Background: Cyclosporine is an immunosuppressive drug that is used to treat patients with autoimmune disease as well as patients who have received allografts. The drug can cause renal damage, but the incidence of and risk factors for nephropathy in patients treated with cyclosporine for autoimmune or inflammatory diseases are not known.
Methods: We analyzed data from renal biopsies performed in 192 patients (129 adults and 63 children) who had been treated with cyclosporine for insulin-dependent diabetes mellitus of recent onset, uveitis, psoriasis, Sjögren's syndrome, or polychondritis. The mean (+/- SD) initial dose of cyclosporine was 8.2 +/- 2.8 mg per kilogram of body weight per day, and the duration of treatment was 4 to 39 months (median, 13).
Results: Forty-one patients (37 adults and 4 children) had cyclosporine-induced nephropathy, defined as at least moderate focal interstitial fibrosis with tubular atrophy, arteriolar alterations, or both. As compared with patients in whom nephropathy did not develop, these patients received a larger initial dose of cyclosporine (9.3 +/- 2.8 vs. 8.0 +/- 2.8 mg per kilogram per day), had a larger maximal increase in the serum creatinine concentration above base-line values (101 +/- 77 percent vs. 50 +/- 33 percent), and were older (31 +/- 13 vs. 23 +/- 12 years). These three variables were shown by multivariate logistic-regression analysis to be significant risk factors. The duration of the elevation in the serum creatinine concentration and the occurrence of elevated blood pressure were not additional risk factors.
Conclusions: Nephropathy is an important potential effect of cyclosporine therapy. The risk of its development in patients with autoimmune diseases who are treated with cyclosporine can be minimized by allowing a dose no higher than 5 mg per kilogram per day and avoiding increases in serum creatinine of more than 30 percent above the patient's base-line value.