Impact of selection criteria on recruitment in an interventional stroke trial

Follow-up of Patients With Stroke, Based on Opt-Out Choice Potential Approach for Acute Care Quality Registries or Observational Studies

BACKGROUND AND OBJECTIVES

Restricting follow-up assessment of both interventional and observational studies to patients who provide informed consent introduces relevant selection bias - particularly by underrepresenting patients with neurological communication deficits and impaired capacity to consent. Many patients who are initially unable to give consent may be willing to do so after recovery. Informing patients on study purposes and procedures with offering them the option of non-participation but not requesting explicit consent is called 'opt-out' approach. We investigated whether an opt-out strategy yields meaningful follow-up rates in an acute stroke registry with embedded controlled study.

METHODS

The citywide Berlin-Specific Acute Treatment in Ischemic or hAemorrhagic stroke with Long-term follow-up (B_SPATiAL) registry was designed to provide reliable information on process indicators and outcomes of specific acute stroke treatments in order to inform health care providers about quality of care and best-practice strategies including the effects of a Mobile Stroke Unit implementation. Because this information was regarded of high public interest, Berlin data protection authorities permitted data sampling without prior informed consent, employing instead follow-up assessment on "opt-out" basis. Patients were included if they had neurological symptoms at ambulance or hospital arrival within 6h of onset and had a final diagnosis of stroke or TIA. Information on data collection and outcome assessment was sent by letter to patients one month before follow-up.

RESULTS

From 1^st Feb 2017 to 31^st Jan 2020, a total of 10,597 patients were assessed. Thirty-one (0.3%) patients declined any data use, while 578 (5.5%) opted out of follow-up assessment. Of those not opting-out (n=9,988), functional outcome (modified Rankin Scale) was collected in 8,330 patients (83.4%) and vital status in 9,741 patients (97.5%). We received no complaints regarding data collection procedures.

DISCUSSION

Opt-out based follow-up collection offers a way to achieve high follow-up rates along with respecting patients' preferences.

Recruitment challenges in stroke neurorecovery clinical trials

There are multiple available treatments to enhance stroke rehabilitation, although few interventions have confirmed significant clinical improvements on motor function in pivotal Randomized Clinical Trials. Development of large Randomized Clinical Trials is limited by several barriers and low enrollment rate is considered an important factor. Consequently, most of the evidence comes from small sample size studies, often leading to limited conclusions. According to the National Institute of Health (NIH), about 80% of clinical trials in the United States do not achieve their timelines, increasing research costs and postponing regulatory approval of new therapies. Given that the success of a Randomized Clinical Trial is dependent on enrolling an adequate number of subjects, effective strategies to enhance recruitment rates are highly desirable. In addition, given the resources and time limitations, it is important to understand which strategies are most cost-effective. In this manuscript, we summarize and discuss nine recruitment strategies used in an NIH R21 sponsored clinical trial, including medical records review and online advertising, among others. In addition, we developed an index to compare the time spent benefit of each approach and guide the allocation of the recruitment efforts. For this trial, online advertising and referral from health care professionals other than physicians were the strategies with greater time-benefit, leading to the largest number of stroke subjects enrolled.

Selection bias in clinical stroke trials depending on ability to consent

Background

Clinical trials are the hallmark of evidence-based medicine, but recruitment is often challenging, especially in stroke trials investigating patients not being able to give informed consent. In some nations, ethics committees will not approve of inclusion in a clinical study via consent of a legal representative. The ethical dilemma of including or excluding those patients has not been properly addressed, as there is little data on the effect of stroke characteristics on the ability to give informed consent.

Methods

To examine differences between patients able and unable to consent at inclusion to an acute stroke trial, we conducted a post-hoc analysis of monitoring records from a multicentric interventional trial. These records listed patients who gave informed consent by themselves and those who needed a legal representative to do so. This exemplary STRAWINSKI trial aimed at improving stroke outcome by biomarker-guided antibiotic treatment of stroke associated pneumonia and included patients within 40 h after stroke onset, suffering from MCA infarctions with an NIHSS score > 9 at admission. Standard descriptive and associative statistics were calculated to compare baseline characteristics and outcome measures between patients who were able to consent and those who were not.

Results

We identified the person giving consent in 228 out of 229 subjects. Patients with inability to consent were older (p < 0.01), suffered from more left-hemispheric (p < 0.01) and more severe strokes (NIHSS, p < 0.01), were more likely to die during hospitalisation (p < 0.01) or have unfavourable outcome at discharge (mRS, p < 0.01), to develop fever (p < 0.01) and tended to be more susceptible to infections (p = 0.06) during the acute course of the disorder.

Conclusions

Demographics, stroke characteristics and outcomes significantly affect stroke patients in their ability to consent. Where selection criteria and primary outcome measures of a trial are significantly affected by ability to consent, excluding patients unable to consent might be unethical.

Trial registration

URL http://www.clinicaltrials.gov. Unique identifier: NCT01264549.

Electronic supplementary material

The online version of this article (10.1186/s12883-017-0989-9) contains supplementary material, which is available to authorized users.

Recruiting a representative sample in adherence research-The MALT multisite prospective cohort study experience

Medication adherence is an important determinant of transplant outcomes. Attempts to investigate adherence are frequently undermined by selection bias: It is very hard to recruit and retain non-adherent patients in research efforts. This manuscript presents recruitment strategies and results from the MALT (Medication Adherence in children who had a Liver Transplant) multisite prospective cohort study. MALT sites recruited 400 pediatric liver transplant patients who agreed to be followed for 2 years. The primary purpose was to determine whether a marker of adherence, the Medication Level Variability Index (MLVI), predicts rejection outcomes. The present manuscript describes methods used in MALT to ensure that a representative sample was recruited, and presents detailed recruitment results. MALT sites were able to recruit a nationally representative sample, as determined by a comparison between the MALT cohort and a national sample of transplant recipients. Strategies that helped ensure that the sample was representative included monitoring of the outcome measure in comparison with a national sample, drastically limiting patient burden, and specific recruitment methods. We discuss the importance of a representative sample in adherence research and recommend that future efforts to study adherence pay special attention to sample characteristics.

Effect of informed consent on patient characteristics in a stroke thrombolysis trial

OBJECTIVE

To determine whether the manner of consent, i.e., informed consent by patients themselves or informed consent by proxy, affects clinical characteristics of samples of acute stroke patients enrolled in clinical trials.

METHODS

We analyzed the manner of obtaining informed consent in the first 1,005 patients from WAKE-UP, an investigator-initiated, randomized, placebo-controlled trial of MRI-based thrombolysis in stroke patients with unknown time of symptom onset running in 6 European countries. Patients providing informed consent by themselves were compared with patients enrolled by proxy consent. Baseline clinical measures were compared between groups.

RESULTS

In 359 (35.7%) patients, informed consent was by proxy. Patients with proxy consent were older (median 71 vs 66 years, p < 0.0001) and had a higher frequency of arterial hypertension (58.2% vs 43.4%, p < 0.0001). They showed higher scores on the NIH Stroke Scale (median 11 vs 5, p < 0.0001) and more frequently aphasia (73.7% vs 20.0%, p < 0.0001). The rate of proxy consent varied among countries (p < 0.0001), ranging from 77.1% in Spain to 1.2% in Denmark.

CONCLUSIONS

Patients recruited by proxy consent were older, had more severe strokes, and had higher prevalence of aphasia than those with capacity to give personal consent. Variations in the manner of consent across countries may influence trial results.

CLINICALTRIALSGOV AND CLINICALTRIALSREGISTEREU IDENTIFIERS

NCT01525290 (clinicaltrials.gov); 2011-005906-32 (clinicaltrialsregister.eu).