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The effect on consent rates for deceased organ donation in Wales after the introduction of an opt‐out system

Summary Organ transplantation saves and transforms lives. Failure to secure consent for organ retrieval is widely regarded as the single most important obstacle to transplantation. A soft opt‐out system of consent for deceased organ donation was introduced into Wales in December 2015, whilst England maintained the existing opt‐in system. Cumulative data on consent rates in Wales were compared with those in England, using a two‐sided sequential procedure that was powered to detect an absolute difference in consent rates between England and Wales of 10%. Supplementary risk‐adjusted logistic regression analysis examined whether any difference in consent rates between the two nations could be attributed to variations in factors known to influence UK consent rates. Between 1 January 2016 and 31 December 2018, 8192 families of eligible donors in England and 474 in Wales were approached regarding organ donation, with overall consent rates of 65% and 68%, respectively. There was a steady upward trend in the proportion of families consenting to donation after brain death in Wales as compared with England and after 33 months, this reached statistical significance. No evidence of any change in the donation after circulatory death consent rate was observed. Risk‐adjusted logistic regression analysis revealed that by the end of the study period the probability of consent to organ donation in Wales was higher than in England (OR [95%CI] 2.1 [1.26–3.41]). The introduction of a soft opt‐out system of consent in Wales significantly increased organ donation consent though the impact was not immediate.


Introduction
Organ transplantation saves and transforms lives, and economic analysis suggests it saves the NHS hundreds of millions of pounds each year [1]. Access to solid organ transplantation is determined by donor and donor organ availability, and whilst the identification and referral of potential deceased donors often restricts organ availability, failure to secure consent for organ retrieval is regarded widely as the single most important obstacle to transplantation [1].
The legal frameworks for consent for deceased organ donation fall into two major categories: opt-in, where expressed consent is required from the patient or their relatives; and opt-out, where consent is presumed in the absence of a statement made by the patient in their lifetime to the contrary. Most of the studies exploring models of organ donation consent have been retrospective and observational, usually involving either a direct comparison between different jurisdictions or, less commonly, 'before and after' studies of the impact of switching from opt-in to an opt-out system of consent within a given country [2][3][4][5][6][7].
The UK is made up of four major nations: England (population 56.0 million); Scotland (population 5.4 million); Wales (population 3.1 million); and Northern Ireland (population 1.9 million) [8]. Although responsibility for healthcare is devolved to each nation to organise and deliver, organ donation is delivered nationally by NHS Blood and Transplant as single UK-wide service. This organisation is responsible for all key elements of the donation pathway in the UK, namely: donor identification and referral; family approach for consent; and organ retrieval. to support the deemed consent, a system known as soft opt-out. As in England, there is no legal right to veto an expressed positive decision to donate; however, in practical terms this can still happen. The same is true of overriding a deemed consent in Wales, where opposition from a family will stop donation proceeding.
The methodology of our study was designed to take advantage of the unique opportunity to prospectively compare consent rates for deceased donation in Wales with those in England, in order to investigate the impact of the change in legislation.

Methods
The majority of data analysed in this study are from the UK Potential Donor Audit, a continuous national audit of all patients aged ≤ 80 years who die within an intensive care unit or emergency department in a UK hospital [10]. The were 67% for DBD and 53% for DCD. Underlying DBD and DCD consent rates between the two nations were assumed to be the same before the change in legislation. Before deemed consent commenced in Wales, a decision was made to only compare Wales with England, as Scotland had publicly announced plans to explore moving to an opt-out system, and this may have impacted on consent rates.
Analyses were performed using a two-sided sequential procedure [11,12], designed to have 90% power to detect an absolute difference in consent rates between England and Wales of 10%, with significance at the 5% level. With a standard fixed sample test of two proportions we would expect to wait 5 years before completing sample recruitment. For this reason, a sequential study design was used so that data could be legitimately reviewed on a regular basis. By using O'Brien and Fleming boundaries, more stringent significance levels were utilised in the earlier assessments [13]. This study design would also account for the fact that the number of eligible deceased donors in England was approximately 20 times that of Wales. Expected sample sizes were such that the duration of the study would be around 3 years (12 quarters) if there was a true difference in consent rates. Using this sequential study design, cumulative data on consent rates in Wales were compared with those in England, and the quarterly results were shared over the life of the study with the Welsh government and interested stakeholders.
Once unadjusted sequential analyses were complete, retrospective risk-adjusted logistic regression analysis was conducted [14], to further examine the impact of opt-out on consent rates once the effect of other factors known to influence UK consent rates had been taken into account [15]. At the end of each quarter, the significance of the difference in the cumulative proportions was evaluated using a z-statistic for comparing the two proportions [11].
The quarterly values of the z-statistic were plotted against the number of eligible donors whose families were  Table 1. There was considerable variation in the quarterly consent rates in Wales, which can be attributed to the much smaller number of potential donors in Wales compared with England. Nevertheless, it can be seen that quarterly DBD consent rates in Wales were generally higher than in England. In contrast, whilst DCD consent rates in Wales were initially much lower, they gradually increased and eventually were higher than in England. English DCD consent rates remained relatively static throughout.
The corresponding sequential charts for DBD and DCD donors with quarterly values of the z-statistic plotted against number of families approached are shown in Fig. 1. As the quarterly monitoring progressed, a steady upward trend was observed in the sequential chart (Fig. 1a) showing an improving DBD consent rate in Wales relative to England. In quarter 11, the plotted point crossed the upper boundary concluding the DBD study and providing statistical evidence of a significant increase in the DBD consent rate in Wales compared with England. Data for quarter 12 continued the improving trend and an additional test was well within the boundary, verifying our findings. The sequential chart provided no evidence of a similar trend in DCD consent rates (Fig 1b). Although an improving DCD trend can be observed in the latter quarters (and Table 1 gives the appearance of dramatic improvement in the last three quarters) the study concluded with the plotted points for DCD consent crossing the dotted line at the end of sample recruitment. This unadjusted analysis shows that there was no evidence of any statistical change in the DCD Table 1 Quarterly rates of organ donation after diagnosis of death using neurological criteria (donation after brain death) and controlled donation after circulatory death for England and Wales from 1 January 2016 to 31 December 2018. Values are number and proportion. evidence to support that the potential donor had changed their mind and the registered opt-out was not the last known decision, the registered opt-out could be overridden. This never occurred during the study period.
Our sequential analysis identified a significant increase in terms of the Welsh DBD consent rates relative to the rate in England. This evidence was not replicated in the same quarterly DCD consent rate monitoring. We speculate that DCD was less influenced by the legislation change than DBD due to differing family experiences of the two types of donation [21][22][23].
The supplementary multivariable logistic regression analysis provided additional evidence of a significant difference in combined DBD and DCD consent rates between the two nations over and above the effect of previous published key influential factors. Our analysis showed that there was a delay of 2 years from the introduction of the opt-out policy before the difference in consent rates became apparent for combined DBD and DCD donation in Wales. This finding was supported by an earlier study which showed no difference in consent rates for organ donation between Wales and the rest of the UK in the first 18 months following implementation of the new legislation [24].
A key limitation in our analysis was that the sequential analysis assumed the underlying Welsh and England consent rates were similar before opt-out and that the impact would be immediate. We only compared Wales to England and did not include Scotland or Northern Ireland but as their population numbers are relatively small compared with England, we do not believe this would have impacted upon our findings.
The Welsh example has been observed closely by other nations. In 2019, both England and Scotland passed legislation to introduce deemed consent and deemed authorisation respectively. While in Nova Scotia and the Netherlands, authorities have also introduced opt-out legislation. We would urge all countries contemplating a change to their consent legislation, or another major initiative to increase organ donation numbers, to consider and design before implementation how they will assess the impact of any changes.
The introduction of an opt-out policy for organ donation in Wales provided a unique opportunity to compare consent rates for deceased donation in Wales with England prospectively. We observed that organ donation consent rates in Wales significantly increased in comparison with England, although the impact was not immediate and took several years to take effect. Our study and the experience from Wales provides evidence to inform and support opt-out initiatives world-wide which, if replicated, could increase consent rates and consequently improve the number of organs available for transplant.