Vetter, Thomas R MD, MPH; Adhami, Lalleh F. MD; Porterfield, John R. Jr MD, MSPH; Marques, Marisa B. MD
More than 5 million individuals receive a blood transfusion annually in the United States.1 Approximately, 15 million packed red blood cell units are transfused annually in the United States, and 85 million units worldwide.2–4 Although blood transfusion is a common therapeutic intervention, and specifically, a mainstay of treating surgical blood loss, it is not without risk.1,5 Known risks and adverse events with allogeneic transfusions include transfusing an incorrect blood product, inappropriate and unnecessary transfusion, transfusion-transmitted infection, acute allergic and hemolytic reactions, transfusion-related circulatory overload (TACO), transfusion-related acute lung injury (TRALI), and effects on immunomodulation (e.g., postoperative infection and tumor progression).6,7 Given the risks of transfusion, it is not surprising that many patients have concerns about receiving blood products and want to be adequately informed and directly involved in the transfusion decision-making process.8,9 However, the risks versus benefits of blood transfusion are not always clear, and informed consent may not be obtained satisfactorily.1
The desire for patients to be involved in their care requires that their clinicians be aware of and responsive to individual patient preferences, needs, and values. Practicing such patient-centered care also necessitates that the clinician have an appreciation for an individual patient’s perceptions of transfusion practice.1
Yet little research has been undertaken to assess patients’ perceptions of blood transfusions.10 Specifically, minimal attention has focused on patients’ perceptions of the risks associated with receiving blood products.11 The limited historical data suggest that a substantial proportion of people do not consider the practice of blood transfusion to be safe, citing the risk of contracting an infection such as human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) as a major concern.12
Surgical patients are of particular interest because they comprise a substantial percentage of transfusion recipients.13 To date, we are not aware of other studies that have sought to determine the factors associated with surgical patients’ perceptions of blood transfusion. Recognizing the factors that influence patient perceptions of the risks of blood transfusion could enable health professionals to better educate them and ultimately create a shared responsibility for the patient’s health. In this study, we hypothesized (1) that preoperative patients’ perceptions of transfusion are associated with age, sex, race, education level, and blood donor status and (2) that preoperative patients’ perceptions of transfusion differ from those of their anesthesiologists and surgeons. We, therefore, surveyed a cross-section of surgical patients and physicians about their transfusion-related knowledge and attitudes.
This study was approved by the IRB of the University of Alabama at Birmingham (UAB). A waiver of informed consent documentation was granted by the UAB IRB, with a standardized study information sheet, serving as the written informed consent for patient study subjects. Written informed consent was obtained from all clinician study subjects before participation via the initial page of the online electronic survey.
The administered paper patient survey and the electronic clinician surveya were essentially identical and evaluated: (1) demographic information; (2) perceptions of the overall risk of blood transfusions; (3) level of concern about 5 known adverse events with blood transfusion; and (4) perceptions of the frequency of these 5 adverse events with blood transfusion. The 5 adverse events included allergic reaction (“hives”), fever, dyspnea (“trouble breathing”), HIV/AIDS or hepatitis, and medical error (“given wrong blood”). The term dyspnea (trouble breathing) was used as a proxy for adverse events like TRALI and TACO. There were no questions that specifically addressed shared decision-making. No question was included in the patient survey regarding the risk of donating blood.
A 5 point Likert-scale14,15 was used by all survey respondents to generate a transfusion-related: (a) risk score (1 = never risky, 2 = rarely risky, 3 = sometimes risky, 4 = very often risky, 5 = always risky); (b) adverse event concern score (1 = not concerned, 2 = a little concerned, 3 = moderately concerned, 4 = concerned, 5 = very concerned); and (c) adverse event frequency score (1 = never happens, 2 = rarely happens, 3 = happens sometimes, 4 = happens very often, 5 = happens every time).
Survey Validity Testing
The 2 administered study surveys were questionnaires about knowledge and attitudes. The content and face validity of the surveys were assessed and agreed on by an experienced anesthesiologist (TRV), surgeon (JRP), and transfusion medicine specialist (MBM). Criterion validity is the extent to which one measure estimates or predicts the values of another measure or quality. Concurrent validity is one type of criterion validity, in which the data from both measures are collected at about the same time.16 The concurrent validity of our patient survey was assessed with a Spearman rank correlation between the level of concern about the 5 identified adverse events with blood transfusion (independent variable) and the perceived frequency of these 5 adverse events with blood transfusions (dependent variable). The patients’ level of concern was significantly correlated with their perceived frequency for allergic reaction (r = 0.52, P < 0.001), fever (r = 0.40, P < 0.001), dyspnea (r = 0.46, P < 0.001), HIV/AIDS or hepatitis (r = 0.49, P < 0.001), and medical error (r = 0.48, P < 0.001). No pilot testing of the patient or physician surveys was done.
This anonymous, self-administered, paper survey was offered to a sequential sample of all patients presenting during a 1-month period for routine evaluation at the 2 UAB Preoperative Assessment, Consultation, and Treatment Clinics before a wide variety of surgical procedures. The survey was completed and collected while the patient was waiting to be seen in these 2 clinics. A study investigator was available on-site to address any questions or concerns the participants had while completing the survey. Patients with a history of hematologic disorders such as sickle cell disease or hemophilia were not asked to participate in the study. Jehovah’s Witness patients were not excluded, and their prevalence was not recorded.
Potential clinician study participants were recruited from the full-time faculty in the UAB School of Medicine Departments of Anesthesiology and Surgery, with the resulting cross-sectional, convenience sample, representing clinicians directly involved in the perioperative continuum of care. The 2 physician specialty groups were invited to participate in this study via an e-mail from the principal investigator (MBM). The e-mail described the purpose of the study and provided the recipient with a hyperlink to the online electronic survey located on surveymonkey.com. To maximize the clinician response rate with this census survey, 3 e-mail invitations were sent over a 2-month period to all potential participants. The clinician survey responses were also anonymous.
Continuous variables were reported by using mean and standard deviation (SD). Categorical variables were reported by using frequency counts and percentages. Parametric continuous demographic data were compared between groups by using a t test. Categorical demographic data and binary (yes/no) survey responses were compared between groups by using a χ2 test or Fisher exact test.
For further analysis purposes, the collected patients’ and physicians’ overall transfusion risk scores were collapsed into the 2 dependent outcome categories of never/rarely/sometimes risky (raw scores of 1, 2, and 3) and very often/always risky (raw scores of 4 and 5). The adverse event concern scores were collapsed into the 2 dependent outcome categories of not concerned/a little concerned/moderately concerned (raw scores of 1, 2, and 3) and concerned/very concerned (raw scores of 4 and 5). The adverse event frequency scores were collapsed into the 2 dependent outcome categories of never happens/rarely happens/happens sometimes (raw scores of 1, 2, and 3) and happens very often/happens every time (raw scores of 4 and 5). These cut-points were chosen to reflect the most clinically meaningful differences in scale values.
A binary logistic regression model was used to assess the association between these dichotomized patient-reported overall transfusion-related risk scores and adverse event concern scores versus patient age (54 years and younger/55 years and older, based on the surveyed patients’ mean age of 55 years); sex (female/male); race (African American/Caucasian); education level (high school or less/college or graduate school); and blood donor status (yes/no). The logistic regression models used a backward elimination method.
To evaluate the possible interaction between patient race and education level, an independent interaction term (race*education) was created and entered in Block 2 of 2 of the logistic regression for overall transfusion-related risk scores, with African American = 0 and Caucasian = 1, and high school or less education = 0 and postsecondary education = 1. African Americans with a high school or less education thus served as the reference value.
The group difference in the preoperative patients’ and their physicians’ perception of the overall level of risk associated with blood transfusion was compared with a χ2 test. Group differences in patients’ versus their physicians’ level of concern about and perceived frequency of the 5 specific adverse events associated with blood transfusion were compared with a χ2 test or Fisher exact test. A Spearman rank correlation was performed between physicians’ age and their overall blood transfusion risk score.
No a priori sample size determination and power analysis were performed. However, based on historical preoperative clinic patient volumes, it was expected that a 1-month sampling period would allow for a representative patient sample. For the logistic regression models, a P-value <0.05 was considered significant. For all univariate data analyses, a more conservative P-value <0.01 was considered significant. Statistical analyses were performed by using IBM® SPSS® Version 20.0 (Armonk, New York).
Demographics of Patient Survey Respondents
Of the 328 recruited preoperative patients, 294 completed the patient blood transfusion survey (90% response rate) during their routine visit in February and March 2012 to the UAB Preoperative Assessment, Consultation, and Treatment Clinic (Table 1). The mean age of the patient participants was 55 years, and the sample was predominantly female. Most patients were Caucasians, and African Americans were the most common minority. The enrolled patients were scheduled to undergo a variety of surgical procedures, including general surgical (28%), gynecologic (16%), otolaryngological (15%), neurosurgical (11%), thoracic/vascular (10%), urologic (7%), plastic (4%), orthopedic (3%), and other (6%). Among the surveyed patients, 24% (95% confidence interval [CI], 10%–36%) had previously personally received a blood transfusion, and 95% (95% CI, 93%–98%) would undergo a transfusion if recommended by their physician. However, only 18% (95% CI, 14%–23%) of the surveyed patients were aware of alternatives to blood transfusion.
Patients’ Perception of Transfusion Risk and Patient Characteristics Associated with Perceived Transfusion Risk
Among the 294 surveyed patients, 20% (95% CI, 15%–25%) perceived blood transfusions as being either “very often risky” (score of 4) or “always risky” (score of 5).
Patients’ perceptions of overall blood transfusion risk varied across demographic characteristics (Table 2). African American race (P = 0.028) and having a high school or less level of education (P = 0.022) were significantly associated with greater perceived overall blood transfusion risk. When the race*education term was entered into our logistic regression model, African Americans with a high school or less education perceived blood transfusion as being associated with significant overall risk (adjusted odds ratio = 7.07; 95% CI, 1.89–30.67; P = 0.004). This sensitivity analysis increases confidence in the validity of this observed association.
In our study, because the sample sizes were the same, the observed magnitudes of difference and P-values were closely related. For example, the mean rank for African Americans’ raw ordinal score (1 to 5 scale range) for overall transfusion risk was 167.1 versus the mean rank for Caucasians’ raw ordinal score (1 to 5 scale range) for overall transfusion risk was 135.8 (P = 0.006, Wilcoxon-Mann-Whitney test).
Patient Characteristics Associated with Concern About Transfusion-Related Adverse Events
Patients’ level of concern about specific blood transfusion-related adverse events varied across demographic characteristics (Table 3). African American race (P = 0.001) and having a high school or less level of education (P = 0.009) were significantly associated with a greater concern about allergic reaction. African American race (P < 0.001) and having a high school or less level of education (P = 0.039) were significantly associated with a greater concern about fever. African American race (P = 0.001) and having a high school or less level of education (P = 0.004) were significantly associated with a greater concern about dyspnea. Having a high school or less level of education (P = 0.003) was significantly associated with a greater concern about HIV/AIDS and hepatitis. Having a high school or less level of education (P = 0.039) was significantly associated with a greater concern about medical error.
Demographics of Physician Survey Respondents
Of the 64 recruited anesthesiologists, 34 completed the physician blood transfusion survey (53% response rate), and of the 89 recruited surgeons, 39 completed the survey (44% response rate), in February and March 2013 (Table 1). As compared with the patient participants, the physicians were younger with a mean age of 47 years (P < 0.001). In contrast to the patient sample, the physician sample was predominantly male (P < 0.001). Among the enrolled physicians, 21 (29%) either personally had, or an immediate family member had, received a blood transfusion. Of note, compared with the patient respondents, the physician respondents were significantly more likely to be blood donors (P < 0.001). Among all physicians surveyed, there was no correlation between physicians’ age and their perception of overall blood transfusion risk (r = −0.15; 95% CI, −0.37 to 0.082; P = 0.23).
Patient Versus Physician Perceptions of Transfusion Risk
Patients and physicians differed in their survey responses (Table 4). Although half of the surveyed physicians considered the patient’s family and friends to be the source of patients’ beliefs and opinions about blood transfusion, patients reported the media and “other” as the most common such source. Physicians reported greater overall blood transfusion risk scores (P = 0.001). Specifically, 19% (95% CI, 7%–32%) more of the surveyed physicians rated blood transfusions as “very often risky” (score of 4) or “always risky” (score of 5). Compared with patients, physicians reported that fever (P < 0.001) occurred more frequently. However, compared with their treating physicians, patients reported a greater specific level of concern about HIV/AIDS or hepatitis (P < 0.001) and perceived that HIV/AIDS or hepatitis (P = 0.006) occurred more frequently.
Despite improvements in blood transfusion safety in the United States, the results of our study indicate that at least 15% of patients and at least 27% of their anesthesiologists/surgeons still perceive transfusion as being very often risky or always risky, with certain patient subgroups having greater concerns about specific transfusion-related risks and adverse events. However, we did not assess the surveyed individuals’ overall risk tolerance (i.e., willingness to assume risk), and we did not assess their perceptions of the comparative risk of a blood transfusion versus, for example, driving a car, taking a commercial airline flight, or owning/using a firearm.
The results of our study thus indicate that anesthesiologists and surgeons perceive the overall risk of blood transfusion to be greater when compared with their surgical patients. However, these treating physicians’ levels of concern about 5 specific transfusion-related adverse events were lower than their patients. This discordance indicates that there may be other significant transfusion concerns among anesthesiologists and surgeons, which were not captured by our survey.
The risks associated with allogeneic packed red blood cell transfusions differ significantly between countries with a low versus high human development index (HDI): an index based on life expectancy, literacy, enrollment in further education, and per capita income.17 In countries with a low HDI, the risk of infection is increased, whereas in countries with a high HDI, immunological reactions are predominant.17 In a country like the United States with a high HDI, the incidence of transfusion-related life-threatening allergic reaction18; fever,19 TACO, and TRALI20–22; HIV, hepatitis B, and hepatitis C23,24; and death as a result of hemolysis25 have been quantified (Table 4, footnote).2,7 In our patient population, TACO and fever are relatively common (1 per 100 transfusions), whereas the risk of TRALI is comparable to that of a motor vehicle fatality (13.1 per 100,000 person-years); the risk of a life-threatening allergic reaction or hepatitis B is comparable to that of a firearm homicide (4 per 100,000 person-years); and the risk of fatal hemolysis, hepatitis C, or HIV is comparable to that of airplane fatalities (1 per 29.4 million flights) and lightning fatalities (2 per 1,000,000 person-years).2 There thus appears to be a need for better patient and physician education about the actual risk of these transfusion-related adverse events for accurate communication and effective shared decision-making to occur between patients and their anesthesiologists and surgeons.
A systematic literature review examined the evidence regarding the causes of such patient misperceptions about blood transfusion.26 The identified studies consistently observed that objective or raw knowledge does not correlate with risk perception, but subjective or calibrated knowledge does.26 It thus appears that it is what people think they know rather than what they actually do know that influences their perception of transfusion risk.26 An overall blood transfusion knowledge score could be developed in preoperative patients, with a validated cut-point. This overall blood transfusion knowledge score could guide preoperative patient education.
Although at least 93% of the currently surveyed patients expressed a willingness to undergo a blood transfusion, there were deficiencies in patient knowledge and associated transfusion fears. Shared decision-making could address these transfusion-related patient misconceptions and concerns. The medical community and public are increasingly embracing shared decision-making, a process by which health care choices are made jointly by the practitioner and patient.27–30 Although frequently culminating in a formal informed consent for treatment, shared decision-making is a broader concept, with 3 essential elements: (1) recognizing and acknowledging that a decision is required; (2) knowing and understanding the best available evidence; and (3) incorporating the patient’s values and preferences into the decision.30 In addition to obtaining the requisite preoperative informed consent for blood transfusion from the patient,1,31,32 all elements of shared decision-making are applicable to surgical blood transfusion. A patient’s preconceived perceptions about transfusion-related risks and adverse events should be addressed before the patient signs an informed consent document. These consent forms could specifically cite risks according to published data. Further research could assess whether such consistent and explicit presentation of transfusion risks not only reduces patients’ perceptions and concerns but also improves their transfusion-related knowledge and satisfaction with health care (or to the contrary—are patients who are transfused but did not know the risks more dissatisfied with their care?).
To achieve the full potential of shared decision-making, including with blood transfusion, more clinicians need training in the approach, and more practices need to be reorganized around the principles of patient engagement. Specifically, educating clinicians about sharing decisions with patients and patient-mediated interventions, like patient decision aids, appear promising for improving clinicians’ adoption of shared decision-making in routine practice.29 Additional research is needed to identify the interventions that are most effective.30 The incorporation of shared decision-making in patient blood management thus represents a promising health services research focus.
Educational brochures about blood transfusion could increase preoperative patient information, with minimal impact on clinical efficiency (throughput), cost, and health care professionals’ time. Such brochures could be placed in outpatient preoperative clinic waiting and examination rooms as well as in preoperative patient information packets.33 On the basis of our present findings, such materials ideally would address the unique concerns of specific patient demographic groups.
There are several alternatives to transfusion, including the use of preoperative medications to increase the patient’s red cell mass.34 However, in our present survey, only 18% of patients were aware of alternatives. Elective surgical procedures offer physicians and patients an opportunity to avoid blood transfusions with proper planning and implementation.35 Preoperatively detected anemia can be evaluated to determine its cause and treated appropriately.36
The Perioperative Surgical Home has been proposed by the American Society of Anesthesiologists and other stakeholders as an innovative, patient-centered model, which integrates the pre-, intra-, and postoperative phases and incorporates shared decision-making across the surgical care continuum.37–39 One key component of such the Perioperative Surgical Home model at our institution is a comprehensive Preoperative Assessment, Consultation, and Treatment Clinic, where patient-tailored education and counseling about surgical blood transfusion is now planned to occur.
Limitations of the present study include the 12-month chronological discordance between the patient and clinician survey data collection. However, the faculty turnover in anesthesiology and surgery departments in our institution was minimal. Although the enrolled patients were scheduled to undergo a variety of surgical procedures, we did not correlate their responses with the likelihood of requiring a blood transfusion during their scheduled surgery. Given the informed consent process, and the voluntary and anonymous nature of the physician survey, no data on respondents versus nonrespondents were collected. Furthermore, in contrast to the very high patient survey response rate, the relatively low survey clinician response rate, particularly from surgeons (44%), potentially undermined the validity of our findings because of nonresponse bias. However, higher physician survey response rates have not been associated with lower response bias,40 and nonresponse bias may be less of a concern in physician surveys than in surveys of the general public.41 Jehovah’s Witness patients were not excluded from the patient survey, and their prevalence was not recorded. Although their responses likely skewed the results of the patient survey questions, the “preconceived notions” of various other subgroups also determined their survey responses. We do not have the power to fully explore the association between specific demographic characteristics and the 5 specific transfusion-related complications, given that some of our CIs are relatively large. Last, our study findings would have been strengthened with additional data on what characterized “other” (32%) versus “media” (31%) as the patients’ self-reported primary source of beliefs and opinions about blood transfusions. Additional research will be beneficial to elucidate this issue.
Understanding patients’ perceptions of blood transfusion and, ultimately, identifying demographic groups with specific concerns will better enable health care professionals to address patient-specific risk during the informed consent process. Therefore, physicians will be able to inform their patients of all available alternative therapies, and to recommend blood management in accordance with the individual patient’s values, beliefs, and fears or concerns.
Name: Thomas R. Vetter, MD, MPH.
Contribution: This author helped design and conduct the study, analyze the data, and write the manuscript.
Attestation: Thomas R. Vetter has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.
Name: Lalleh F. Adhami, MD.
Contribution: This author helped design and conduct the study.
Attestation: Lalleh F. Adhami has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
Name: John R. Porterfield Jr, MD, MSPH.
Contribution: This author helped write the manuscript.
Attestation: John R. Porterfield Jr, reviewed the analysis of the data and approved the final manuscript.
Name: Marisa B. Marques, MD.
Contribution: This author helped design and conduct the study, analyze the data, and write the manuscript.
Attestation: Marisa B. Marques has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.
This manuscript was handled by: Franklin Dexter, MD, PhD.
a The 2 administered surveys are available as an online supplement (Supplement 1 and 2).
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