To investigate (1) whether the increase in serum creatinine observed during cyclosporin A (CsA) therapy was reversible in a group of patients with rheumatoid arthritis (RA) treated before the current guidelines for safe use in RA were developed and (2) whether the application of these guidelines prevents serum creatinine increases in the long term.
Eighty-three RA patients who had started low-dose CsA therapy between September 1990 and October 1992, and who were treated according to guidelines that allowed a 50% rise in serum creatinine, were tested for serum creatinine levels in December 1995 if they had discontinued CsA for at least 3 months. Predictors for irreversibility of renal function were determined by using multiple regression analysis.
The mean level of serum creatinine gradually increased from 69+/-14 (mean+/-S.D.) micromol/l when starting CsA therapy to 88+/-23 micromol/l (28% above baseline) at the moment of CsA discontinuation, and had decreased to 80+/-17 micromol/l (16% above baseline) at follow-up, 35+/-14 months after drug discontinuation. During CsA therapy, the mean level of serum creatinine had increased to 82+/-19 micromol/l (26% above baseline) at 6 months and to 87+/-22 micromol/1 (39% above baseline) at 42 months. The mean CsA dose had decreased from 3.1+/-0.9 mg/kg/day at 6 months to 1.9+/-0.8 mg/kg/day at 42 months. The absolute number of months that serum creatinine levels were > 30% above baseline was an independent predictor for a persistent increase of the serum creatinine after CsA discontinuation. More than 2 months with a serum creatinine increase of > or = 30% resulted in a higher percentage irreversible increase than for less than 2 months with a > or = 30% increase: 27 and 6%, respectively (P < 0.0001).
Long-term low-dose CsA administration in RA patients was associated with an increase in serum creatinine which was partially irreversible after drug discontinuation. The increase in serum creatinine was completely reversible in the patient group that was treated according to the current guidelines for safe use of CsA.