Background: Autologous peripheral blood hematopoietic progenitor cell (HPC) collection can be impacted by several patient-related factors including age, sex, diagnosis, and prior chemotherapy. To examine the impact of obesity on HPC collection, we performed a retrospective analysis of HPC collections relative to body mass index (BMI). BMI is a heuristic measure of body fat commonly used to diagnose and classify obesity. Methods: A 16-month retrospective review of all adult autologous HPC collections was performed. Procedures were excluded from primary analysis if the patient had received plerixafor within prior 12 h of HPC collection. Patient data included age, sex, weight, height, BMI, diagnosis, total blood volume (BV), mobilization regimen, and peripheral blood counts (WBC, %MNC, %CD34, CD34/lL). Procedure-related information included inlet volume, inlet rate, cell yield (WBC, MNC/kg, CD34 3 10 6 /kg), CD34 collect rate (CD34/kg per peripheral CD34/lL), and procedure-associated adverse events. The overall success rate to collect three million CD34/kg or one transplant was determined using all procedures regardless of plerixafor use.
Data was compared relative to patient BMI classification [normal (NL, BMI 18.5-24.9), overweight (OW, BMI 25-29.9), obese (OB, BMI 30-34.9), severe OB (BMI 35-39.9), and morbid OB (BMI > 40)]. BMI was calculated and classified according to NIH guidelines (www.nhlbi.support.com/bmi). Statistics were performed by t-test, v 2 , and linear regression using commercial software. A P value < 0.05 was considered significant. Results: A total of 165 patients (114 (69%) male, 51 (31%) female) and 299 procedures were available for analysis. The incidence of obesity was 43.7% (OB 5 18.8%, severe OB 5 15.2%, morbid OB 5 9.7%). Morbid OB patients averaged 131 AE 28 kg (P 5 0.027-0.001) with a significantly higher BMI 5 49.2 (P < 0.0001), total BV 5 6456 AE 1359 mL (P 5 0.12-0.005), and inlet volume (17.9 AE 4.1 L, P 5 0.01-0.001). Female donors were increased among morbid OB (44%, P 5 0.07) and NL donors (45%, P 5 0.006). There was no significant difference in mean age, diagnosis, mobilization regimen, peripheral blood counts (WBC, MNC, CD34), or number of BV processed (2.9 AE 0.4) by BMI. There was, however, an inverse relationship between cell yields and BMI. There was a progressive decrease in mean MNC/kg (2.59 to 1.79 3 10 8 /kg, P 5 0.003-0.001) and CD34/kg (4.85 to 1.09 3 10 6 /kg, P 5 0.0009-0.0001) with increasing BMI. Morbid OB showed a significant fourfold decrease in CD34/kg per BV processed (0.37 vs. 1.58, P 5 0.0009 0.00001). Morbid OB also showed a 10fold decrease in CD34 collection rate (slope, m) with increasing BMI: (Fig. 1: NL, (m 5 0.16, ), OW, (m 5 0.17, x), OB, BMI 30 < 40 (m 5 0.14, o), morbid OB, (m 5 0.0015, = 2). Morbid Fig. 1.