Anti-RNAP, proteinuria predict development of scleroderma renal crisis

The development of scleroderma renal crisis (SRC), a severe life-threatening complication in patients with systemic sclerosis (SSc), is rare, but its highest risk is associated with the detection of anti-RNA polymerase antibodies (RNAP) and proteinuria, suggests a recent study.

A total of 2,873 patients with 10,425 visits had available data for analysis. The mean number of registry visits was 3.6±2.8, and the mean follow-up time was 3.6±3.8 years. Of the patients, only 70 (2.4 percent) developed SRC. More than half (n=40; 57.1 percent) were diagnosed with diffuse cutaneous SSC, 22 (31.4 percent) with limited cutaneous SSC and eight (11.4 percent) with SSc-overlap syndromes.

The highest risk of SRC was independently and significantly associated with positive anti-RNAP, a history of proteinuria prior to SRC onset, a history of hypertension and diminished diffusing capacity of the lungs for carbon monoxide. Of note, positive antitopoisomerase autoantibodies were not predictive of a higher probability for SRC.

In addition, patients with SRC received treatment with angiotensin-converting enzyme inhibitors (ACEi) and corticosteroids significantly more frequently without being independently associated with SRC.

In this study, the authors sought to determine the frequency of SRC and identified the risk factors for the prediction of the said condition. They used univariate and multivariate generalized estimating equations, based on regular follow-up data from the German Network for Systemic Scleroderma, to examine the relationship between clinical variables, SSc subsets, therapy (ie, ACEi, corticosteroids) and the occurrence of SRC.