Physicians declining patient enrollment in clinical trials: what are the implications?

Recruitment characteristics of randomised trials in critical care: A systematic review

BACKGROUND/AIMS

To summarise the temporal trends of recruitment and methodological characteristics of critical care randomised controlled trials with the primary outcome of mortality.

METHODS

PubMed was searched for articles meeting inclusion and exclusion criteria. Randomised controlled trials, with primary outcome of mortality, of adult and paediatric critical care patients treated in an intensive care unit, were included. Neonatal intensive care unit trials, non-English publications and conference proceedings or abstracts without full-length publications were excluded. Duplicate literature search, article selection and quality assessment were performed by two reviewers with disputes resolved through discussion. Data were extracted into a custom-designed Research Electronic Data Capture database.

RESULTS

The search identified 67,199 records of which 230 were included. The annual number of critical care randomised controlled trials published increased gradually over a 30-year period from 0 in 1990 to 19 in 2014 with stabilisation at 8-11 between 2015 and 2020. Twenty-seven percent of randomised controlled trials were low risk in all categories using the Cochrane Risk of Bias tool. Methodological characteristics such as registration on clinical trials registries and data safety monitoring committee presence significantly (p < 0.001) increased over time. The median recruitment was 376 patients (interquartile range 125-895) with significant increase (p = 0.002) from 62 (interquartile range: 33-486) in 1991 to 725 (interquartile range: 537-2600) in 2020. This was accompanied by an increase in recruitment times. Thus overall, recruitment rates did not increase. Early cessation occurred in 23% (54/230) of randomised controlled trials with no temporal trend.

CONCLUSION

The number, size and some methodological qualities of critical randomised controlled trials with primary outcome of mortality have increased over time, but rates of recruitment and early cessation have been unchanged.

Applicability of Vasopressor Trials in Adult Critical Care: A Prospective Multicentre Meta-Epidemiologic Cohort Study

Objective

To assess the applicability of evidence from landmark randomized controlled trials (RCTs) of vasopressor treatment in critically ill adults.

Study Design and Setting

This prospective, multi-center cohort study was conducted at five medical and surgical intensive care units at three tertiary care centers. Consecutive cases of newly initiated vasopressor treatment were included. The primary end point was the proportion of patients (≥18 years) who met the eligibility criteria of 25 RCTs of vasopressor therapy in critically ill adults included in the most recent Cochrane review. Multilevel Poisson regression was used to estimate the eligibility proportions with 95% confidence intervals for each trial. Secondary end points included the eligibility criteria that contributed most to trial ineligibility, and the relationship between eligibility proportions and (i) the Pragmatic-Explanatory Continuum Indicator Summary-2 (PRECIS-2) score, and (ii) the recruitment-to-screening ratio of each RCT. The PRECIS-2 score was used to assess the degree of pragmatism of each trial.

Results

Between January 1, 2017, and January 1, 2019, a total of 1189 cases of newly initiated vasopressor therapy were included. The median proportion of cases meeting eligibility criteria for all 25 RCTs ranged from 1.3% to 6.0%. The eligibility criteria contributing most to trial ineligibility were the exceedance of a specific norepinephrine dose, the presence of a particular shock type, and the drop below a particular blood pressure value. Eligibility proportions increased with the PRECIS-2 score but not with the recruitment-to-screening ratio of the trials.

Conclusion

The applicability of evidence from available trials on vasopressor treatment in critically ill adults to patients receiving vasopressors in daily practice is limited. Applicability increases with the degree of study pragmatism but is not reflected in a high recruitment-to-screening ratio. Our findings may help researchers design vasopressor trials and promote standardized assessment and reporting of the degree of pragmatism achieved.

An evaluation of factors that may influence clinicians' decisions not to enroll eligible patients into randomized trials in critical care

OBJECTIVES

To determine the association between intensive care unit (ICU) characteristics and clinicians' decision to decline eligible patients for randomization into a multicentered pragmatic comparative-effectiveness controlled trial.

METHODS

Screening logs from the Adjunctive Glucocorticoid Therapy in Septic Shock Trial (ADRENAL) and site-level data from the College of Intensive Care Medicine and Australia New Zealand Intensive Care Society were examined. The effects of ICU characteristics such as tertiary academic status, research coordinator availability, number of admissions, and ICU affiliations on clinicians declining to randomize eligible patients were calculated using mixed effects logistic regression modelling.

RESULTS

There were 21,818 patients screened for inclusion in the ADRENAL trial at 69 sites across five countries, out of which 5,501 were eligible, 3,800 were randomized and 659 eligible patients were declined for randomization by the treating clinician. The proportion of eligible patients declined by clinicians at individual ICUs ranged from 0 to41%. In the multivariable model, none of the ICU characteristics were significantly associated with higher clinician decline rate.

CONCLUSIONS

Neither tertiary academic status, nor other site-level variables were significantly associated with increased rate of clinicians declining eligible patients.

Pneumococcal meningitis in adults: a prospective nationwide cohort studY over a 20-year period

Background

The epidemiology and treatment of pneumococcal meningitis has changed with the implementation of conjugate vaccines and the introduction of adjunctive dexamethasone therapy.

Methods

We analyzed episodes of community-acquired pneumococcal meningitis in adults (≥16 years) in the Netherlands, identified by the National Reference Laboratory for Bacterial Meningitis or treating physician between October 1, 1998, and April 1, 2002, and between January 1, 2006, and July 1, 2018. We studied incidence, pneumococcal serotypes, and clinical features. Predictors for unfavorable outcome (Glasgow Outcome Scale score 1–4) were identified in a multivariable logistic regression model. Two physicians independently categorized causes of death as neurological or systemic.

Results

There were 1816 episodes in 1783 patients. The incidence of 7- and 10−7-valent pneumococcal conjugate vaccine serotypes decreased (from 0.42 to 0.06, P = .001; from 0.12 to 0.03 episodes per 100 000 population per year, P = .014). Incidence of nonvaccine serotypes increased (from 0.45 to 0.68, P = .005). The use of adjunctive treatment with dexamethasone increased and was administered in 85% of patients in 2018. In-hospital death occurred in 363 episodes (20%) and unfavorable outcome in 772 episodes (43%). Delayed cerebral thrombosis occurred in 29 patients (2%), of whom 15 patients (52%) died. Adjunctive dexamethasone therapy was associated with favorable outcome (adjusted odds ratio 2.27, P < .001), individual pneumococcal serotypes were not.

Conclusion

Implementation of conjugate vaccines and adjunctive dexamethasone therapy have changed the incidence and outcome of pneumococcal meningitis in adults over the last two decades. Despite recent advances pneumococcal meningitis remains associated with a residual high rate of mortality and morbidity.