BLOOD DONORS AND BLOOD COLLECTION Predictors of hemoglobin recovery or deferral in blood donors with an initial successful donation Brian Custer,1 Marjorie Bravo,2 Roberta Bruhn,1 Kevin Land,2 Peter Tomasulo,2 and Hany Kamel2
BACKGROUND: Donation eligibility is based on hemoglobin (Hb) level among other factors. This study assesses factors that influence Hb levels among firsttime (FT) donors returning for a second donation. STUDY DESIGN AND METHODS: Allogeneic FT donors who successfully donated a red blood cell (RBC)-containing donation on their index presentation and returned to donate at least once more between August 1, 2009, and July 31, 2012, were included. Interdonation intervals and delta Hb (subsequent donation – index donation value) were calculated. Multivariable logistic regression and survival analysis methods were used to determine factors associated with 1) Hb recovery to preindex donation value or 2) deferral at the second presentation. RESULTS: During the study, 135,040 FT donors returned to donate. Overall, 44% of donors returned with a Hb level at or above their index value (defined as recovery for this study), 48.1% for males and 39.9% for females. Logistic regression revealed that the factor most strongly associated with Hb recovery was index Hb, with lower Hb having much higher odds of recovery. Shorter interdonation intervals were associated with decreased likelihood of recovery. Certain demographic characteristics were also associated with higher odds of recovery. Factors associated with deferral were similar to the factors associated with recovery, except for donor sex. CONCLUSIONS: As early as the second blood donation, allogeneic donors can be differentiated into two subpopulations: those who recover to index Hb levels and those who do not. Current data routinely collected by US blood centers cannot reliably distinguish between the two groups.
A
major goal of donor recruitment is to convert first-time (FT) donors into repeat donors. The pursuit of this objective has been based on evidence indicating that donation is safe. However, concern about the impact of blood donation on body iron stores requires further investigation.1 Studies indicate a high prevalence of iron deficiency in donors, with females and repeat donors at increased risk of iron deficiency even when donation suitability criteria are met.2,3 Current screening protocols for blood donors require measurement of hemoglobin (Hb) or hematocrit (Hct). In the United States the lower limit for predonation Hb is 12.5 g/dL for males and females.4,5 FDA rules are designed to allow for adequate time to recover by requiring a minimum acceptable Hb and interdonation interval.6,7 Although Hb testing by capillary sample is not considered the best measure for larger vasculature Hb, it is currently the most accessible way to screen blood donors and is standard of practice.8,9 Quantitative Hb values using a Hb analyzer (HemoCue 301, HemoCue, Inc., Lake Forest, CA) have been collected on all presenting donors at our blood centers since August 2009. In this study, we analyzed return of Hb to predonation level (recovery) in FT donors who presented to donate at least one more time after a successful red blood cell (RBC)-containing donation and factors associated with recovery or deferral.
ABBREVIATIONS: 2RBC = double red blood cell; BMI = body mass index; BSI = Blood Systems, Inc.; FT = first time; MC = multicomponent procedures that included red blood cells; UBS = United Blood Services; WB = whole blood. From the 1Blood Systems Research Institute, San Francisco, California; and 2Blood Systems, Inc., Scottsdale, Arizona. Address reprint requests to: Brian Custer, Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118; e-mail: [email protected]. Received for publication November 1, 2013; revision received January 24, 2014, and accepted January 24, 2014. doi: 10.1111/trf.12628 © 2014 AABB TRANSFUSION 2014;54:2267-2275. Volume 54, September 2014 TRANSFUSION
2267
CUSTER ET AL.
MATERIALS AND METHODS Blood Systems, Inc. (BSI), is a nonprofit transfusion medicine testing and research organization, collecting approximately 1 million allogeneic donations annually in centers from 18 central, southern, and western states. This analysis was limited to data from United Blood Services (UBS) centers using Progesa (MAK/Progesa, Paris, France) as the blood establishment computer system because selfreported height and weight data as well as other donor and donation characteristics are routinely transferred to the data warehouse (Oracle, Redwood Shores, CA). Other BSI centers collect these data but they were not transferred to the data warehouse during the study period. Annually, UBS donations represent 80% of BSI donations and 6% of the nation’s blood supply. This analysis focused on FT allogeneic donors, defined as persons with no prior successful donation at a UBS center, who gave a red blood cell (RBC) donation on the index donation between August 1, 2009, and July 31, 2012. We assessed time to recovery to index Hb measured before donation in whole blood (WB), double RBC (2RBC), and automated multicomponent procedures that included RBCs (MC). Donors with a subsequent presentation during the study period that included Hb measurement, whether the minimum Hb eligibility criterion was met, were included in the data set. Hereditary hemochromatosis and donations from autologous and therapeutic donors were excluded.
Hb measurement Hb values were measured using a Hb analyzer (HemoCue 301, HemoCue, Inc.) using capillary sampling by finger stick. Hb concentration is measured based on the absorbance of WB at an Hb/HbO2 isosbestic point. This method correlates well with the reference method for Hb determination (International Council for Standardization in Hematology) and has a dynamic range of 0 to 25.6 g/dL.12 If initial donor Hb value meets the criteria for WB donation with no evidence of a technical problem, the measured HemoCue value becomes the result of record. If initial reading fails, the procedure may be repeated once using a new finger stick and if valid becomes the result of record. The acceptable Hb level for both WB and MC donations is at least 12.5 g/dL, while for 2RBC donors the acceptable limit is 12.5 to at least 13.3 g/dL depending on the apheresis machine used.4,5 For 2RBC procedures, donors must meet additional height, weight, and predonation Hct and/or Hb criteria set by the collection device manufacturers that ensure a corporeal RBC mass greater than 1500 and 1600 mL for male and female donors, respectively.
Return to baseline Hb Delta Hb was calculated as the difference between Hb at the subsequent presentation and index donation for each donor. Hb recovery was defined as a more than 0 g/dL Hb difference, indicating at least a return to baseline Hb compared to the index donation.
Donor and donation information Donor and donation information was obtained through the data warehouse using computer software (Sagent Information Studio 5.5.1, Sagent Technology, Inc., Pasadena, CA). Donor and donation records include age, sex, race, ethnicity, prior donation history, height, weight, predonation clinical measurements (pulse, blood pressure, Hb), date and location of donation, donation type, and whether the donation was successful. Blood volume and body mass index (BMI) were calculated from selfreported height and weight.10,11
Interdonation interval Interdonation interval was calculated as the difference in days between the next presentation and the index donation for each donor. This was reported as the number of elapsed days or weeks and also grouped into the following categories: 8 to less than 16, 16 to less than 20, 20 to less than 24, 24 to less than 36, 36 to less than 52, and 52 or more weeks for the groups to coincide with the required waiting periods for donor eligibility for a new WB or MC donation (≥8 weeks) and 2RBC donation (≥16 weeks). 2268
TRANSFUSION Volume 54, September 2014
Statistical analysis Separate analyses were performed based on the donation type at first presentation: WB, 2RBC, or MC and stratified by sex, index Hb, and interdonation interval. We calculated the proportions of recovery and deferral (Hb < 12.5 g/dL at next presentation) and median interdonation interval for those donors whose Hb returned to baseline. We used Kaplan-Meier methods to estimate median time to recovery by index Hb group and sex for each donation type. Multivariable logistic regression analysis was used to determine donor demographics, biometric characteristics, clinical measurements, and donation information factors associated with Hb recovery or deferral. Unadjusted odds ratios (OR) and 95% confidence intervals (95% CIs) were computed for each categorical predictor and provide an assessment of the crude association of each variable with the odds of Hb recovery or deferral. To develop multivariable models, all unadjusted ORs that were significant (p ≤ 0.05) were considered. Potential predictors that were no longer significant when included in the multivariable models were removed until only significant predictors remained. Adjusted ORs for each
22
16,031 (12) 36,485 (27) 32,052 (24) 50,472 (37) 59,536 (44) 6877 (5) 154
18
18
128
20
110 (21) 219 (42) 128 (25) 59 (11) 177 (34) 60 (12) 142 11 (2) 69 (10) 180 (25) 466 (64) 358 (49) 3 (0.4) 123.5
20 Median recovery time (weeks)
* Data are reported as mean (±SD), median (IQR), or number (%). † For Hb of less than 12.5 g/dL upon return. IQR = interquartile range.
26
26
184
28
1,306 (54) 789 (33) 308 (13) 750 (31) 183 (8) 193.5
All FT donors 135,040 15.0 (±1.5) 14.9 (13.9-16.0) Multicomponent Female 726 516 15.9 (±1.2) 14.2 (±1.0) 15.9 (15.2-16.6) 14.0 (13.4-14.8) Male
2RBC Male Female 19,362 2,403 16.0 (±1.2) 14.5 (±0.8) 16.0 (15.2-16.8) 14.4 (13.8-15)
1,789 (9) 4,454 (23) 13,119 (68) 8,764 (45) 47 (0.2) 184
14,688 (23) 28,016 (44) 15,305 (24) 6,088 (9) 25,833 (40) 6,421 (10) 151 147 22 21 1,222 (3) 5,086 (11) 11,196 (23) 30,432 (63) 23,654 (49) 163 (0.3) 140
Histograms of interdonation intervals showed a pattern of peak return on or just after the day the donor was again eligible to donate (Fig. 1A). The pattern is variable for MC because some may have returned in fewer than 56 days and donated platelets and/or plasma, since after donating 1 RBC unit a donor may donate by any procedure for which the potential RBC loss is less than 100 mL. For all donation types there is a second peak of donors returning at 1 year, reflecting annual blood drives. For each donation type, the histogram was similar for males and females. Lower index Hb level is associated with shorter median recovery times for males and females who donated WB, 2RBC, or MC. Time to Hb recovery represented in the Kaplan-Meier graphs (Fig. 1B) showed shorter median recovery time for males. For females with high index Hb a substantial proportion did not recover to baseline during the up to 3-year period for return. Males with lower index Hb who recovered had shorter
Female 64,097 14.1 (±1.0) 14.0 (13.3-14.7)
Distribution of return times and median time to Hb recovery
WB
During the study period, there were 135,040 FT donors who successfully donated WB (83%), 2RBC (16%), and MC (1%) on their first presentation and returned to donate a second time. The majority of WB donors were female (57%) while for 2RBC and MC donations the majority of donors were male, 89 and 58%, respectively (Table 1). Of the total, 6915 (5%) donors were deferred for low Hb at the second presentation and 128,125 successfully donated. For males, the mean Hb values were higher (15.9 for WB, 16 for 2RBC, and 15.9 for MC) compared to females (14.1 for WB, 14.5 for 2RBC, and 14.2 for MC). Median Hb and the proportion of the population in each index Hb group by collection type and sex are also provided. At the successful second donation, a higher proportion of males showed Hb recovery (49% for WB, 45% for 2RBC, and 49% for MC) compared to females (40% for WB, 31% for 2RBC, and 34% for MC). Of donors returning 8 to less than 16 weeks after successful WB donation, Hb recovery was observed in 48 and 36% of males and females, respectively; of donors returning 8 to less than 16 weeks after successful MC donation, Hb recovery was observed in 52 and 29%, respectively, and of donors returning 16 to less than 20 weeks after successful 2RBC donation, Hb recovery was observed in 46 and 27%, respectively.
Male 47,936 15.9 (±1.3) 15.9 (15-16.7)
RESULTS
Donor and donation characteristics Total donors (N) Mean index Hb (g/dL) Median index Hb Index Hb groups 12.5-13.2 13.3-14.4 14.5-15.4 ≥15.5 Donors who recovered Donors who were deferred† Median recovery time (days)
significant factor with separate models for each donation type, WB, MC, or 2RBC, are reported. All data preparation and analyses were performed using computer software (STATA SE 12.1, StataCorp, College Station, TX; and Excel 2010, Microsoft Corp., Redmond, WA).
TABLE 1. Study population characteristics including Hb recovery and deferral proportion and median recovery time by index Hb, sex, and donation type for FT donors returning for a second donation attempt
Hb RECOVERY IN FIRST-TIME DONORS
Volume 54, September 2014 TRANSFUSION
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MALE Whole Blood
FEMALE
Fig. 1. Histograms and Kaplan-Meier time to return graphs by donation type and sex. (A) Histogram of donation interval frequency. The solid line in each plot is a smoothed line using kernel density. (B) Time to return
A
Kaplan-Meier graphs for next presentation to donate by index Hb group.
Whole blood
◀
interdonation intervals compared to females with the same donation type and index Hb group. Median recovery time differed by donation type with 2RBC having the longest overall median recovery time of 26 weeks while MC had the shortest with 18 weeks. Regardless of donation type, the median interval to Hb recovery was approximately 2 weeks longer for females than for males (Table 1).
B
2 Unit RBC
Double red cells
A
B
Multi-component
Multicomponents
A
Mean and 95% CIs of delta Hb based on index Hb, sex, and donation type show differences in groups defined by these characteristics (Fig. 2). Males and females with lower index Hb had greater delta Hb than donors with higher index Hb, and males had higher average delta Hb values than females across all index Hb groups. For all donation types, donors with at least 15.5 g/dL Hb had a negative delta Hb with the greatest negative change in Hb of −1.4 g/dL (95% CI, −1.5 to −1.2) in female 2RBC donors at index and −1.4 (95% CI, −1.7 to −1.1) in female donors who gave by MC. Female donors showed a mean small positive difference when their levels were between 12.5 and 13.2 g/dL for WB of 0.16 (95% CI, 0.14-0.18). For all other Hb groups, females showed a mean negative delta Hb.
Delta Hb by interdonation interval Only male WB donors who returned at 52 weeks or longer had a mean positive delta Hb value (+0.08; 95% CI, 0.04-0.11). All other interval groups on average had CIs that were either negative or bridged delta Hb of 0 (Fig. 3). Males had higher delta Hb compared to females across all groups. For both WB and 2RBC, the lowest delta Hb levels were recorded between 20 and 24 weeks postdonation. After 24 weeks the delta Hb for both males and females became less negative. Due to the small number of MC donations the CIs for the delta Hb are wide.
B
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Delta Hb by index Hb
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Hb RECOVERY IN FIRST-TIME DONORS
WB and 2RBC, males were more likely to recover compared to females (OR, 5.7; 95% CI, 3.9-8.4). To assess the sensitivity of the results for factors associated with recovery and to account for potential Hb measurement variability, we relaxed the definition of recovery. In this analysis, we included 20% of the donors below our original cutoff of delta Hb of 0. A total of 14,549 donors with delta Hb between 0 and –0.3 g/dL were included in this new definition of recovery, increasing the number recovered to 74,085. The multivariable logistic regression models for each index donaFig. 2. Mean and 95% CIs of delta Hb by index Hb, sex, and index phlebotomy type. tion type were rerun. The results were similar with the most important factor Predictors of Hb recovery being index Hb level followed by the same hierarchy factors associated with recovery. The ORs for recovery Factors significantly associated with recovery for index across all factors were similar with very minor changes in WB donors include sex, interdonation interval, index Hb, the numerical estimates (data not shown). race, ethnicity, age, BMI, and blood collection location (Table 2). Donors with index Hb of 12.5 to 13.3 g/dL were 14.1 times (95% CI, 13.4-14.9) more likely to recover Hb Predictors of Hb deferral than donors with index Hb of at least 15.5 g/dL. Donors with index Hb of 13.3 to 14.4 g/dL (OR, 6.6; 95% CI, 6.3While donor deferral for low Hb after a successful first 6.9) and index Hb of 14.5-15.4 g/dL (OR, 3.0; 95% CI, 2.9donation was less common than recovery, many of the 3.1) were also more likely to recover than donors with factors associated with deferral are similar to factors assoindex Hb of at least 15.5. Males were more likely to recover ciated with recovery (Table 3). The factor most strongly compared to females (OR, 5.1; 95% CI, 4.9-5.3). The factors associated with deferral was the index Hb level. Compared that showed decreased ORs include interdonation interval to persons with Hb levels of at least 15 g/dL, WB and MC of less than 24 weeks, black or African-American race, donors with index Hb between 12.5 and 13.2 and 2RBC donors 16 to 18 years of age, or 65 or more years of age, and donors with index Hb of 13.3 to 14.4 were far more likely to BMI of at least 40 kg/m2. The factors that showed minibe deferred: WB OR of 20.0 (95% CI, 16.3-24.4), MC OR of 17.9 (95% CI, 3.6-88.8), and 2RBC OR of 11.2 (95% mally increased OR (i.e.,
BACKGROUND: Donation eligibility is based on hemoglobin (Hb) level among other factors. This study assesses factors that influence Hb levels among firsttime (FT) donors returning for a second donation. STUDY DESIGN AND METHODS: Allogeneic FT donors who successfully donated a red blood cell (RBC)-containing donation on their index presentation and returned to donate at least once more between August 1, 2009, and July 31, 2012, were included. Interdonation intervals and delta Hb (subsequent donation – index donation value) were calculated. Multivariable logistic regression and survival analysis methods were used to determine factors associated with 1) Hb recovery to preindex donation value or 2) deferral at the second presentation. RESULTS: During the study, 135,040 FT donors returned to donate. Overall, 44% of donors returned with a Hb level at or above their index value (defined as recovery for this study), 48.1% for males and 39.9% for females. Logistic regression revealed that the factor most strongly associated with Hb recovery was index Hb, with lower Hb having much higher odds of recovery. Shorter interdonation intervals were associated with decreased likelihood of recovery. Certain demographic characteristics were also associated with higher odds of recovery. Factors associated with deferral were similar to the factors associated with recovery, except for donor sex. CONCLUSIONS: As early as the second blood donation, allogeneic donors can be differentiated into two subpopulations: those who recover to index Hb levels and those who do not. Current data routinely collected by US blood centers cannot reliably distinguish between the two groups.
A
major goal of donor recruitment is to convert first-time (FT) donors into repeat donors. The pursuit of this objective has been based on evidence indicating that donation is safe. However, concern about the impact of blood donation on body iron stores requires further investigation.1 Studies indicate a high prevalence of iron deficiency in donors, with females and repeat donors at increased risk of iron deficiency even when donation suitability criteria are met.2,3 Current screening protocols for blood donors require measurement of hemoglobin (Hb) or hematocrit (Hct). In the United States the lower limit for predonation Hb is 12.5 g/dL for males and females.4,5 FDA rules are designed to allow for adequate time to recover by requiring a minimum acceptable Hb and interdonation interval.6,7 Although Hb testing by capillary sample is not considered the best measure for larger vasculature Hb, it is currently the most accessible way to screen blood donors and is standard of practice.8,9 Quantitative Hb values using a Hb analyzer (HemoCue 301, HemoCue, Inc., Lake Forest, CA) have been collected on all presenting donors at our blood centers since August 2009. In this study, we analyzed return of Hb to predonation level (recovery) in FT donors who presented to donate at least one more time after a successful red blood cell (RBC)-containing donation and factors associated with recovery or deferral.
ABBREVIATIONS: 2RBC = double red blood cell; BMI = body mass index; BSI = Blood Systems, Inc.; FT = first time; MC = multicomponent procedures that included red blood cells; UBS = United Blood Services; WB = whole blood. From the 1Blood Systems Research Institute, San Francisco, California; and 2Blood Systems, Inc., Scottsdale, Arizona. Address reprint requests to: Brian Custer, Blood Systems Research Institute, 270 Masonic Avenue, San Francisco, CA 94118; e-mail: [email protected]. Received for publication November 1, 2013; revision received January 24, 2014, and accepted January 24, 2014. doi: 10.1111/trf.12628 © 2014 AABB TRANSFUSION 2014;54:2267-2275. Volume 54, September 2014 TRANSFUSION
2267
CUSTER ET AL.
MATERIALS AND METHODS Blood Systems, Inc. (BSI), is a nonprofit transfusion medicine testing and research organization, collecting approximately 1 million allogeneic donations annually in centers from 18 central, southern, and western states. This analysis was limited to data from United Blood Services (UBS) centers using Progesa (MAK/Progesa, Paris, France) as the blood establishment computer system because selfreported height and weight data as well as other donor and donation characteristics are routinely transferred to the data warehouse (Oracle, Redwood Shores, CA). Other BSI centers collect these data but they were not transferred to the data warehouse during the study period. Annually, UBS donations represent 80% of BSI donations and 6% of the nation’s blood supply. This analysis focused on FT allogeneic donors, defined as persons with no prior successful donation at a UBS center, who gave a red blood cell (RBC) donation on the index donation between August 1, 2009, and July 31, 2012. We assessed time to recovery to index Hb measured before donation in whole blood (WB), double RBC (2RBC), and automated multicomponent procedures that included RBCs (MC). Donors with a subsequent presentation during the study period that included Hb measurement, whether the minimum Hb eligibility criterion was met, were included in the data set. Hereditary hemochromatosis and donations from autologous and therapeutic donors were excluded.
Hb measurement Hb values were measured using a Hb analyzer (HemoCue 301, HemoCue, Inc.) using capillary sampling by finger stick. Hb concentration is measured based on the absorbance of WB at an Hb/HbO2 isosbestic point. This method correlates well with the reference method for Hb determination (International Council for Standardization in Hematology) and has a dynamic range of 0 to 25.6 g/dL.12 If initial donor Hb value meets the criteria for WB donation with no evidence of a technical problem, the measured HemoCue value becomes the result of record. If initial reading fails, the procedure may be repeated once using a new finger stick and if valid becomes the result of record. The acceptable Hb level for both WB and MC donations is at least 12.5 g/dL, while for 2RBC donors the acceptable limit is 12.5 to at least 13.3 g/dL depending on the apheresis machine used.4,5 For 2RBC procedures, donors must meet additional height, weight, and predonation Hct and/or Hb criteria set by the collection device manufacturers that ensure a corporeal RBC mass greater than 1500 and 1600 mL for male and female donors, respectively.
Return to baseline Hb Delta Hb was calculated as the difference between Hb at the subsequent presentation and index donation for each donor. Hb recovery was defined as a more than 0 g/dL Hb difference, indicating at least a return to baseline Hb compared to the index donation.
Donor and donation information Donor and donation information was obtained through the data warehouse using computer software (Sagent Information Studio 5.5.1, Sagent Technology, Inc., Pasadena, CA). Donor and donation records include age, sex, race, ethnicity, prior donation history, height, weight, predonation clinical measurements (pulse, blood pressure, Hb), date and location of donation, donation type, and whether the donation was successful. Blood volume and body mass index (BMI) were calculated from selfreported height and weight.10,11
Interdonation interval Interdonation interval was calculated as the difference in days between the next presentation and the index donation for each donor. This was reported as the number of elapsed days or weeks and also grouped into the following categories: 8 to less than 16, 16 to less than 20, 20 to less than 24, 24 to less than 36, 36 to less than 52, and 52 or more weeks for the groups to coincide with the required waiting periods for donor eligibility for a new WB or MC donation (≥8 weeks) and 2RBC donation (≥16 weeks). 2268
TRANSFUSION Volume 54, September 2014
Statistical analysis Separate analyses were performed based on the donation type at first presentation: WB, 2RBC, or MC and stratified by sex, index Hb, and interdonation interval. We calculated the proportions of recovery and deferral (Hb < 12.5 g/dL at next presentation) and median interdonation interval for those donors whose Hb returned to baseline. We used Kaplan-Meier methods to estimate median time to recovery by index Hb group and sex for each donation type. Multivariable logistic regression analysis was used to determine donor demographics, biometric characteristics, clinical measurements, and donation information factors associated with Hb recovery or deferral. Unadjusted odds ratios (OR) and 95% confidence intervals (95% CIs) were computed for each categorical predictor and provide an assessment of the crude association of each variable with the odds of Hb recovery or deferral. To develop multivariable models, all unadjusted ORs that were significant (p ≤ 0.05) were considered. Potential predictors that were no longer significant when included in the multivariable models were removed until only significant predictors remained. Adjusted ORs for each
22
16,031 (12) 36,485 (27) 32,052 (24) 50,472 (37) 59,536 (44) 6877 (5) 154
18
18
128
20
110 (21) 219 (42) 128 (25) 59 (11) 177 (34) 60 (12) 142 11 (2) 69 (10) 180 (25) 466 (64) 358 (49) 3 (0.4) 123.5
20 Median recovery time (weeks)
* Data are reported as mean (±SD), median (IQR), or number (%). † For Hb of less than 12.5 g/dL upon return. IQR = interquartile range.
26
26
184
28
1,306 (54) 789 (33) 308 (13) 750 (31) 183 (8) 193.5
All FT donors 135,040 15.0 (±1.5) 14.9 (13.9-16.0) Multicomponent Female 726 516 15.9 (±1.2) 14.2 (±1.0) 15.9 (15.2-16.6) 14.0 (13.4-14.8) Male
2RBC Male Female 19,362 2,403 16.0 (±1.2) 14.5 (±0.8) 16.0 (15.2-16.8) 14.4 (13.8-15)
1,789 (9) 4,454 (23) 13,119 (68) 8,764 (45) 47 (0.2) 184
14,688 (23) 28,016 (44) 15,305 (24) 6,088 (9) 25,833 (40) 6,421 (10) 151 147 22 21 1,222 (3) 5,086 (11) 11,196 (23) 30,432 (63) 23,654 (49) 163 (0.3) 140
Histograms of interdonation intervals showed a pattern of peak return on or just after the day the donor was again eligible to donate (Fig. 1A). The pattern is variable for MC because some may have returned in fewer than 56 days and donated platelets and/or plasma, since after donating 1 RBC unit a donor may donate by any procedure for which the potential RBC loss is less than 100 mL. For all donation types there is a second peak of donors returning at 1 year, reflecting annual blood drives. For each donation type, the histogram was similar for males and females. Lower index Hb level is associated with shorter median recovery times for males and females who donated WB, 2RBC, or MC. Time to Hb recovery represented in the Kaplan-Meier graphs (Fig. 1B) showed shorter median recovery time for males. For females with high index Hb a substantial proportion did not recover to baseline during the up to 3-year period for return. Males with lower index Hb who recovered had shorter
Female 64,097 14.1 (±1.0) 14.0 (13.3-14.7)
Distribution of return times and median time to Hb recovery
WB
During the study period, there were 135,040 FT donors who successfully donated WB (83%), 2RBC (16%), and MC (1%) on their first presentation and returned to donate a second time. The majority of WB donors were female (57%) while for 2RBC and MC donations the majority of donors were male, 89 and 58%, respectively (Table 1). Of the total, 6915 (5%) donors were deferred for low Hb at the second presentation and 128,125 successfully donated. For males, the mean Hb values were higher (15.9 for WB, 16 for 2RBC, and 15.9 for MC) compared to females (14.1 for WB, 14.5 for 2RBC, and 14.2 for MC). Median Hb and the proportion of the population in each index Hb group by collection type and sex are also provided. At the successful second donation, a higher proportion of males showed Hb recovery (49% for WB, 45% for 2RBC, and 49% for MC) compared to females (40% for WB, 31% for 2RBC, and 34% for MC). Of donors returning 8 to less than 16 weeks after successful WB donation, Hb recovery was observed in 48 and 36% of males and females, respectively; of donors returning 8 to less than 16 weeks after successful MC donation, Hb recovery was observed in 52 and 29%, respectively, and of donors returning 16 to less than 20 weeks after successful 2RBC donation, Hb recovery was observed in 46 and 27%, respectively.
Male 47,936 15.9 (±1.3) 15.9 (15-16.7)
RESULTS
Donor and donation characteristics Total donors (N) Mean index Hb (g/dL) Median index Hb Index Hb groups 12.5-13.2 13.3-14.4 14.5-15.4 ≥15.5 Donors who recovered Donors who were deferred† Median recovery time (days)
significant factor with separate models for each donation type, WB, MC, or 2RBC, are reported. All data preparation and analyses were performed using computer software (STATA SE 12.1, StataCorp, College Station, TX; and Excel 2010, Microsoft Corp., Redmond, WA).
TABLE 1. Study population characteristics including Hb recovery and deferral proportion and median recovery time by index Hb, sex, and donation type for FT donors returning for a second donation attempt
Hb RECOVERY IN FIRST-TIME DONORS
Volume 54, September 2014 TRANSFUSION
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MALE Whole Blood
FEMALE
Fig. 1. Histograms and Kaplan-Meier time to return graphs by donation type and sex. (A) Histogram of donation interval frequency. The solid line in each plot is a smoothed line using kernel density. (B) Time to return
A
Kaplan-Meier graphs for next presentation to donate by index Hb group.
Whole blood
◀
interdonation intervals compared to females with the same donation type and index Hb group. Median recovery time differed by donation type with 2RBC having the longest overall median recovery time of 26 weeks while MC had the shortest with 18 weeks. Regardless of donation type, the median interval to Hb recovery was approximately 2 weeks longer for females than for males (Table 1).
B
2 Unit RBC
Double red cells
A
B
Multi-component
Multicomponents
A
Mean and 95% CIs of delta Hb based on index Hb, sex, and donation type show differences in groups defined by these characteristics (Fig. 2). Males and females with lower index Hb had greater delta Hb than donors with higher index Hb, and males had higher average delta Hb values than females across all index Hb groups. For all donation types, donors with at least 15.5 g/dL Hb had a negative delta Hb with the greatest negative change in Hb of −1.4 g/dL (95% CI, −1.5 to −1.2) in female 2RBC donors at index and −1.4 (95% CI, −1.7 to −1.1) in female donors who gave by MC. Female donors showed a mean small positive difference when their levels were between 12.5 and 13.2 g/dL for WB of 0.16 (95% CI, 0.14-0.18). For all other Hb groups, females showed a mean negative delta Hb.
Delta Hb by interdonation interval Only male WB donors who returned at 52 weeks or longer had a mean positive delta Hb value (+0.08; 95% CI, 0.04-0.11). All other interval groups on average had CIs that were either negative or bridged delta Hb of 0 (Fig. 3). Males had higher delta Hb compared to females across all groups. For both WB and 2RBC, the lowest delta Hb levels were recorded between 20 and 24 weeks postdonation. After 24 weeks the delta Hb for both males and females became less negative. Due to the small number of MC donations the CIs for the delta Hb are wide.
B
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Delta Hb by index Hb
TRANSFUSION Volume 54, September 2014
Hb RECOVERY IN FIRST-TIME DONORS
WB and 2RBC, males were more likely to recover compared to females (OR, 5.7; 95% CI, 3.9-8.4). To assess the sensitivity of the results for factors associated with recovery and to account for potential Hb measurement variability, we relaxed the definition of recovery. In this analysis, we included 20% of the donors below our original cutoff of delta Hb of 0. A total of 14,549 donors with delta Hb between 0 and –0.3 g/dL were included in this new definition of recovery, increasing the number recovered to 74,085. The multivariable logistic regression models for each index donaFig. 2. Mean and 95% CIs of delta Hb by index Hb, sex, and index phlebotomy type. tion type were rerun. The results were similar with the most important factor Predictors of Hb recovery being index Hb level followed by the same hierarchy factors associated with recovery. The ORs for recovery Factors significantly associated with recovery for index across all factors were similar with very minor changes in WB donors include sex, interdonation interval, index Hb, the numerical estimates (data not shown). race, ethnicity, age, BMI, and blood collection location (Table 2). Donors with index Hb of 12.5 to 13.3 g/dL were 14.1 times (95% CI, 13.4-14.9) more likely to recover Hb Predictors of Hb deferral than donors with index Hb of at least 15.5 g/dL. Donors with index Hb of 13.3 to 14.4 g/dL (OR, 6.6; 95% CI, 6.3While donor deferral for low Hb after a successful first 6.9) and index Hb of 14.5-15.4 g/dL (OR, 3.0; 95% CI, 2.9donation was less common than recovery, many of the 3.1) were also more likely to recover than donors with factors associated with deferral are similar to factors assoindex Hb of at least 15.5. Males were more likely to recover ciated with recovery (Table 3). The factor most strongly compared to females (OR, 5.1; 95% CI, 4.9-5.3). The factors associated with deferral was the index Hb level. Compared that showed decreased ORs include interdonation interval to persons with Hb levels of at least 15 g/dL, WB and MC of less than 24 weeks, black or African-American race, donors with index Hb between 12.5 and 13.2 and 2RBC donors 16 to 18 years of age, or 65 or more years of age, and donors with index Hb of 13.3 to 14.4 were far more likely to BMI of at least 40 kg/m2. The factors that showed minibe deferred: WB OR of 20.0 (95% CI, 16.3-24.4), MC OR of 17.9 (95% CI, 3.6-88.8), and 2RBC OR of 11.2 (95% mally increased OR (i.e.,
