Decreasing prevalence and cumulative incidence of scleroderma renal crisis over time: associated factors identified...

To determine the prevalence and incidence of scleroderma renal crisis (SRC) in patients with SSc over two time periods and to identify factors influencing potential epidemiological changes.

A total of 1939 SSc patients were categorized based on their diagnostic date. The 'historical cohort' (HC) included patients diagnosed before 31 December 2002, while the 'contemporary cohort' (CC) included those diagnosed afterwards. Epidemiological differences in SRC between both cohorts were investigated in the overall SSc series, and according to cutaneous subsets and antibody profile. If differences were present, the factors involved were assessed.

Forty-four patients developed SRC (prevalence rate: 2.3%), first-year incidence: 2.09 events per 100 person-years. Patients with diffuse cutaneous subset (dcSSc) (8.1%), anti-RNA polymerase III positive antibodies (12.0%) or anti-topo I positive antibodies (4.3%) had a higher prevalence of SRC than those with limited cutaneous subset (lcSSc) (0.9%) or anti-centromere-positive antibodies (0.7%). SRC prevalence decreased over time (HC vs CC) in the overall SSc series (3.7% vs 1.3%; P = 0.001), definite-SSc cohort (3.9% vs 1.4%; P = 0.002) and lcSSc (1.8% vs 0.3%; P = 0.013), but not in dcSSc or by antibody profile. Factors independently associated with the CC included older age at SSc diagnosis, increased prevalence of early SSc and very early SSc subsets, tobacco exposure and higher medication use of calcium channel blockers, renin-angiotensin-aldosterone system inhibitors, specific vasodilators and immunosuppressants.

This study provides compelling evidence of a significant decline in SRC prevalence and cumulative incidence over time in SSc patients, particularly in definite-SSc patients and lcSSc patients. Factors associated with the CC are described.