Pitfalls in the design and analysis of paediatric clinical trials: a case of a ‘failed’ multi-centre study, and potential solutions

Aim: To increase awareness of possible pitfalls in the design and analysis of a multi-centre randomized clinical trial and to give an overview of alternative study designs and their consequences for power analyses in case of limited availability of trial participants

How to optimise drug study design : pharmacokinetics and pharmacodynamics studies introduced to paediatricians

Objectives In children, there is often lack of sufficient information concerning the pharmacokinetics (PK) and pharmacodynamics (PD) of a study drug to support dose selection and effective evaluation of efficacy in a randomised clinical trial (RCT). Therefore, one should consider the relevance of relatively small PKPD studies, which can provide the appropriate data to optimise the design of an RCT. Methods Based on the experience of experts collaborating in the EU-funded Global Research in Paediatrics consortium, we aimed to inform clinician-scientists working with children on the design of investigator-initiated PKPD studies. Key findings The importance of the identification of an optimal dose for the paediatric population is explained, followed by the differences and similarities of dose-ranging and efficacy studies. The input of clinical pharmacologists with modelling expertise is essential for an efficient dose-finding study. Conclusions The emergence of new laboratory techniques and statistical tools allows for the collection and analysis of sparse and unbalanced data, enabling the implementation of (observational) PKPD studies in the paediatric clinic. Understanding of the principles and methods discussed in this study is essential to improve the quality of paediatric PKPD investigations, and to prevent the conduct of paediatric RCTs that fail because of inadequate dosing.Peer reviewe

The Value of Early Tumor Size Response to Chemotherapy in Pediatric Rhabdomyosarcoma

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood. Results of clinical trials, with three-year event-free and overall survival as primary outcomes, often take 7 to 10 years. Identification of an early surrogate biomarker, predictive for survival, is therefore crucial. We conducted a systematic review to define the prognostic value of early tumor size response in children with IRSG group III rhabdomyosarcoma. The search included MEDLINE/EMBASE from inception to 18 November 2020. In total, six studies were included, describing 2010 patients, and assessed by the Quality in Prognosis Studies (QUIPS) instrument. Four studies found no prognostic value for tumor size response, whereas two studies reported a prognostic effect. In these two studies, the survival rate of patients with progressive disease was not separately analyzed from patients with stable disease, potentially explaining the difference in study outcome. In conclusion, our findings support that early progression of disease is associated with poorer survival, justifying adaptation of therapy. However, in patients with non-progressive disease, there is no evidence that the degree of response is a prognostic marker for survival. Because the vast majority of patients do not have progressive disease, early tumor size response should be reconsidered for assessment of treatment efficacy. Therefore, at present, early surrogate biomarkers for survival are still lacking

Comparison of nuisance parameters in pediatric versus adult randomized trials: a meta-epidemiologic empirical evaluation

BACKGROUND We wished to compare the nuisance parameters of pediatric vs. adult randomized-trials (RCTs) and determine if the latter can be used in sample size computations of the former. METHODS In this meta-epidemiologic empirical evaluation we examined meta-analyses from the Cochrane Database of Systematic-Reviews, with at least one pediatric-RCT and at least one adult-RCT. Within each meta-analysis of binary efficacy-outcomes, we calculated the pooled-control-group event-rate (CER) across separately all pediatric and adult-trials, using random-effect models and subsequently calculated the control-group event-rate risk-ratio (CER-RR) of the pooled-pediatric-CERs vs. adult-CERs. Within each meta-analysis with continuous outcomes we calculated the pooled-control-group effect standard deviation (CE-SD) across separately all pediatric and adult-trials and subsequently calculated the CE-SD-ratio of the pooled-pediatric-CE-SDs vs. adult-CE-SDs. We then calculated across all meta-analyses the pooled-CER-RRs and pooled-CE-SD-ratios (primary endpoints) and the pooled-magnitude of effect-sizes of CER-RRs and CE-SD-ratios using REMs. A ratio < 1 indicates that pediatric trials have smaller nuisance parameters than adult trials. RESULTS We analyzed 208 meta-analyses (135 for binary-outcomes, 73 for continuous-outcomes). For binary outcomes, pediatric-RCTs had on average 10% smaller CERs than adult-RCTs (summary-CE-RR: 0.90; 95% CI: 0.83, 0.98). For mortality outcomes the summary-CE-RR was 0.48 (95% CIs: 0.31, 0.74). For continuous outcomes, pediatric-RCTs had on average 26% smaller CE-SDs than adult-RCTs (summary-CE-SD-ratio: 0.74). CONCLUSIONS Clinically relevant differences in nuisance parameters between pediatric and adult trials were detected. These differences have implications for design of future studies. Extrapolation of nuisance parameters for sample-sizes calculations from adult-trials to pediatric-trials should be cautiously done

Paediatric appendicitis : International study of management in the COVID-19 pandemic

Funding Information: T.W. received a grant from the Swedish Medical Research Council. The Swedish Medical Research Council had no role in any part of the study.Peer reviewe

Improving the Action Research Arm test: a unidimensional hierarchical scale

The Action Research Arm (ARA) test is a performance test of upper extremity motor function which consists of 19 items divided into four hierarchical subtests. This multidimensionality has not yet been tested empirically. To investigate the dimensionality of the ARA test. Cross-sectional study involving a sample of 63 chronic stroke patients. A Mokken scale analysis was performed. The Mokken scale analysis revealed one strong unidimensional scale containing all 19 items, of which the scalability coefficient H was 0.79, while H per item ranged from 0.69 to 0.86. The reliability coefficient rho equalled 0.98, indicating a very high internal consistency. A subset of 15 out of 19 items showed an invariant hierarchical item-ordering. The ARA test is a unidimensional scale. The use of subtests, as proposed in the original description of the instrument, is not supported by the present findings. The 15-item scale presented here can be used for adaptive testing, i.e. using only a selected subset of items based on prior knowledge about the patient's abilities, thus minimizing testing tim

Preface

AimThis was a one-year follow-up of families referred to support services after the parents visited the emergency department due to intimate partner violence, substance abuse or a suicide attempt. Its aim was to evaluate the well-being of any children. MethodsData on families identified a year earlier by the Amsterdam protocol were gathered from child protective services and parent and child self-reports in two Dutch regions from 2012-2015. ResultsWe included 399 children (52%) boys with a median age of eight years (range 1-18) in the study using child protective services data. Of the 101 families who participated in the first measurement, 67 responded one year after the parent's emergency department visit. The results showed that 20% of the children had no or minor problems, voluntary support services were involved in 60% of cases and child protective services were involved in 20%. Compared to their first assessment a year earlier, the children's psychosocial problems had not increased, but this could have been an underestimation due to selective responses. ConclusionThe Amsterdam protocol was valuable in referring families to voluntary support services, but given the ongoing problems in some families, professionals need to carefully monitor whether support services are sufficiently effectiv

Child outcomes after placement of a cervical pessary in women with a multiple pregnancy : A 4-year follow-up of the ProTWIN trial

Acknowledgements We like to thank the research nurses of the Dutch Consortium for Healthcare Evaluation and Research in Obstetrics and Gynecology for their help in finding contact details of the parents.Peer reviewedPublisher PD

Effect of closed endotracheal suction in high-frequency ventilated premature infants measured with electrical impedance tomography

Objective: To determine the global and regional changes in lung volume during and after closed endotracheal tube (ETT) suction in high-frequency ventilated preterm infants with respiratory distress syndrome (RDS). Design: Prospective observational clinical study. Setting: Neonatal intensive care unit. Patients: Eleven non-muscle relaxed preterm infants with RDS ventilated with open lung high-frequency ventilation (HFV). Interventions: Closed ETT suction. Measurements and results: Changes in global and regional lung volume were measured with electrical impedance tomography. ETT suction resulted in an acute loss of lung volume followed by spontaneous recovery with a median residual loss of 3.3% of the maximum volume loss. The median stabilization time was 8 s. At the regional level, the lung volume changes during and after ETT suction were heterogeneous in nature. Conclusions: Closed ETT suction causes an acute, transient and heterogeneous loss of lung volume in premature infants with RDS treated with open lung HFV

Bone mineral density is within normal range in most adult phenylketonuria patients

Low bone mineral density (BMD) as a risk factor for fractures has been a long-standing concern in phenylketonuria (PKU). It is hypothesised that the disease itself or the dietary treatment might lead to a low BMD. Previous studies show conflicting results of BMD in PKU due to differences in age, techniques to assess BMD and criteria used. To assess the prevalence of low BMD and define possible risk factors in a large number of adult, early treated PKU (ETPKU) patients. European centres were invited for a survey, collecting retrospective data including results of dual-energy X-ray absorptiometry (DXA) scans of adult ETPKU patients. BMD of 183 adult ETPKU patients aged 18-46 (median age 28, all females premenopausal) years was lower than in the general population at most skeletal sites but the frequency of low BMD (Z-score <−2) was at maximum 5.5%. No risk factors for low BMD in PKU patients could be identified. Low BMD occurs only in a small subset of PKU patients. DXA scans should be considered for well controlled patients from age 35-40 years and up and on indication in those PKU patients considered to be at increased risk for fractures