Background/Purpose:

Scleroderma renal crisis (SRC) usually presenting with accelerated hypertension and acute kidney injury (AKI) is one of the most severe complications of Systemic Sclerosis (SSc). The presence of RNA-polymerase III auto-antibodies (ARA) is recognized as a strong risk factor for SRC but studies have not explored long-term outcomes in ARA positive cases compared to ARA negative cases.

Methods:

Of more than 2000 SSc patients attending our institution between 1990-2013, 150 patients had a confirmed SRC. 80% patients had diffuse cutaneous SSc (dcSSc) and 20% patients had limited cutaneous SSc (dcSSc). ARA was measured by commercial ELISA or radio-immuno-precipitation. Patients were divided into two groups: ARA positive or ARA negative. Demographic and clinical parameters were compared between groups using Student’s t-test or Chi-squared analyses where appropriate.

Results:

61/150 (41%) patients were ARA positive and significantly more likely to have dcSSc (88.3% vs 73.8%, p=0.032) than lcSSc compared to ARA negative patients. There was no significant difference in age of onset of SRC (51.2 vs 51.9 years) or the number of females (73% vs 79%) between the two groups. 50.8% of ARA positive patients required dialysis compared to 29.2% of ARA negative patients (p=0.07). The mean time to recovery of renal function was significantly longer in ARA positive patients (14.25 vs 8.27 months, p=0.032). Significantly more ARA positive patients were able to discontinue dialysis compared to ARA negative patients (53.3% vs 25.5%, p=0.01). ARA positive patients had a significantly better survival outcome (figure 1).

Conclusion:

In SRC, although more ARA positive patients required dialysis they also had significantly greater capacity for long-term recovery and survival compared to ARA negative patients.

Figure 1: Kaplan Meier survival estimate showing the effect of ARA positive auto-antibodies in patients with SRC