Does asymmetry in patient recruitment in large critical care trials follow the Pareto principle?

A phase II dose evaluation pilot feasibility randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study)

BACKGROUND

Vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (ICU) and associated with worse clinical course. Trials in adult ICU demonstrate rapid restoration of vitamin D status using an enteral loading dose is safe and may improve outcomes. There have been no published trials of rapid normalization of VDD in the pediatric ICU.

METHODS

We conducted a multicenter placebo-controlled phase II pilot feasibility randomized clinical trial from 2016 to 2017. We randomized 67 critically ill children with VDD from ICUs in Canada, Chile and Austria using a 2:1 randomization ratio to receive a loading dose of enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or placebo. Participants, care givers, and outcomes assessors were blinded. The primary objective was to determine whether the loading dose normalized vitamin D status (25(OH)D > 75 nmol/L). Secondary objectives were to evaluate for adverse events and assess the feasibility of a phase III trial.

RESULTS

Of 67 randomized participants, one was withdrawn and seven received more than one dose of cholecalciferol before the protocol was amended to a single loading dose, leaving 59 participants in the primary analyses (40 treatment, 19 placebo). Thirty-one/38 (81.6%) participants in the treatment arm achieved a plasma 25(OH)D concentration > 75 nmol/L versus 1/18 (5.6%) the placebo arm. The mean 25(OH)D concentration in the treatment arm was 125.9 nmol/L (SD 63.4). There was no evidence of vitamin D toxicity and no major drug or safety protocol violations. The accrual rate was 3.4 patients/month, supporting feasibility of a larger trial. A day 7 blood sample was collected for 84% of patients. A survey administered to 40 participating families showed that health-related quality of life (HRQL) was the most important outcome for families for the main trial (30, 75%).

CONCLUSIONS

A single 10,000 IU/kg dose can rapidly and safely normalize plasma 25(OH)D concentrations in critically ill children with VDD, but with significant variability in 25(OH)D concentrations. We established that a phase III multicentre trial is feasible. Using an outcome collected after hospital discharge (HRQL) will require strategies to minimize loss-to-follow-up.

TRIAL REGISTRATION

CLINICALTRIALS

gov NCT02452762 Registered 25/05/2015.

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.

Recruitment patterns in multicentre randomised trials fit more closely to Price's Law than the Pareto Principle: A review of trials funded and published by the United Kingdom Health Technology Assessment Programme

OBJECTIVE

This review investigates whether the distribution of recruitment to multicentre randomised controlled trials (RCTs) fits the "Pareto Principle", i.e. 80% of participants are recruited by 20% of sites, or Price's Law, i.e. 50% of participants are recruited by the square root of the total number of sites.

METHODS

A review of HTA reports published between 2017 and 2019.

RESULTS

40 RCTs conducted face-to-face recruitment, five recruited via mail-outs and one used both methods. For face-to-face recruitment (n = 41 studies), 80% of participants were recruited by the top recruiting 42.6% of sites; for mail-out methods (n = 6 studies) this was 52.0%. From the square root of sites, 51.3% and 31.8% of participants were recruited for the two recruitment approaches, respectively. Specifically, 3 (7.3%, 95% CI 2.5% to 19.4%) and 20 (48.8%, 95% CI 34.3% to 63.5%) RCTs followed Pareto Principle and Price's Law, respectively. One mail-out recruitment study followed one of these principles, Price's Law. Chief Investigator (CI) sites (n = 24) in face-to-face recruitment studies recruited 18.1% of participants.

CONCLUSION

Face-to-face recruitment to HTA-funded RCTs fits more closely to Price's Law than the Pareto Principle, with the CI's site recruiting nearly a fifth of participants. Since we focussed on HTA-funded RCTs with ≥9 recruiting sites and for which the recruitment method and number recruited by site were known, our findings are limited in their generalizability. However, this trend could be used as a guide to aid in estimating how many sites RCTs need. More accurate estimation may prevent the need for recruitment extensions.

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.

Inequality indices to monitor geographic differences in incidence, mortality and fatality rates over time during the COVID-19 pandemic

BACKGROUND

It is of interest to explore the variability in how the COVID-19 pandemic evolved geographically during the first twelve months. To this end, we apply inequality indices over regions to incidences, infection related mortality, and infection fatality rates. If avoiding of inequality in health is an important political goal, a metric must be implemented to track geographical inequality over time.

METHODS

The relative and absolute Gini index as well as the Theil index are used to quantify inequality. Data are taken from international data bases. Absolute counts are transformed to rates adjusted for population size.

RESULTS

Comparing continents, the absolute Gini index shows an unfavorable development in four continents since February 2020. In contrast, the relative Gini as well as the Theil index support the interpretation of less inequality between European countries compared to other continents. Infection fatality rates within the EU as well as within the U.S. express comparable improvement towards more equality (as measured by both Gini indices).

CONCLUSIONS

The use of inequality indices to monitor changes in geographic inequality over time for key health indicators is a valuable tool to inform public health policies. The absolute and relative Gini index behave complementary and should be reported simultaneously in order to gain a meta-perspective on very complex dynamics.

Transparency, trust and minimizing burden to increase recruitment and retention in trials: a systematic review

OBJECTIVE

To describe patient perspectives on recruitment and retention in clinical trials.

STUDY DESIGN AND SETTING

Systematic review of qualitative studies that reported the perspective of adult patients with any health condition who accepted or declined to participate in clinical trials.

RESULTS

Sixty-three articles involving 1681 adult patients were included. Six themes were identified. Four themes reflected barriers: ambiguity of context and benefit - patients were unaware of the research question and felt pressured in making decisions; lacking awareness of opportunities - some believed health professionals obscured trials opportunities, or felt confused because of language barriers; wary of added burden - patients were without capacity because of sickness or competing priorities; and skepticism, fear and mistrust - patients feared loss of privacy, were suspicious of doctor's motivation, afraid of being a guinea pig, and disengaged from not knowing outcomes. Two themes captured facilitators: building confidence - patients hoped for better treatment, were supported from family members and trusted medical staff; and social gains and belonging to the community - altruism, a sense of belonging and peer encouragement motivated participation in trials.

CONCLUSION

Improving the visibility and transparency of trials, supporting informed decision making, minimizing burden, and ensuring confidence and trust may improve patient participation in trials.