Cumulative incidence of hemorrhagic cystitis by donor type. Cumulative incidence was similar for all subgroups during the first month after transplantation; excessive incidence among MUD, MM rel, and UCB became evident after that time period. No cases of hemorrhagic cystitis were documented among matched related donor transplantations after the first month. Cumulative incidence of HC was as follows: MRD, 16% (95% CI 7-35); MM rel, 30% (95% CI 16-58); MUD, 40% (95% CI 27-60); and UCB, 40% (95% CI 22-74). MUD indicates matched unrelated donor; UCB, unrelated cord blood; MM rel, mismatched related (1 antigen mismatch); MRD, matched related donor.