Ideal Body Weight Is Useful For Predicting Neutrophil Engraftment and Platelet Recovery for Overweight and Obese Recipients in Single-Unit Cord Blood Transplantation.

Because cord blood (CB) units are usually selected based on the cell dose per kilogram, overweight (body mass index [BMI] ≥25 kg/mto < 30 kg/m) and obese (30 kg/m ≤ BMI) recipients tend to have difficulty in getting appropriate CB units. In general, actual body weight (ABW) is used for CB unit selection. However, ideal body weight (IBW) has been reported to be more closely correlated with successful engraftment after autologous, allogeneic bone marrow, and peripheral blood stem cell transplantation than ABW. We conducted this analysis to clarify the threshold of CD34 cell doses based on ideal body weight (CD34) and to compare the outcomes among the groups stratified by the threshold according to actual body weight (CD34) and CD34 for overweight and obese recipients in cord blood transplantation (CBT). We retrospectively analyzed 650 overweight and obese recipients who received single-unit CBT. To focus on the recipients who received a low CD34 cell dose/kg, those who received 1.5×10 CD34 cells/ABW or more were excluded. Using a cut-off of 0.8×10 CD34 cells/kg, we compared the outcomes in 3 groups with low CD34 and low CD34 (CD34), low CD34 but high CD34 (CD34), and high CD34 and high CD34 (CD34). Hematopoietic recoveries were significantly delayed in the CD34 group compared with those in the CD34 group (hazard ratio [HR] 0.67 for neutrophil, P < .001; HR 0.72 for platelet, P = .014), whereas those were comparable in the CD34 and CD34 groups (HR 1.22 for neutrophil, P = .16; HR 1.29 for platelet, P = .088). Moreover, the CD34 group demonstrated longer overall survival than the CD34 group (HR 1.48, P = .011) and comparable survival to the CD34 group (HR 0.93, P = .68). This finding may address the lack of availability of CB units for some overweight and obese recipients for whom suitable donors are unavailable. Further investigations are warranted to evaluate the appropriateness of ABW and IBW.