Genetic and behavioral modification of hemoglobin and iron status among first-time and high-intensity blood donors

The value of genetic data from 665,460 individuals in managing iron deficiency anaemia and suitability to donate blood

BACKGROUND AND OBJECTIVES

Although the genetic determinants of haemoglobin and ferritin have been widely studied, those of the clinically and globally relevant iron deficiency anaemia (IDA) and deferral due to hypohaemoglobinemia (Hb-deferral) are unclear. In this investigation, we aimed to quantify the value of genetic information in predicting IDA and Hb-deferral.

MATERIALS AND METHODS

We analysed genetic data from up to 665,460 participants of the FinnGen, Blood Service Biobank and UK Biobank, and used INTERVAL (N = 39,979) for validation. We performed genome-wide association studies (GWASs) of IDA and Hb-deferral and utilized publicly available genetic associations to compute polygenic scores for IDA, ferritin and Hb. We fitted models to estimate the effect sizes of these polygenic risk scores (PRSs) on IDA and Hb-deferral risk while accounting for the individual's age, sex, weight, height, smoking status and blood donation history.

RESULTS

Significant variants in GWASs of IDA and Hb-deferral appear to be a small subset of variants associated with ferritin and Hb. Effect sizes of genetic predictors of IDA and Hb-deferral are similar to those of age and weight which are typically used in blood donor management. A total genetic score for Hb-deferral was estimated for each individual. The odds ratio estimate between first decile against that at ninth decile of total genetic score distribution ranged from 1.4 to 2.2.

CONCLUSION

The value of genetic data in predicting IDA or suitability to donate blood appears to be on a practically useful level.

Next generation sequencing to identify iron status and individualise blood donors' experience

BACKGROUND

Young adults form the majority of first-time blood donors to Australian Red Cross Lifeblood. However, these donors pose unique challenges for donor safety. Young blood donors, who are still undergoing neurological and physical development, have been found to have lower iron stores, and have higher risks of iron deficiency anaemia when compared to older adults and non-donors. Identifying young donors with higher iron stores may improve donor health and experience, increase donor retention, and reduce the burden on product donation. In addition, these measures could be used to individualise donation frequency.

MATERIALS AND METHODS

Stored DNA samples from young male donors (18-25 years; No.=47) were sequenced using a custom panel of genes identified in the literature to be associated with iron homeostasis. The custom sequencing panel used in this study identified and reported variants to human genome version 19 (Hg19).

RESULTS

82 gene variants were analysed. Only one of which, rs8177181, was found to have a statistically significant (p<0.05) association with plasma ferritin level. Heterozygous alleles of this Transferrin gene variant, rs8177181T>A, significantly predicted a positive effect on ferritin levels (p=0.03).

DISCUSSION

This study identified gene variants involved in iron homeostasis using a custom sequencing panel and analysed their association with ferritin levels in a young male blood donor population. Additional studies of factors associated with iron deficiency in blood donors are required if a goal of personalised blood donation protocols is to be achieved.

Supplemental findings of the 2021 National Blood Collection and Utilization Survey

BACKGROUND

The Department of Health and Human Services' National Blood Collection and Utilization Survey (NBCUS) has been conducted biennially since 1997. Data are used to estimate national blood collection and use. Supplemental data from the 2021 NBCUS not presented elsewhere are presented here.

METHODS

Data on survey participation, donor characteristics, blood component cost, transfusion-associated adverse reactions, and implementation of blood safety measures, including pathogen-reduction of platelets, during 2021, were analyzed. Comparisons are made to 2019 survey data where available (2013-2019 for survey participation).

RESULTS

During 2021, there were 11,507,000 successful blood donations in the United States, a 4.8% increase from 2019. Persons aged 45-64 years accounted for 42% of all successful blood donations. Donations by persons aged 65 years and older increased by 40.7%, while donations among minorities and donors aged <25 years decreased. From 2019 to 2021, the median price hospitals paid per unit of leukoreduced red blood cells, leukoreduced and pathogen-reduced apheresis platelets, and fresh frozen plasma increased. The largest increase in price per unit of blood component in 2021 was for leukoreduced apheresis platelets, which increased by ~$51. Between 2019 and 2021, the proportion of transfusing facilities reporting use of pathogen-reduced platelets increased, from 13% to 60%. Transfusion-related adverse reactions declined slightly between 2019 and 2021, although the rate of transfusion-transmitted bacterial infections remained unchanged.

CONCLUSION

During 2021, blood donations increased nationally, although donations from those aged <25 years and minorities declined. The prices hospitals paid for most blood products increased, as did the use of pathogen-reduced platelets.

Iron Deficiency and Blood Donation: Links, Risks and Management

The purpose of this review is to raise awareness about the frequently underappreciated association of blood donation with iron deficiency, and to describe methods for its prevention and management. Blood donors cannot expect any health benefits from the donation but have justified expectations of no harm. Iron deficiency without anemia (IDWA) and iron deficiency anemia (IDA) are common consequences of regular blood donation, and this activity is the most important factor affecting iron status in regular blood donors. Awareness of blood donation as a primary cause of sideropenia is surprisingly low among physicians. Blood donation screening identifies potential donors with IDA but is frequently inadequate to detect IDWA. For the assessment of body iron stores, plasma or serum ferritin, transferrin saturation (TSAT) and soluble transferrin receptors (sTfR) concentrations are the most widely used biochemical markers, although the percentage of hypochromic mature erythrocytes and the hemoglobin content of reticulocytes are also useful. IDWA can be prevented by limiting the total volume of blood collected, by iron deficiency screening and deferral of sideropenic donors, by prolonging the interdonation intervals, and by iron supplementation between donations. IDWA tends to be more prevalent in younger people, females, and high-intensity donors. A potentially effective strategy to address sideropenia in blood donors is serum ferritin testing, but this may lead to a higher rate of deferral. Most regular blood donors cannot replenish their iron deficit by an iron-rich diet alone and will benefit from low-dose oral iron administration with various commercially available products post-donation, a well-tolerated strategy. However, valid concerns exist regarding the possibility of worsening the iron overload in donors with undiagnosed hemochromatosis or masking the symptoms of a clinically important gastrointestinal hemorrhage or other underlying medical condition. Finally, educational efforts should be intensified to improve the awareness of blood donation as a primary cause of iron deficiency among physicians of all specialties.

Iron status of blood donors

PURPOSE OF REVIEW

This review examines recent research on the prevalence and importance of iron deficiency in blood donors, and on efforts to mitigate it.

RECENT FINDINGS

Premenopausal females, teenagers, and high-frequency donors are at the highest risk for donation-induced iron deficiency, in both high-resource and low-resource settings. The physiology relating iron stores to hemoglobin levels and low hemoglobin deferral is well elucidated in blood donor populations, yet the clinical effects attributable to iron loss in the absence of anemia are challenging to identify. Expanded adoption of ferritin testing is improving donor management but may cause decreases in the blood supply from temporary donor loss. The potential for personalized donor management is emerging with development of computational models that predict individual interdonation intervals that aim to optimize blood collected from each donor while minimizing low hemoglobin deferrals.

SUMMARY

Measures to reduce iron deficiency are available that can be deployed on a standardized or, increasingly, personalized basis. Blood centers, regulators, and donors should continue to evaluate different tactics for addressing this problem, to obtain a balanced approach that is optimal for maintaining adequate collections while safeguarding donor health.

Deferral due to low hemoglobin and predictors of permanence in the blood donation system of repeat female blood donors

OBJECTIVES

To evaluate the deferral rate due to low hemoglobin (Hb) in repeat female blood donors and identify the factors affecting their permanence in the blood donation system.

MATERIALS AND METHODS

8,368 repeat female blood donors who donated from January 2012 to December 2018 were included. Bivariate analysis and Kaplan-Meier curves were used to identify the covariates possibly associated with developing low Hb, and Cox proportional hazards modeling was used to adjust for all confounders.

RESULTS

The global deferral rate due to low Hb was 2.4 %. According to baseline Hb, the frequency of low Hb was 0.7-4.1 %, and it was higher in platelet donors (5.8-9.1 %) than in whole blood donors (1.9 %). The main predictors were baseline Hb (compared to the first quartile; hazard ratio [HR] = 0.487 for the second quartile; 0.234 for the third; and 0.095 for the fourth); change in Hb (HR = 2.689 for a >0.49 g/dL change, compared to smaller changes); the type of donation (compared to whole blood donors, HR = 2.317 for platelet donors); and donation interval (compared to >12.5 month intervals; HR = 2.220 for 8.0-12.5 months; HR = 5.658 for 5.4-8.0 months; and HR = 9.452 for <5.4 months).

CONCLUSIONS

In female blood donors at moderate altitude, the probability of developing low Hb increases with a baseline Hb of 13.5-14.0 g/dL, with a change in Hb >0.49 g/dL, in platelet donors, and with donation intervals <12.5 months. These four predictive factors can be used together for early identification of donors at risk of developing low Hb, to institute appropriate measures.

Supplemental findings of the 2019 National Blood Collection and Utilization Survey

INTRODUCTION

Supplemental data from the 2019 National Blood Collection and Utilization Survey (NBCUS) are presented and include findings on donor characteristics, autologous and directed donations and transfusions, platelets (PLTs), plasma and granulocyte transfusions, pediatric transfusions, transfusion-associated adverse events, cost of blood units, hospital policies and practices, and implementation of blood safety measures, including pathogen reduction technology (PRT).

METHODS

National estimates were produced using weighting and imputation methods for a number of donors, donations, donor deferrals, autologous and directed donations and transfusions, PLT and plasma collections and transfusions, a number of crossmatch procedures, a number of units irradiated and leukoreduced, pediatric transfusions, and transfusion-associated adverse events.

RESULTS

Between 2017 and 2019, there was a slight decrease in successful donations by 1.1%. Donations by persons aged 16-18 decreased by 10.1% while donations among donors >65 years increased by 10.5%. From 2017 to 2019, the median price paid for blood components by hospitals for leukoreduced red blood cell units, leukoreduced apheresis PLT units, and for fresh frozen plasma units continued to decrease. The rate of life-threatening transfusion-related adverse reactions continued to decrease. Most whole blood/red blood cell units (97%) and PLT units (97%) were leukoreduced.

CONCLUSION

Blood donations decreased between 2017 and 2019. Donations from younger donors continued to decline while donations among older donors have steadily increased. Prices paid for blood products by hospitals decreased. Implementation of PRT among blood centers and hospitals is slowly expanding.