Kidney Disease Other Than Renal Crisis in Patients with Diffuse Scleroderma

Objective: To determine the frequency and severity of kidney abnormalities in patients with diffuse scleroderma.

Methods: All patients with diffuse scleroderma seen at the University of Pittsburgh between 1972 and 1993 were included in the study. Kidney function tests were routinely obtained as part of the Pittsburgh Scleroderma Outcome Study. Additional kidney tests were obtained as part of the 1992 biannual outcome assessment. Patients who had kidney abnormalities including a serum creatinine > 1.2 mg/dl or proteinuria prior to 1993 were identified. The clinical setting and longterm outcome of kidney disease were evaluated.

Results: Renal crisis occurred in 129/675 (19.5%) patients. Kidney function abnormalities or proteinuria were present in 173 (26%); 48% had no abnormalities. Most patients had other explanations for the abnormality. Only 12 (2%) of the 675 patients with diffuse scleroderma had no explanation for the elevated creatinine level. Most patients with proteinuria had toxicity from D-penicillamine. No explanations for proteinuria were found in 16 (2%) of this cohort. Thus, a total of only 28 (4%) of these 675 patients had an unknown cause for their kidney dysfunction or proteinuria. None of these patients, who were followed for a mean of 10 years after onset of scleroderma, have developed chronic renal insufficiency that progressed to dialysis.

Conclusion: Patients with diffuse scleroderma without renal crisis rarely have significant increases in serum creatinine or proteinuria that cannot be explained by other etiologies. These patients with scleroderma should be carefully evaluated for non-scleroderma causes of kidney disease.