1. Dialysis Unit, Sophiahemmet, Karolinska University Hospital, P.O. Box 5605, 114 86 Stockholm, Sweden
2. Department of Renal Medicine, Karolinska University Hospital, P.O. Box 5605, 141 86 Stockholm, Sweden
3. Swedish Renal Registry (SRR), Medicinexp, plan 5, Länssjukhuset Ryhov, 551 85 Jönköping, Sweden