Associations between potential prognostic factors and outcomes were evaluated using Cox proportional hazard regression models. Occurrence of chronic GVHD was included into models as a time-dependent covariate. We used a stepwise procedure at a significance level of 5% to construct prognostic models. The proportional hazards assumption of Cox model was assessed mainly by a graphic approach.

HR indicates hazard ratio; 95% CI, 95% confidence interval; and GVHD, graft-versus-host disease.

The following variables were considered in univariate analysis: recipient age at transplantation; recipient body weight; HLA mismatch; blood type mismatch; sex mismatch; infused nuclear cell dose and CD34⁺ cell dose; primary diseases; stage of primary diseases at transplantation; previous history of hematopoietic transplantation; preparative regimen and GVHD prophylaxis; and previous acute GVHD.

EFS was defined as the time from transplantation to the following events: first progression of the primary diseases, death without progression, and graft failure. Progressions of leukemia and myelodysplastic syndrome were defined as relapse of primary diseases on the basis of morphologic evaluation in the bone marrow or other sites. Progression of malignant lymphoma was defined as involvement of new sites, recurrence in originally involved sites, or increase of more than 25% in original tumor masses. Progression of multiple myeloma was defined as an increase in serum or urine M-component, development of new soft tissue plasmacytomas, and/or increase in the size of soft tissue plasmacytomas.

Nonrelapse mortality was defined as death without progression of the primary diseases.

Those included acute lymphoblastic leukemia (n=347), acute myeloid leukemia (n=323), adult T-cell leukemia (n=28), myelodysplastic syndrome (n=171), chronic myelogenous leukemia (n=50), non-Hodgkin lymphoma (n=117), Hodgkin lymphoma (n=7), and multiple myeloma (n=29).

Disease status at CBT was classified into 3 groups according to the standardized report forms of the International Bone Marrow Transplant Registry (IBMTR).

The early group including first complete remission of acute leukemia and lymphoma, first chronic phase of chronic myeloid leukemia, first complete or partial remission of multiple myeloma, and myelodysplastic syndrome refractory anemia.

The intermediate group including second or subsequent complete remission of acute leukemia and lymphoma, accelerated phase of chronic myeloid leukemia, and second or subsequent complete or partial remission of multiple myeloma.

The advanced group including refractory disease, relapse or partial response of acute leukemia and lymphoma, blastic crisis of chronic myeloid leukemia, and other malignancies.

Those included grade 0 (n=252), grade I (n=297), grade II (n=328), grade III (n=148), and grade IV (n=16).

Those factors were not included in the multivariate prognostic models because those P values did not exceed .05 in univariate analysis.