- Email: [email protected]
Mild reactions to blood donation predict a decreased likelihood of donor return
Transfusion and Apheresis Science 30 (2004) 17–22 www.elsevier.com/locate/transci
Mild reactions to blood donation predict a decreased likelihood of donor return Christopher R. France a
a,*
, Janis L. France a, Marios Roussos b, Blaine Ditto
b
Ohio University, 245 Porter Hall, Athens, OH 45701, USA McGill University, Montreal, Quebec, H3A 1B1 Canada
b
Received 1 July 2003; accepted 1 August 2003
Abstract A growing body of evidence suggests that episodes of fainting can deter volunteer blood donors from returning to donate in the future. In contrast, relatively little is known about the effect of significantly more common mild reactions (e.g., faintness, dizziness, lightheadedness) on donor retention. In the present study, 1052 volunteer blood donors completed a standardized measure of subjective physiological reactions immediately after blood donation (Blood Donation Reactions Inventory), and individual scores were used to predict repeat donation behavior during a one-year follow-up. Results of a logistic regression analysis indicated that higher scores on the Blood Donation Reactions Inventory were associated with a significantly lower likelihood of repeat donation, and that novice donors who scored highest on the scale were less than half as likely to have returned to donate in the following year. These findings suggest that the Blood Donation Reactions Inventory is an effective method of assessing reactions that predict donor nonreturn, and therefore may be a useful addition to future studies aimed at enhancing donor satisfaction and retention. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Blood donation reactions; Prediction; Donor retention
1. Introduction Data from the decade leading up to 2000 reveal a narrowing gap between the volume of blood collected and the number of units transfused in the United States each year [1]. Whereas the overall picture suggests that the blood supply meets existing demand, in fact the system suffers from
* Corresponding author. Tel.: +1-740-593-1079; fax: +1-740593-0579/1079. E-mail address: [email protected] (C.R. France).
potentially serious intermittent shortages of specific blood types, variations in regional demand, and seasonal variations in donations [2]. Although more than half of all men and women are eligible to donate blood, it is estimated that only five percent actually do so [3]. Thus, ongoing recruitment and retention of new donors is essential to maintaining an adequate blood supply. Unfortunately, recent evidence suggests that it is becoming increasingly difficult to retain firsttime donors [4,5], with over half of all new blood donors failing to donate a second time [6,7]. Although a number of factors may dissuade novice
1473-0502/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.transci.2003.08.014
18
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22
blood donors from donating again in the future, the occurrence of unpleasant physical reactions during the donation process is believed to be a particularly important impediment to retention [6,8–14]. Whereas fainting is perhaps the most recognizable form of an unpleasant reaction, it is also a relatively rare phenomenon that affects less than 1% of donors [12,15,16]. In contrast, related mild reactions such as dizziness, weakness, and lightheadedness are considerably more common, and are known to be associated with decreased intentions to donate in the future [6,13] and fewer actual repeat donations [9,10,14]. In a recent survey of over 30,000 blood donors, one of the strongest predictors of intention to donate again was donor perception of physical well being [6]. For example, first-time donors who rated their physical well being during or after the donation as ‘‘fair to poor’’ were more than three times as likely as other donors to indicate a low likelihood of future donation. Unfortunately, this study did not assess actual rates of repeat donations. Piliavin and Callero [9] did examine repeat donation behavior in small samples of college and high school donors. In this study mild reactions were judged by the phlebotomists, and the authors report that these reactions involved ‘‘. . . feelings of nausea, dizziness, and disorientation, and are visible to the attentive nurse by sweating and a rather distinctive greenish tinge to the skin.’’ (p. 111). When the authors collapsed their data across all groups, they discovered that donors who experienced a mild reaction were significantly less likely to have donated again up to two years later when compared with those who did not experience a mild reaction. Although mild reactions appear to be important in the prediction of donor retention, it is difficult to accurately gauge their impact using existing donor databases. This is because blood collection agencies use diverse definitions of donor reactions, and depending on the definition used, a mild reaction may refer to a wide range of symptoms with or without loss of consciousness (e.g., the American Red Cross recently adopted a revised definition of ‘‘light’’ reaction that may or may not include a loss of consciousness for up to one minute). A second limitation regarding existing
databases is that phlebotomist ratings may have inherent limitations in predicting donor behavior. First, while a phlebotomist can detect overt signs of vasovagal reactions or donor distress, they may not be able to detect subtle subjective symptoms such as dizziness or lightheadedness. Second, ratings made by an external observer do not account for the subjective intensity of the donorsÕ reactions. That is, a donor may appear to have very mild symptoms from the phlebotomistÕs perspective, yet the donor may judge the same symptoms as sufficiently disturbing that they are deterred from donating in the future. Finally, despite their best intentions, phlebotomists may be biased toward underreporting donor reactions given that some donor reactions may be viewed as a sign of poor technical skill. In sum, although there is preliminary support for the notion that mild physical reactions are related to donor attrition, to date there are no empirical investigations of the relationship between subjective physical reactions and the likelihood of a subsequent donation. The present study examines this relationship using data from a separate investigation in which volunteers were asked to complete a standardized measure of subjective physiological reactions, the Blood Donation Reactions Inventory, shortly after donating blood. Donor reaction ratings are used to predict the likelihood of a repeat donation during a one-year follow-up period.
2. Methods 2.1. Participants Volunteer blood donors (n ¼ 1052) were recruited from donation clinics conducted in Montreal, Canada by the local blood collection agency, Hema-Quebec. A majority of participants in the study were female (57.7%), and, because the drives were conducted at local colleges and universities, the sample included a large proportion of young adults as well as novice, or first-time, blood donors (33.7%). Demographic characteristics of the sample are provided in Table 1.
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22 Table 1 Descriptive characteristics of age, systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), body mass index (BMI), and number of prior donations for donors in the study Variable (units)
Age (years) SBP (mm Hg) DBP (mm Hg) HR (bpm) BMI (kg/m2 ) Prior donations
All donors (n ¼ 1052)
Novice donors only (n ¼ 355)
Mean (SD)
Mean (SD)
23.1 117.7 73.2 74.7 23.6 3.7
19.9 116.8 72.5 74.7 23.5 –
(8.6) (11.9) (9.0) (12.6) (4.2) (7.8)
(4.3) (11.3) (8.8) (12.8) (4.5)
2.2. Study design and treatments Participants were recruited at the donation clinic prior to their health-screening interview. After providing informed consent, participants completed a questionnaire regarding demographic information (e.g., age, sex, height, weight) and a brief scale concerning pre-donation anxiety. Two seated blood pressure and heart rate measurements were then obtained using a B-D Assure (Model A10) portable blood pressure monitor. After donating blood according to standard Hema-Quebec blood collections protocols, participants completed the Blood Donations Reactions Inventory as well as a measure of venipuncture pain while seated in the post-donation refreshment area. The Blood Donation Reactions Inventory [13,17] asks the donor to rate 11 subjective physiological reactions associated with blood donation, including faintness, dizziness, weakness, facial flush, visual disturbance (such as blurred vision or tunnel vision), difficulty hearing, lightheadedness, rapid or pounding heartbeat, sweating, rapid or difficult breathing, nausea or upset stomach. Participants rate the degree to which they experienced each of these symptoms on a 0 ‘‘not at all’’ to 5 ‘‘to an extreme degree’’ scale, and individual ratings are summed to create a total score. This scale has demonstrated strong internal consistency (a ¼ 0:93), and concurrent validity for this instrument has been established based on significant correlations with phlebotomist ratings of donor reactions [17].
19
Following the donation, data was obtained from the Hema-Quebec personnel and donor database concerning: (1) whether or not the donorÕs chair was reclined by the phlebotomist in response to vasovagal symptoms and (2) whether or not each donor donated blood again in the oneyear follow-up interval.
3. Statistical methods To examine the relationship between donor characteristics and likelihood of a subsequent donation during the one-year follow-up, a forward-entry logistic regression analysis was conducted. Potential predictor variables included donor sex, body mass index, donation experience, pre-donation systolic blood pressure and heart rate, pre-donation anxiety, venipuncture pain rating, and Blood Donation Reactions Inventory score. Age was not included due to a high correlation, r ¼ 0:64, p < 0:001, with donation experience. The dependent variable was donor return within the one-year follow-up interval (return ¼ 1; non-return ¼ 0). To further examine the effect of subjective reactions on donor return behavior, subgroups were created based on cut-off scores on the Blood Donation Reactions Inventory. A Kruskal–Wallis test was used to compare the proportion of returning and non-returning donors across groups, and follow-up analyses were conducted using Mann–Whitney U tests. Similar Mann–Whitney U tests were conducted to examine the relationship between phlebotomist chair reclining and donor return behavior.
4. Results 4.1. Predictors of repeat donation Only three of the potential predictor variables entered the final regression as significant predictors, with Blood Donation Reactions Inventory score entering as the strongest predictor on step 1, donation experience on step 2, and body mass
20
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22
index on step 3. In the final equation the odds ratio (OR) for the Blood Donations Reactions Inventory score was 0.96, (95% CI, 0.94–0.98, p < 0:001), which reflects a 4% decrease in likelihood of donor return for every one-point increase on the rating scale. Donation experience was associated with an OR ¼ 1.04 (95% CI, 1.02–1.07, p < 0:005), indicating a 4% increase in likelihood of a repeat donation per unit increase in the number of prior donations. Finally, body mass index was associated with an OR ¼ 1.04 (95% CI, 1.00–1.07, p < 0:05), which indicated a 4% increase in likelihood of donor return per unit increase in body mass. Interestingly, the same predictor variables emerged, with similar odds ratios, when this analysis was repeated while: (1) controlling for whether or not the donation chair was reclined or (2) excluding the small number of donors (n ¼ 36) who reported a loss of consciousness while donating.
Fig. 1. Percentage of donors who returned to give blood within a one-year interval as a function of Blood Donation Reactions Inventory (BDRI) scores at the initial donation. For both novice donors and the entire sample, those who scored less than 10 on the BDRI were significantly more likely to donate again than those who scored 10 or above.
4.2. Predicting repeat donations using the blood donation reactions inventory
4.3. Predicting repeat donation using phlebotomist chair reclining
To examine the specific effects of subjective reactions to donation on return behavior, donor subgroups were created based on Blood Donation Reactions Inventory scores less than 10, between 10 and 19, and 20 or above. Results of a Kruskal– Wallis test revealed that the proportion of donors who returned to give blood within one-year decreased significantly with increasing scores on the Blood Donation Reactions Inventory (all donors: v2 ð2; N ¼ 1052Þ ¼ 26:5, p < 0:001; novice donors: v2 ð2; N ¼ 355Þ ¼ 15:88, p < 0:001). As illustrated in Fig. 1, this effect held for all donors combined as well as novice donors considered separately. For all donors, those who scored below 10 returned to give blood at a rate of 55% as compared to 35% for those who scored between 10 and 19 (Z ¼ 3:31, p < 0:005) and 30% for those who scored 20 or above (Z ¼ 4:19, p < 0:001). For novice donors, those who scored below 10 returned to give blood at a rate of 45% as compared to 22% for those who scored between 10 and 19 (Z ¼ 2:54, p < 0:05) and 19% for those who scored 20 or above (Z ¼ 3:31, p < 0:005).
A phlebotomist may decide to recline a donorÕs chair in response to signs of vasovagal reactions on the part of the donor, hence chair reclining can provide independent confirmation of the donorÕs subjective report of reactions. As a result, we examined the relationship between phlebotomist chair reclining and donor return behavior. As shown in Fig. 2, the proportion of donors who returned to give blood within one-year was significantly higher if their donation chair was not reclined previously. Specifically, amongst all donors, those who did not have their chaired reclined returned to give blood at a significantly higher rate of 55% versus 33% for those who did have their chair reclined (Z ¼ 5:11, p < 0:001). Among novice donors, those who did not have their chaired reclined returned to give blood at a significantly higher rate of 43% versus 30% for those who did have their chair reclined (Z ¼ 2:23, p < 0:05). Not surprisingly, a significant correlation was observed between donor chair reclining and normalized Blood Donation Reactions Inventory scores (r ¼ 0:74, p < 0:001).
60
% Returned at One Year
All Donors Novice Donors
50 40 30 20 10 0 0-9
10-19
20+
Blood Donation Reactions Inventory Score
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22 60
% Returned at One Year
All Donors Novice Donors
50 40 30 20 10 0 Not Reclined
Reclined
Blood Donation Chair Fig. 2. Percentage of donors who returned to give blood within a one-year interval as a function of whether or not their chair was reclined by the phlebotomist at the initial donation. For both novice donors and the entire sample, donors who did not have their chair reclined were significantly more likely to donate again than those who did.
5. Discussion The present study confirms existing evidence that mild reactions to blood donation predict a decreased likelihood of donor return [6,9], and provides the first evidence that donorsÕ subjective reactions to blood donation can be used to predict retention. Further, results from the logistic regression analysis indicate that donor ratings on the Blood Donation Reactions Inventory may provide a method of quantifying likelihood of non-return, as each unit increase on this scale was associated with a 4% decrease in likelihood of return. Whereas a four percent change per unit increase may appear to be a small effect, it should be noted that this odds ratio translates into a large decrease in donor retention for individuals who score 10 or above versus those who score below 10. For example, as illustrated in Fig. 1, novice donors who scored 10 or above were only half as likely to return at one-year as compared to those who scored less than 10. Further, a 4% decrease per unit change in Blood Donation Reactions Inventory score was comparable in magnitude to the increase in percent likelihood of repeat donation associated with: (1) each prior donation experience or (2) each additional unit of body mass.
21
It is also important to note that the observed relationship between increased reactions and decreased retention was not due to the reports of a few donors who experienced more severe reactions, as the same relationships were observed when the data were reanalyzed without those who reported a loss of consciousness during donation. Similarly, the Blood Donations Reactions Inventory remained a significant predictor of return behavior even after controlling for donation chair reclining. This is an important issue because, as shown in Fig. 2, those who have their chairs reclined are less likely to provide a subsequent donation. In fact, in some cases they may be actively discouraged from future donations by individual phlebotomists or blood collection agency policy (e.g., Hema-Quebec will not allow a donor to donate again if they have had their chair reclined on two consecutive donations). 6. Conclusions The present findings suggest that the Blood Donation Reactions Inventory is an effective tool for quantifying donor reactions and predicting likelihood of repeat donations. However, because these data were collected at blood donation clinics held on college campuses, the sample included a large proportion of young, novice donors. Thus, additional studies are required to determine whether the present findings generalize to larger and more diverse samples of volunteer blood donors. Acknowledgements This research was supported by grants from the Fonds de la Recherche en Sante du Quebec and the Canadian Blood Services. The assistance of Ginette Turgeon of Hema-Quebec is gratefully acknowledged. References [1] Sullivan MT, Umana WO, Greer JI. Comprehensive report on blood collection and transfusion in the United States in 1999. Bethesda, MD: The National Blood Data Resource Center; 2001.
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[2] Simon TL. Where have all the donors gone? A personal reflection on the crisis in AmericaÕs volunteer blood program. Transfusion 2003;43(2):273–9. [3] Linden JV, Gregorio DI, Kalish RI. An estimate of blood donor eligibility in the general population. Vox Sang 1988; 54(2):96–100. [4] Zuck TF, Thomson RA, Schreiber GB, Gilcher RO, Kleinman SH, Murphy EL, et al. The retrovirus epidemiology donor study (REDS): rationale and methods. Transfusion 1995;35(11):944–51. [5] Wu Y, Glynn SA, Schreiber GB, Wright DJ, Lo A, Murphy EL, et al. First-time blood donors: demographic trends. Transfusion 2001;41(3):360–4. [6] Thomson RA, Bethel J, Lo AY, Ownby HE, Nass CC, Williams AE. Retention of ‘‘safe’’ blood donors. The retrovirus epidemiology donor study. Transfusion 1998;38(4): 359–67. [7] Ownby HE, Kong F, Watanabe K, Tu Y, Nass CC. Analysis of donor return behavior. Retrovirus epidemiology donor study. Transfusion 1999;39(10):1128–35. [8] Trouern-Trend JJ, Cable RG, Badon SJ, Newman BH, Popovsky MA. A case-controlled multicenter study of vasovagal reactions in blood donors: influence of sex, age, donation status, weight, blood pressure, and pulse. Transfusion 1999;39(3):316–20.
[9] Piliavin JA, Callero PL. Giving blood: the development of an altruistic identity. Baltimore: Johns Hopkins; 1991. [10] Piliavin JA. Why do they give the gift of life? A review of research on blood donors since 1977. Transfusion 1990;30(5):444–59. [11] Kaloupek DG, Stoupakis T. Coping with a stressful medical procedure: further investigation with volunteer blood donors. J Behav Med 1985;8(2):131–48. [12] Ogata H, Iinuma N, Nagashima K, Akabane T. Vasovagal reactions in blood donors. Transfusion 1980;20(6):679–83. [13] Sauer LA, France CR. Caffeine attenuates vasovagal reactions in female first-time blood donors. Health Psychol 1999;18(4):403–9. [14] Staallekker LA, Stammeijer RN, Dudok de Wit C. A Dutch blood bank and its donors. Transfusion 1980;20(1): 66–70. [15] Kasprisin DO, Glynn SH, Taylor F, Miller KA. Moderate and severe reactions in blood donors. Transfusion 1992; 32(1):23–6. [16] Newman BH, Graves S. A study of 178 consecutive vasovagal syncopal reactions from the perspective of safety. Transfusion 2001;41(12):1475–9. [17] Meade MA, France CR, Peterson LM. Predicting vasovagal reactions in volunteer blood donors. J Psychosom Res 1996;40(5):495–501.
Mild reactions to blood donation predict a decreased likelihood of donor return Christopher R. France a
a,*
, Janis L. France a, Marios Roussos b, Blaine Ditto
b
Ohio University, 245 Porter Hall, Athens, OH 45701, USA McGill University, Montreal, Quebec, H3A 1B1 Canada
b
Received 1 July 2003; accepted 1 August 2003
Abstract A growing body of evidence suggests that episodes of fainting can deter volunteer blood donors from returning to donate in the future. In contrast, relatively little is known about the effect of significantly more common mild reactions (e.g., faintness, dizziness, lightheadedness) on donor retention. In the present study, 1052 volunteer blood donors completed a standardized measure of subjective physiological reactions immediately after blood donation (Blood Donation Reactions Inventory), and individual scores were used to predict repeat donation behavior during a one-year follow-up. Results of a logistic regression analysis indicated that higher scores on the Blood Donation Reactions Inventory were associated with a significantly lower likelihood of repeat donation, and that novice donors who scored highest on the scale were less than half as likely to have returned to donate in the following year. These findings suggest that the Blood Donation Reactions Inventory is an effective method of assessing reactions that predict donor nonreturn, and therefore may be a useful addition to future studies aimed at enhancing donor satisfaction and retention. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Blood donation reactions; Prediction; Donor retention
1. Introduction Data from the decade leading up to 2000 reveal a narrowing gap between the volume of blood collected and the number of units transfused in the United States each year [1]. Whereas the overall picture suggests that the blood supply meets existing demand, in fact the system suffers from
* Corresponding author. Tel.: +1-740-593-1079; fax: +1-740593-0579/1079. E-mail address: [email protected] (C.R. France).
potentially serious intermittent shortages of specific blood types, variations in regional demand, and seasonal variations in donations [2]. Although more than half of all men and women are eligible to donate blood, it is estimated that only five percent actually do so [3]. Thus, ongoing recruitment and retention of new donors is essential to maintaining an adequate blood supply. Unfortunately, recent evidence suggests that it is becoming increasingly difficult to retain firsttime donors [4,5], with over half of all new blood donors failing to donate a second time [6,7]. Although a number of factors may dissuade novice
1473-0502/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.transci.2003.08.014
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C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22
blood donors from donating again in the future, the occurrence of unpleasant physical reactions during the donation process is believed to be a particularly important impediment to retention [6,8–14]. Whereas fainting is perhaps the most recognizable form of an unpleasant reaction, it is also a relatively rare phenomenon that affects less than 1% of donors [12,15,16]. In contrast, related mild reactions such as dizziness, weakness, and lightheadedness are considerably more common, and are known to be associated with decreased intentions to donate in the future [6,13] and fewer actual repeat donations [9,10,14]. In a recent survey of over 30,000 blood donors, one of the strongest predictors of intention to donate again was donor perception of physical well being [6]. For example, first-time donors who rated their physical well being during or after the donation as ‘‘fair to poor’’ were more than three times as likely as other donors to indicate a low likelihood of future donation. Unfortunately, this study did not assess actual rates of repeat donations. Piliavin and Callero [9] did examine repeat donation behavior in small samples of college and high school donors. In this study mild reactions were judged by the phlebotomists, and the authors report that these reactions involved ‘‘. . . feelings of nausea, dizziness, and disorientation, and are visible to the attentive nurse by sweating and a rather distinctive greenish tinge to the skin.’’ (p. 111). When the authors collapsed their data across all groups, they discovered that donors who experienced a mild reaction were significantly less likely to have donated again up to two years later when compared with those who did not experience a mild reaction. Although mild reactions appear to be important in the prediction of donor retention, it is difficult to accurately gauge their impact using existing donor databases. This is because blood collection agencies use diverse definitions of donor reactions, and depending on the definition used, a mild reaction may refer to a wide range of symptoms with or without loss of consciousness (e.g., the American Red Cross recently adopted a revised definition of ‘‘light’’ reaction that may or may not include a loss of consciousness for up to one minute). A second limitation regarding existing
databases is that phlebotomist ratings may have inherent limitations in predicting donor behavior. First, while a phlebotomist can detect overt signs of vasovagal reactions or donor distress, they may not be able to detect subtle subjective symptoms such as dizziness or lightheadedness. Second, ratings made by an external observer do not account for the subjective intensity of the donorsÕ reactions. That is, a donor may appear to have very mild symptoms from the phlebotomistÕs perspective, yet the donor may judge the same symptoms as sufficiently disturbing that they are deterred from donating in the future. Finally, despite their best intentions, phlebotomists may be biased toward underreporting donor reactions given that some donor reactions may be viewed as a sign of poor technical skill. In sum, although there is preliminary support for the notion that mild physical reactions are related to donor attrition, to date there are no empirical investigations of the relationship between subjective physical reactions and the likelihood of a subsequent donation. The present study examines this relationship using data from a separate investigation in which volunteers were asked to complete a standardized measure of subjective physiological reactions, the Blood Donation Reactions Inventory, shortly after donating blood. Donor reaction ratings are used to predict the likelihood of a repeat donation during a one-year follow-up period.
2. Methods 2.1. Participants Volunteer blood donors (n ¼ 1052) were recruited from donation clinics conducted in Montreal, Canada by the local blood collection agency, Hema-Quebec. A majority of participants in the study were female (57.7%), and, because the drives were conducted at local colleges and universities, the sample included a large proportion of young adults as well as novice, or first-time, blood donors (33.7%). Demographic characteristics of the sample are provided in Table 1.
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22 Table 1 Descriptive characteristics of age, systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), body mass index (BMI), and number of prior donations for donors in the study Variable (units)
Age (years) SBP (mm Hg) DBP (mm Hg) HR (bpm) BMI (kg/m2 ) Prior donations
All donors (n ¼ 1052)
Novice donors only (n ¼ 355)
Mean (SD)
Mean (SD)
23.1 117.7 73.2 74.7 23.6 3.7
19.9 116.8 72.5 74.7 23.5 –
(8.6) (11.9) (9.0) (12.6) (4.2) (7.8)
(4.3) (11.3) (8.8) (12.8) (4.5)
2.2. Study design and treatments Participants were recruited at the donation clinic prior to their health-screening interview. After providing informed consent, participants completed a questionnaire regarding demographic information (e.g., age, sex, height, weight) and a brief scale concerning pre-donation anxiety. Two seated blood pressure and heart rate measurements were then obtained using a B-D Assure (Model A10) portable blood pressure monitor. After donating blood according to standard Hema-Quebec blood collections protocols, participants completed the Blood Donations Reactions Inventory as well as a measure of venipuncture pain while seated in the post-donation refreshment area. The Blood Donation Reactions Inventory [13,17] asks the donor to rate 11 subjective physiological reactions associated with blood donation, including faintness, dizziness, weakness, facial flush, visual disturbance (such as blurred vision or tunnel vision), difficulty hearing, lightheadedness, rapid or pounding heartbeat, sweating, rapid or difficult breathing, nausea or upset stomach. Participants rate the degree to which they experienced each of these symptoms on a 0 ‘‘not at all’’ to 5 ‘‘to an extreme degree’’ scale, and individual ratings are summed to create a total score. This scale has demonstrated strong internal consistency (a ¼ 0:93), and concurrent validity for this instrument has been established based on significant correlations with phlebotomist ratings of donor reactions [17].
19
Following the donation, data was obtained from the Hema-Quebec personnel and donor database concerning: (1) whether or not the donorÕs chair was reclined by the phlebotomist in response to vasovagal symptoms and (2) whether or not each donor donated blood again in the oneyear follow-up interval.
3. Statistical methods To examine the relationship between donor characteristics and likelihood of a subsequent donation during the one-year follow-up, a forward-entry logistic regression analysis was conducted. Potential predictor variables included donor sex, body mass index, donation experience, pre-donation systolic blood pressure and heart rate, pre-donation anxiety, venipuncture pain rating, and Blood Donation Reactions Inventory score. Age was not included due to a high correlation, r ¼ 0:64, p < 0:001, with donation experience. The dependent variable was donor return within the one-year follow-up interval (return ¼ 1; non-return ¼ 0). To further examine the effect of subjective reactions on donor return behavior, subgroups were created based on cut-off scores on the Blood Donation Reactions Inventory. A Kruskal–Wallis test was used to compare the proportion of returning and non-returning donors across groups, and follow-up analyses were conducted using Mann–Whitney U tests. Similar Mann–Whitney U tests were conducted to examine the relationship between phlebotomist chair reclining and donor return behavior.
4. Results 4.1. Predictors of repeat donation Only three of the potential predictor variables entered the final regression as significant predictors, with Blood Donation Reactions Inventory score entering as the strongest predictor on step 1, donation experience on step 2, and body mass
20
C.R. France et al. / Transfusion and Apheresis Science 30 (2004) 17–22
index on step 3. In the final equation the odds ratio (OR) for the Blood Donations Reactions Inventory score was 0.96, (95% CI, 0.94–0.98, p < 0:001), which reflects a 4% decrease in likelihood of donor return for every one-point increase on the rating scale. Donation experience was associated with an OR ¼ 1.04 (95% CI, 1.02–1.07, p < 0:005), indicating a 4% increase in likelihood of a repeat donation per unit increase in the number of prior donations. Finally, body mass index was associated with an OR ¼ 1.04 (95% CI, 1.00–1.07, p < 0:05), which indicated a 4% increase in likelihood of donor return per unit increase in body mass. Interestingly, the same predictor variables emerged, with similar odds ratios, when this analysis was repeated while: (1) controlling for whether or not the donation chair was reclined or (2) excluding the small number of donors (n ¼ 36) who reported a loss of consciousness while donating.
Fig. 1. Percentage of donors who returned to give blood within a one-year interval as a function of Blood Donation Reactions Inventory (BDRI) scores at the initial donation. For both novice donors and the entire sample, those who scored less than 10 on the BDRI were significantly more likely to donate again than those who scored 10 or above.
4.2. Predicting repeat donations using the blood donation reactions inventory
4.3. Predicting repeat donation using phlebotomist chair reclining
To examine the specific effects of subjective reactions to donation on return behavior, donor subgroups were created based on Blood Donation Reactions Inventory scores less than 10, between 10 and 19, and 20 or above. Results of a Kruskal– Wallis test revealed that the proportion of donors who returned to give blood within one-year decreased significantly with increasing scores on the Blood Donation Reactions Inventory (all donors: v2 ð2; N ¼ 1052Þ ¼ 26:5, p < 0:001; novice donors: v2 ð2; N ¼ 355Þ ¼ 15:88, p < 0:001). As illustrated in Fig. 1, this effect held for all donors combined as well as novice donors considered separately. For all donors, those who scored below 10 returned to give blood at a rate of 55% as compared to 35% for those who scored between 10 and 19 (Z ¼ 3:31, p < 0:005) and 30% for those who scored 20 or above (Z ¼ 4:19, p < 0:001). For novice donors, those who scored below 10 returned to give blood at a rate of 45% as compared to 22% for those who scored between 10 and 19 (Z ¼ 2:54, p < 0:05) and 19% for those who scored 20 or above (Z ¼ 3:31, p < 0:005).
A phlebotomist may decide to recline a donorÕs chair in response to signs of vasovagal reactions on the part of the donor, hence chair reclining can provide independent confirmation of the donorÕs subjective report of reactions. As a result, we examined the relationship between phlebotomist chair reclining and donor return behavior. As shown in Fig. 2, the proportion of donors who returned to give blood within one-year was significantly higher if their donation chair was not reclined previously. Specifically, amongst all donors, those who did not have their chaired reclined returned to give blood at a significantly higher rate of 55% versus 33% for those who did have their chair reclined (Z ¼ 5:11, p < 0:001). Among novice donors, those who did not have their chaired reclined returned to give blood at a significantly higher rate of 43% versus 30% for those who did have their chair reclined (Z ¼ 2:23, p < 0:05). Not surprisingly, a significant correlation was observed between donor chair reclining and normalized Blood Donation Reactions Inventory scores (r ¼ 0:74, p < 0:001).
60
% Returned at One Year
All Donors Novice Donors
50 40 30 20 10 0 0-9
10-19
20+
Blood Donation Reactions Inventory Score
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% Returned at One Year
All Donors Novice Donors
50 40 30 20 10 0 Not Reclined
Reclined
Blood Donation Chair Fig. 2. Percentage of donors who returned to give blood within a one-year interval as a function of whether or not their chair was reclined by the phlebotomist at the initial donation. For both novice donors and the entire sample, donors who did not have their chair reclined were significantly more likely to donate again than those who did.
5. Discussion The present study confirms existing evidence that mild reactions to blood donation predict a decreased likelihood of donor return [6,9], and provides the first evidence that donorsÕ subjective reactions to blood donation can be used to predict retention. Further, results from the logistic regression analysis indicate that donor ratings on the Blood Donation Reactions Inventory may provide a method of quantifying likelihood of non-return, as each unit increase on this scale was associated with a 4% decrease in likelihood of return. Whereas a four percent change per unit increase may appear to be a small effect, it should be noted that this odds ratio translates into a large decrease in donor retention for individuals who score 10 or above versus those who score below 10. For example, as illustrated in Fig. 1, novice donors who scored 10 or above were only half as likely to return at one-year as compared to those who scored less than 10. Further, a 4% decrease per unit change in Blood Donation Reactions Inventory score was comparable in magnitude to the increase in percent likelihood of repeat donation associated with: (1) each prior donation experience or (2) each additional unit of body mass.
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It is also important to note that the observed relationship between increased reactions and decreased retention was not due to the reports of a few donors who experienced more severe reactions, as the same relationships were observed when the data were reanalyzed without those who reported a loss of consciousness during donation. Similarly, the Blood Donations Reactions Inventory remained a significant predictor of return behavior even after controlling for donation chair reclining. This is an important issue because, as shown in Fig. 2, those who have their chairs reclined are less likely to provide a subsequent donation. In fact, in some cases they may be actively discouraged from future donations by individual phlebotomists or blood collection agency policy (e.g., Hema-Quebec will not allow a donor to donate again if they have had their chair reclined on two consecutive donations). 6. Conclusions The present findings suggest that the Blood Donation Reactions Inventory is an effective tool for quantifying donor reactions and predicting likelihood of repeat donations. However, because these data were collected at blood donation clinics held on college campuses, the sample included a large proportion of young, novice donors. Thus, additional studies are required to determine whether the present findings generalize to larger and more diverse samples of volunteer blood donors. Acknowledgements This research was supported by grants from the Fonds de la Recherche en Sante du Quebec and the Canadian Blood Services. The assistance of Ginette Turgeon of Hema-Quebec is gratefully acknowledged. References [1] Sullivan MT, Umana WO, Greer JI. Comprehensive report on blood collection and transfusion in the United States in 1999. Bethesda, MD: The National Blood Data Resource Center; 2001.
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