Influence of protective isolation on outcome of allogeneic bone marrow transplantation for leukemia.

ABSTRACT

Various isolation strategies are used to prevent infections during bone marrow transplantation; data on their efficacy are lacking. We studied whether use of high efficiency particulate air filtration (HEPA) and/or laminar airflow (LAF) units affect transplant-related mortality (TRM) or survival in the first year after allogeneic transplantation. 5065 patients with leukemia receiving bone marrow transplants from an HLA identical sibling (n = 3982) or alternative related or unrelated donors (n = 1083) between 1988 and 1992 were reported to the International Bone Marrow Transplant Registry by 222 teams. Two types of isolation were considered (1) conventional protective isolation with single patient room and any combination of hand-washing, gloves, mask and gown; and (2) HEPA and/or LAF. Cox proportional hazards regression models were used to determine the relative risks (RRs) of transplant-related mortality (TRM) and of deaths from any cause in patients treated in HEPA/LAF units compared to patients treated in conventional isolation. HLA-identical sibling and alternative donor transplants were analyzed separately. Risks of TRM and overall mortality in the first 100 days post-transplant were significantly lower among patients treated in HEPA/LAF units than in those treated conventionally. RRs of TRM were 0.76 (P = 0.009) for recipients of HLA-identical sibling transplants and 0.65 (P = 0.003) for recipients of alternative donor transplants. Correspondingly RRs of overall mortality were 0.80 (P = 0.02) and 0.65 (P = 0.0006). Decreased risks of TRM and of death in the first 100 days post-transplant resulted in significantly higher 1-year survival rates in patients treated in HEPA/LAF rather than in conventional isolation units. Use of HEPA and/or LAF to prevent infections decreases TRM and increases survival after allogeneic bone marrow transplants for leukemia.