Objective: Chronic renal disease other than scleroderma renal crisis (SRC) is not well documented in systemic sclerosis (SSc). We examined the occurrence of decreased glomerular filtration rate (GFR) in a large consecutive SSc cohort and analysed whether it was related to SSc or could be related to other causes.
Methods: During 1983-2004 GFR was measured by chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA) or iohexol clearance in 461 patients with SSc according to the American College of Rheumatology (ACR) criteria [356 with limited cutaneous SSc (lcSSc) and 105 with diffuse cutaneous SSc (dcSSc)] and the measurements were repeated once a year. Decreased GFR was defined as GFR<70% of the age-adjusted values. SRC was diagnosed in 4/360 lcSSc (1.1%) and in 10/115 dcSSc (8.7%). These patients were excluded from further analyses.
Results: At the latest follow-up at a median duration of 7.7 (range 0.5-54) years, decreased GFR was found in 39 lcSSc (11%) and nine (8.6%) dcSSc patients. Among the 48 SSc patients with GFR< 70p% (percentage of predicted value = p%), hypertension was diagnosed in 29 (60%) and cardiac involvement in 25 (52%). Different nephropathies were found in eight (19%) patients by renal biopsy. Fifteen patients with decreased GFR were followed up for > or = 4 years and no progress was seen in 11/15.
Conclusions: A minority of patients with SSc develop renal dysfunction other than SRC. Decreased GFR was associated with other manifestations such as hypertension and cardiac involvement indicating possible pre-renal causes.