Acceptance of the concept of brain death (BD) as the meaning that a person died has been key to organ transplantation, as the majority of organ donors are people who have died and are in BD. However, lack of understanding of this concept is one of the main psychosocial reasons reported against donation, especially in relation to the fear to an only apparent dead.
Among healthcare professionals and medical students, the attitude towards organ donation is relatively positive,1–3 but a significant proportion still lack a full understanding of the concept of BD.1–3 A close association has been described between knowledge about the concept of BD and attitude towards organ donation in almost all social groups.1–4 However, among medical students results have been conflicting. While a Spanish national study2,3 found a clear relationship between knowledge about BD and attitude towards organ donation, many other studies have failed to confirm these findings and have often reported the opposite.2,3,5–8
The aim of this study is to determine the effect of knowledge of the concept of BD has on the attitude of medical students towards donating their own organs by performing a meta-regression analysis.
In order to be included in the meta-regression analysis, studies had to meet the following criteria: 1) report the rate of participants with a favourable attitude towards donating their own organs after death and the rate of participants who were aware of the concept of BD; 2) participants had to be medical students; and 3) the studies had to have an observational methodology with no experimental manipulation.
A search was carried out in the electronic databases PubMed, CINALH Complete and PsycInfo using the following combination of keywords: (Organ Donation AND Attitude AND Medical Students). We reviewed 315 references, of which 19 articles met the inclusion criteria, providing data from 20 samples (Table 1).
Main characteristics of the studies analysing knowledge about the concept of brain death and its relationship with attitude towards organ donation among medical students.
| Author | Citation | Year | Country | N | Know about BD concept | Attitude in favour of organ donation | |
|---|---|---|---|---|---|---|---|
| 1 | Akkas M. | Med Sci Monit. 2018;24:6918-6924 | 2013 | Turkey | 100 | 50% | 54% |
| 100 | 70% | 88% | |||||
| 2 | Atamañuk A. N. | Transplant Proc. 2018;50:2976-2980 | 2016 | Argentina | 1,012 | 58.1% | 81.9% |
| 3 | Bilgel H. | Transplant Med. 2006;18:91−96 | 2004 | Turkey | 409 | 86.5% | 58.4% |
| 4 | Chung C. K. | Hong Kong Med J. 2008;14:278-285 | 2006 | China | 655 | 67.2% | 85% |
| 5 | Dutra M. | Transplant Proc. 2004;36:818-820 | 2002 | Brazil | 779 | 82.4% | 69.2% |
| 6 | Edwards T. M. | J Natl Med Assoc. 2007;99:131-137 | 2005 | USA | 500 | 28% | 82.4% |
| 7 | El-Agroudy A. E. | Saudi J Kidney Dis Transpl. 2019;30:83-96 | 2017 | Bahrain | 376 | 74.5% | 71.8% |
| 8 | Figueroa C. A. | Transplant Proc. 2013;45:2093-2097 | 2011 | The Netherlands | 506 | 46.2% | 79.8% |
| 9 | Kozlik P. | Transplant Proc. 2014;46:2479-2486 | 2012 | Poland | 400 | 85% | 90.5% |
| 10 | Lima C. X. | Transplant Proc. 2010;42:1466-1471 | 2007 | Brazil | 300 | 67% | 62% |
| 11 | Marqués-Lespier J. M. | PRHSJ. 2013;32:187-193 | 2008 | Puerto Rico | 227 | 80% | 88.5% |
| 12 | Najafizadeh K. | Transplant Proc. 2009;41:2707-2710 | 2006 | Iran | 41 | 95.1% | 87.8% |
| 13 | Ohwaki K. | Clin Transplant. 2006;20:416-422 | 2004 | Japan | 388 | 46% | 59% |
| 14 | Ríos A. | Ethn Health. 2019;24:443-461 | 2011 | Spain | 9,275 | 66.7% | 80% |
| 15 | Rydzewska M. | Transplant Proc. 2018;50:1939-1945 | 2016 | Poland | 569 | 22% | 93% |
| 16 | Sahin H. | Exp Clin Transplant. 2015;1-9 | 2013 | Several | 1,541 | 51.3% | 94.4% |
| 17 | Sebastián-Ruiz M. J. | Gac Med Mex. 2017;153:432-442 | 2015 | Mexico | 3,056 | 68% | 74% |
| 18 | Tagizadieh A. | Transplant Proc. 2018;50:2966-2970 | 2016 | Iran | 400 | 57% | 85% |
| 19 | Zhang L. | Transplantation. 2014; 1-8 | 2012 | China | 199 | 67.8% | 32.2% |
Two coders independently extracted the rates of participants with a favourable attitude towards organ donation and the rates of participants who were aware of the concept of BD. The result was the proportion of students in favour. Assuming that the sample of studies represented different populations, the overall effect was calculated with a random effects model, where each study was weighted by its precision, which depended mainly on the sample size. To verify the effect of the percentage of students who were aware of the concept of BD on the result, a meta-regression analysis was carried out under the mixed effects model, calculating the QR statistic and the percentage of variance explained by the moderating variable R2.9 All the data were analysed with the statistical software Comprehensive Meta-Analysis CMA 3.0 (Biostat Inc.).10
The overall magnitude of the effect of the 20 studies yielded a ratio of 0.78 (95% CI: 0.73−0.82), indicating that a combined percentage of 78% of students were in favour of donating their own organs after death. As the heterogeneity analysis showed a high and significant variability between the effect sizes of the studies (Q[19]=853.22, P<.000; I2=97.77%), we went on to check whether or not knowledge about BD was one explanation for the variability.
The results of the meta-regression analysis showed that knowledge about the concept of BD was not a significant predictor of magnitude of the effect (bj=–0.01, Q1=0.78, P=.38), with the percentage of explained variance being 5%. Fig. 1 shows the graph with the line derived from the meta-regression analysis, confirming the absence of association between the variables studied.
Therefore, the differences between the rates of students in favour reported by the studies were not related to the percentage of students who were aware of the concept of BD.
It is striking that several studies show little knowledge about the concept of BD among medical students, whether in the USA,5 in Europe6,7 or in Asia.8 One such study by Edwards et al.5 in the USA reports that only 28% understood the concept, while in the Polish study by Rydzewska et al.,6 only 21.97% were aware of the concept. It should be noted that in studies conducted across all the academic years, such as the Spanish one,2,3 the level of knowledge improves as the students advance. Only 51% of first-year students were aware that BD means the person has died, a lower rate than that reported for the population as a whole.4 However, understanding improves over time and 89% of students in year 6th knew the concept. It is clear that information on the subject and clinical experience are factors that facilitate knowledge about and acceptance of the concept.
As shown in Table 1, there are very few studies that have analysed knowledge of the concept of BD among students, and the data they present is confounding. Meta-analytical techniques may be interesting in such situations, as they contribute to the synthesis of existing data and help establish conclusions. In this case, the lack of association between knowledge about the concept of BD among medical students and their attitude towards organ donation was striking.
