Effect of waivers of consent on recruitment in acute stroke trials: A systematic review

Protocol for Deferral of Consent in Acute Stroke Trials

The challenges of conducting hyperacute stroke research and obtaining informed consent have been increasingly recognized within the stroke research community in recent years. Deferral of consent, in which a patient is enrolled in a trial and then provides consent at some point thereafter, is increasingly used to enroll patients into hyperacute stroke trials in Canada and Europe, although it is not permitted in the United States. Deferral of consent offers several potential advantages-quicker door-to-randomization, increased enrolment, decreased selection bias-but these must be balanced against the risk of enrolling patients against their wishes. We seek to minimize the attendant risks of deferral of consent by offering practical guidance regarding how to conduct acute stroke trials using deferral of consent. Building on existing guidelines and recent experiences with deferral of consent in acute stroke trials, we have developed a protocol for the use of deferral of consent that aims to maximize patient involvement while minimizing ethical and scientific risks.

Reporting of and explanations for under-recruitment and over-recruitment in pragmatic trials: a secondary analysis of a database of primary trial reports published from 2014 to 2019

OBJECTIVES

To describe the extent to which pragmatic trials underachieved or overachieved their target sample sizes, examine explanations and identify characteristics associated with under-recruitment and over-recruitment.

STUDY DESIGN AND SETTING

Secondary analysis of an existing database of primary trial reports published during 2014-2019, registered in ClinicalTrials.gov, self-labelled as pragmatic and with target and achieved sample sizes available.

RESULTS

Of 372 eligible trials, the prevalence of under-recruitment (achieving <90% of target sample size) was 71 (19.1%) and of over-recruitment (>110% of target) was 87 (23.4%). Under-recruiting trials commonly acknowledged that they did not achieve their targets (51, 71.8%), with the majority providing an explanation, but only 11 (12.6%) over-recruiting trials acknowledged recruitment excess. The prevalence of under-recruitment in individually randomised versus cluster randomised trials was 41 (17.0%) and 30 (22.9%), respectively; prevalence of over-recruitment was 39 (16.2%) vs 48 (36.7%), respectively. Overall, 101 025 participants were recruited to trials that did not achieve at least 90% of their target sample size. When considering trials with over-recruitment, the total number of participants recruited in excess of the target was a median (Q1-Q3) 319 (75-1478) per trial for an overall total of 555 309 more participants than targeted. In multinomial logistic regression, cluster randomisation and lower journal impact factor were significantly associated with both under-recruitment and over-recruitment, while using exclusively routinely collected data and educational/behavioural interventions were significantly associated with over-recruitment; we were unable to detect significant associations with obtaining consent, publication year, country of recruitment or public engagement.

CONCLUSIONS

A clear explanation for under-recruitment or over-recruitment in pragmatic trials should be provided to encourage transparency in research, and to inform recruitment to future trials with comparable designs. The issues and ethical implications of over-recruitment should be more widely recognised by trialists, particularly when designing cluster randomised trials.

Ethical Considerations during the Informed Consent Process for Acute Ischemic Stroke in International Clinical Trials

We sought to investigate the experiences of researchers in existing active-control trials in acute ischemic stroke comparing investigational therapy to tissue plasminogen activator (tPA) in order to identify the approaches and challenges in obtaining informed consent. Out of 401 articles evaluated, 14 trials met inclusion criteria. Trial representatives were contacted to complete a survey concerning the consent process. None of the 14 trials published materials related to the informed consent process. Trials with 75% to 100% of patients directly consented had shorter door-to-treatment (DTT) times than trials that directly consented less than 50% of patients. Trials that had translators available (for recruiting participants who were not native speakers in the local language) and translated consent documents had longer DTT times. The study findings suggest that differences in the standards of informed consent internationally may allow more patients with moderate strokes to provide direct consent without delaying DTT time. Future trials should emphasize transparency to the public and scientific community in the informed consent process.

Ethical Justification for Deferral of Consent in the AcT Trial for Acute Ischemic Stroke

The AcT trial (Alteplase Compared to Tenecteplase) compares alteplase or tenecteplase for patients with acute ischemic stroke. All eligible patients are enrolled by deferral of consent. Although the use of deferral of consent in the AcT trial meets the requirements of Canadian policy, we sought to provide a more explicit and rigorous approach to the justification of deferral of consent organized around 3 questions. Ultimately, the approach we outline here could become the foundation for a general justification for deferral of consent.

Practicalities of Impracticability: An Interim Review of Randomized Controlled Trials

Impracticability is an ethical standard for waiver of informed consent in research. We examine how well the criterion of impracticability appears to have been fulfilled in a set of 36 completed randomized controlled trials (RCTs) that secured consent from some subjects or LARs and employed waivers to enroll others. These trials were identified among 155 RCTs using waivers of consent in a convenience sample drawn from 7 systematic reviews. Recruitment data were available for 19 of the 36 trials, revealing an average of 41.6% of subjects (range 0.2-98.7%, 95% CI: 24.8-58.4%) were enrolled without consent. Six trials enrolled less than 10% of subjects without consent and an overlapping set of 9 trials sought consent from all subjects or LARs at some sites while waiving consent at other sites. We question whether these trials were practicable without waivers and identify issues for consideration by investigators and ethics review boards.

Consent Issues in the Management of Acute Ischemic Stroke

This position statement briefly reviews the principle of informed consent, the elements of decisional capacity, and how acute stroke may affect this capacity. It further reviews the role of surrogate decision-making, including advance directives, next of kin, physician orders for life-sustaining treatment, and guardianship. In some cases of acute stroke in which the patient lacks decisional capacity and no advance directives or surrogates are available, consent to treatment may be presumed. The document describes the rationale for this position and various considerations regarding its application to IV thrombolysis, neuroendovascular intervention, decompressive craniectomy, and pediatric stroke. The document also reviews consent issues in acute stroke research.

Using the Barthel Index and modified Rankin Scale as Outcome Measures for Stroke Rehabilitation Trials; A Comparison of Minimum Sample Size Requirements

OBJECTIVES

Underpowered trials risk inaccurate results. Recruitment to stroke rehabilitation randomised controlled trials (RCTs) is often a challenge. Statistical simulations offer an important opportunity to explore the adequacy of sample sizes in the context of specific outcome measures. We aimed to examine and compare the adequacy of stroke rehabilitation RCT sample sizes using the Barthel Index (BI) or modified Rankin Scale (mRS) as primary outcomes.

METHODS

We conducted computer simulations using typical experimental event rates (EER) and control event rates (CER) based on individual participant data (IPD) from stroke rehabilitation RCTs. Event rates are the proportion of participants who experienced clinically relevant improvements in the RCT experimental and control groups. We examined minimum sample size requirements and estimated the number of participants required to achieve a number needed to treat within clinically acceptable boundaries for the BI and mRS.

RESULTS

We secured 2350 IPD (18 RCTs). For a 90% chance of statistical accuracy on the BI a rehabilitation RCT would require 273 participants per randomised group. Accurate interpretation of effect sizes would require 1000s of participants per group. Simulations for the mRS were not possible as a clinically relevant improvement was not detected when using this outcome measure.

CONCLUSIONS

Stroke rehabilitation RCTs with large sample sizes are required for accurate interpretation of effect sizes based on the BI. The mRS lacked sensitivity to detect change and thus may be unsuitable as a primary outcome in stroke rehabilitation trials.

Deferred Consent in an Acute Stroke Trial from a Patient, Proxy, and Physician Perspective: A Cross-Sectional Survey

Background

In some acute care trials, immediate informed consent is not possible, but deferred consent is often considered problematic. We investigated the opinions of patients, proxies, and physicians about deferred consent in an acute stroke trial to gain insight into its acceptability and effects.

Methods

Paper-based surveys were sent to patients who were randomly assigned in the Ultra-early Tranexamic Acid After Subarachnoid Hemorrhage (ULTRA) trial between 2015 and 2018 in two tertiary referral centers and to physicians of centers who agreed or declined to participate. The primary outcome measure was the proportion of respondents who agreed with deferral of consent in the ULTRA trial. Secondary outcomes included respondents’ preferred consent procedure for the ULTRA trial, the effect of deferred consent on trust in physicians and scientific research, and the willingness to participate in future research.

Results

Eighty-nine of 135 (66%) patients or proxies and 20 of 30 (67%) physicians completed the survey. Of these, 82 of 89 (92%) patients or proxies and 14 of 20 (70%) physicians agreed with deferral of consent in the ULTRA trial. When asked for their preferred consent procedure for the ULTRA trial, 31 of 89 (35%) patients or proxies indicated deferred consent, 15 of 89 (17%) preferred immediate informed consent, and 32 of 89 (36%) had no preference. None of the patients’ or proxies’ trust in physicians or scientific research had decreased because of the deferred consent procedure. Willingness to participate in future studies remained the same or increased in 84 of 89 (94%) patients or proxies.

Conclusions

A large majority of the surveyed patients and proxies and a somewhat smaller majority of the surveyed physicians agreed with deferred consent in the ULTRA trial. Deferred consent may enable acute care trials in an acceptable manner without decreasing trust in medicine. Future research should investigate factors facilitating the responsible use of deferred consent, such as in-depth interviews, to study the minority of participants who agreed with deferred consent but still preferred immediate informed consent.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01357-3.

Refusal rates and waivers of informed consent in pragmatic and comparative effectiveness RCTs: A systematic review

BACKGROUND

Pragmatic and comparative effectiveness randomized controlled trials (RCTs) aim to be highly generalizable studies, with broad applicability and flexibility in methods. These trials also address recruitment issues by minimizing exclusions. The trials may also appeal to potential subjects because of lower risk and lower burdens of participation. We sought to examine rates of refusal and uses of waivers of informed consent in pragmatic and comparative effectiveness RCTs.

METHODS

A systematic review of pragmatic and comparative effectiveness RCTs performed wholely or in part in the United States and first published in 2014 and 2017.

RESULTS

103 studies involving 105 discrete populations were included for review. Refusal data was collected for 71 RCTs. Overall, studies reported an average rate of 31.9% of potential subjects refused participation; on an individual basis, 38.4% of people asked to take part refused at some point during recruitment. 23 trials (22%) were performed, at least in part, with a waiver of informed consent, 7 (30%) of which provided any form of notice to subjects.

CONCLUSIONS

Overall refusal rates for pragmatic and comparative effectiveness RCTs appear roughly the same as other types of research, with studies reporting about a third of people solicited for participation refuse. Moreover, informed consent was waived in 22% (95% Binomial exact Confidence Interval 13.9-30.5%) of the trials, and further study is needed to understand when waivers are justified and when notice should be provided.

High-impact RCTs without prospective informed consent: a systematic review

The prevalence of randomized controlled trials (RCTs) performed without fully informed prospective consent from subjects is unknown. We performed this study to estimate the prevalence of high-impact RCTs performed without informed consent from all subjects and examine whether such trials are becoming more prevalent. We performed a systematic review of English-language RCTs published from 2014 through 2018 identified in Scopus and sorted to identify the top 100 most highly cited RCTs each year. Text search of title and abstract included terms randomized controlled or clinical trial and spelling variants thereof, and excluded metaanalyses and systematic reviews. We independently identified the most highly cited RCTs based on predefined criteria and negotiated to agreement, then independently performed keyword searches, read, abstracted and coded information regarding informed consent from each paper and again negotiated to agreement. No quality indicators were assessed. We planned descriptive qualitative analysis and appropriate quantitative analysis to examine the prevalence and characteristics of trials enrolling subjects with other than fully informed prospective consent. We find that 44 (8.8%, binomial exact 95% CI 6.5% to 11.6%) of 500 high-impact RCTs did not secure informed consent from at least some subjects. The prevalence of such trials did not change over the 5 years (OR=1.09, z=0.78, p=0.44). A majority (66%) of the trials involved emergency situations, and 40 of 44 (90.9%) of the trials involved emergency interventions, pragmatic designs, were cluster randomized, or a combination of these factors. A qualitative analysis explores the methods of and justifications for waiving informed consent in our sample of RCTs.

Recruitment challenges in stroke rehabilitation randomized controlled trials: a qualitative exploration of trialists' perspectives using Framework analysis

OBJECTIVE

To explore the underlying reasons for recruitment difficulties to stroke rehabilitation randomized controlled trials from the perspective of trialists.

DESIGN

A qualitative study using semi-structured interviews and Framework analysis.

PARTICIPANTS

Twenty multidisciplinary stroke rehabilitation trialists across 13 countries with a range of clinical and research experience.

METHODS

Twenty semi-structured telephone interviews were carried out. Purposeful sampling ensured a range of opinions were gathered from across the international stroke rehabilitation research community. Using Framework analysis, the analytical framework was formed by three researchers and tested before being applied to the total dataset.

RESULTS

Three themes described the trialists' perception of the underlying reasons for recruitment difficulties: (i) decision making, (ii) importance of recruiters and (iii) a broken system. Trialists described frequently disregarding evidence in favour of prior research experiences when planning randomized controlled trial recruitment. All felt that the relationship between the research and clinical teams was vital to ensure recruiters prioritized and found value in recruitment to the trial. Experienced trialists were frustrated by the lack of reporting of the reality of running trials, research governance demands and the feeling that they had to deliberately underestimate recruitment timeframes to secure funding.

CONCLUSION

Stroke rehabilitation trialists described recruitment difficulties which may be related to their experiential based recruitment decision making, a lack of understanding of how best to incentivize and maintain relationships with recruiters and unrealistic bureaucratic expectations both in terms of gaining funding and research governance.

A systematic review of the efficiency of recruitment to stroke rehabilitation randomised controlled trials

INTRODUCTION

Randomised controlled trials (RCTs) that fail to meet their recruitment target risk increasing research waste. Acute stroke RCTs experience notable recruitment issues. The efficiency of recruitment to stroke rehabilitation RCTs has not been explored.

AIMS AND OBJECTIVES

To explore recruitment efficiency and the trial features associated with efficient recruitment to stroke rehabilitation RCTs.

METHODS

A systematic review of stroke rehabilitation RCTs published between 2005 and 2015 identified in a search of the Cochrane Stroke Group (CSG) Trials Register from 35 electronic databases (e.g. Medline, CINAHL; EMBASE), clinical trial registers, and hand-searching. Inclusion criteria are stroke rehabilitation intervention, delivered by a member of the rehabilitation team, and clinically relevant environment. We extracted data on recruitment efficiency and trial features.

RESULTS

We screened 12,939 titles, 1270 abstracts and 788 full texts, before extracting data from 512 included RCTs (n = 28,804 stroke survivor participants). This is the largest systematic review of recruitment to date. A third of stroke survivors screened consented to participate (median 34% (IQR 14-61), on average sites recruited 1.5 participants per site per month (IQR 0.71-3.22), and one in twenty (6% (IQR 0-13) dropped out during the RCT. Almost half (48%) of those screened in the community were recruited compared to hospital settings (27%). Similarly, almost half (47%) those screened at least 6 months after stroke participated, compared to 23% of stroke survivors screened within a month of stroke. When one recruiter screened multiple sites, a median of one stroke survivor was recruited every 2 months compared to more than two per month when there was a dedicated recruiter per site. RCT recruitment was significantly faster per site, with fewer dropouts, for trials conducted in Asia (almost three stroke survivors monthly; 2% dropout) compared to European trials (approximately one stroke survivor monthly; 7% dropout).

CONCLUSIONS

One third of stroke survivors screened were randomised to rehabilitation RCTs at a rate of between one and two per month, per site. One in twenty did not complete the trial. Our findings will inform recruitment plans of future stroke rehabilitation RCTs. Limited reporting of recruitment details restricted the subgroup analysis performed.

TRIAL REGISTRATION

Prospective Register of Systematic Reviews, registration number CRD42016033067.

Deferral of Consent in Acute Stroke Trials

Background and Purpose—

The ESCAPE trial (The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times) was a multicentre, randomized controlled trial of endovascular thrombectomy versus standard care for patients with acute ischemic stroke that allowed patients to be enrolled with deferred consent. We investigated the knowledge and opinions of these patients or their authorized third parties about the consent process.

Methods—

All patients (or their authorized third parties) enrolled with deferral of consent in ESCAPE were invited to complete a 12-question survey within the first 4 days of enrollment and again at 90 days. Questions investigated knowledge of the ESCAPE trial and opinions on deferral of consent.

Results—

Of 56 patients enrolled with deferred consent, 33 (59%) completed the initial survey, and of these, 27 (81%) completed the 90-day follow-up. Enrollment with deferred consent was not associated with a significant difference in door-to-randomization times (50.5 versus 57 minutes; P =0.29) but allowed these 56 patients to participate in the trial. Only 52% of respondents understood that patients could be randomized to thrombectomy or standard care, although most understood the other basic principles of the trial. At baseline and at 90 days, respondents disagreed or strongly disagreed with deferred consent in acute stroke trials generally (82% and 78%) and in the ESCAPE trial specifically (93% and 91%).

Conclusions—

Respondents generally disagreed with the use of deferred consent for enrollment in the ESCAPE trial and in stroke trials more generally.

Characteristics of the shoulder in patients following acute stroke: a case series

BACKGROUND

Stroke can result in pain and loss of motor control in the hemiplegic shoulder, and while prevention of secondary changes is likely to be the most effective management, there is limited evidence directing clinicians towards the most at-risk patients.

OBJECTIVES

The aim of this case series was to investigate the presentation of shoulder pain, motor impairment, shoulder passive range of motion (PROM) and alignment of the hemiplegic shoulder following acute stroke.

METHODS

This study reported data that was collected as part of a pilot randomized controlled trial investigating kinesiology taping of the hemiplegic shoulder. Participants with a diagnosis of acute stroke and severe upper limb motor impairment were included. From 24-h post stroke and continuing every three days until discharge, measurements of shoulder pain (visual analogue scale, Ritchie Articular Index), motor impairment (Chedoke McMaster Stroke Assessment), PROM and alignment (both clinical measures) were collected. Clinical trial registry number - ACTRN12615000502538.

RESULTS

Of 156 patients screened over six months, 10 of 15 eligible participants were recruited. On initial assessment, three participants reported pain and all had severe upper limb motor impairment. All participants initially demonstrated close to full shoulder PROM. Six participants had shoulder subluxation and five demonstrated scapula malalignment.

CONCLUSIONS

Given the severity of upper limb motor impairment, pain and reduced PROM were seen in a small number of participants. The clinical course of shoulder pain and PROM following stroke remains unclear. Large observational studies tracking shoulder characteristics from acute through to rehabilitation settings are needed.

Trends in Recruitment Rates for Acute Stroke Trials, 1990-2014

BACKGROUND AND PURPOSE

Slow recruitment in acute stroke trials hampers the evaluation of new therapies and delays the adoption of effective therapies into clinical practice. This systematic review evaluates whether recruitment efficiency and rates have increased in acute stroke trials from 1990 to 2014.

METHODS

Acute stroke trials from 2010 to 2014 were identified by a search of PubMed, Medline, the Cochrane Database of Research in Stroke, and the Stroke Trials Registry. These trials were compared to a previously published data set of trials conducted from 1990 to 2004.

RESULTS

The median recruitment efficiency of trials from 1990 to 2004 was 0.41 participants/site/month compared with 0.26 participants/site/month from 2010 to 2014 (P=0.14). The median recruitment rate of trials from 1990 to 2004 was 26.8 participants/month compared with 19.0 participants/month from 2010 to 2014 (P=0.13).

CONCLUSIONS

For acute stroke trials, neither recruitment efficiency nor recruitment rates have increased over the past 25 years and, if anything, have declined.