best predictor of long-term renal outcome in patients with lupus nephritis, according to a study published in the May issue of Arthritis & Rheumatology.

Maria Dall’Era, MD, from the University of California in San Francisco, and colleagues analyzed data from the Euro-Lupus Nephritis Trial to evaluate the performance of proteinuria, serum creatinine (Cr), and urinary red blood cells (RBCs) as predictors of good long-term renal outcome (defined as a serum Cr value ≤1.0mg/dL) in patients with lupus nephritis. Seventy-six patients were followed for a minimum of seven years.

The researchers found that a proteinuria value of <0.8gm/day at 12 months after randomization was the single best predictor of good long-term renal function (sensitivity of 81% and specificity of 78%). The performance of the outcome measure was not improved with the addition of serum Cr to proteinuria. Sensitivity dropped to 47% with the addition of urinary RBCs.

The authors suggest “that urinary RBCs should not be included as a component of clinical trial response criteria in lupus nephritis.”

One author disclosed financial ties to the pharmaceutical industry.

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