Background: Research in primary care is essential, but recruiting children in this setting can be complex and may cause selection bias. Challenges surrounding informed consent, particularly in an acute clinical setting, can undermine feasibility. The off-protocol use of an intervention nearing implementation has become common in pragmatic randomized controlled trials (RCTs) set in primary care. Aim: To describe how the informed consent procedure affects study inclusion and to assess how off-protocol medication prescribing affects participant selection in a paediatric RCT. Design: A pragmatic RCT evaluating the cost-effectiveness of oral ondansetron in children diagnosed with acute gastroenteritis in primary care out-of-hours services and a parallel cohort study. Method: Consecutive children aged 6 months to 6 years attending primary care out-of-hours services with acute gastroenteritis were evaluated to assess the feasibility of obtaining informed consent, the off-protocol use of ondansetron, and other inclusion/exclusion criteria. Results: The RCTs feasibility was reduced by the informed consent procedure because 39.0% (325/834) of children were accompanied by only one parent. General practitioners prescribed ondansetron off-protocol to 34 children (4.1%), whereof 19 children were eligible for the RCT. RCT-eligible children included in the parallel cohort had fewer risk factors for dehydration than children in the RCT despite similar dehydration assessments by general practitioners. Conclusion: The informed consent procedure and off-protocol use of study medication affect the inclusion rate but had little effect on selection. A parallel cohort study alongside the RCT can help evaluate selection bias, and a pilot study can reveal potential barriers to inclusion.

BackgroundHospital admission rates are increasing for children with acute gastroenteritis. However, it is unknown whether this increase is accompanied by an increase in referral rates from GPs due to increased workloads in primary care out-of-hours (OOH) services.AimTo assess trends in referral rates from primary care OOH services to specialist emergency care for children presenting with acute gastroenteritis.Design & settingThis retrospective cohort study covered a period from September 2007–September 2014. Children aged 6 months to 6 years presenting with acute gastroenteritis to a primary care OOH service were included.MethodPseudonymised data were obtained, and children were analysed overall and by age category. Χ2 trend tests were used to assess rates of acute gastroenteritis, referrals, face-to-face contacts, and oral rehydration therapy (ORT) prescriptions.ResultsThe data included 12 455 children (6517 boys), with a median age of 20.2 months (interquartile range [IQR] 11.6 to 36.0 months). Over 7 years, incidence rates of acute gastroenteritis decreased significantly, and face-to-face contact rates increased significantly (both, P<0.01). However, there was no significant trend for referral rates (P = 0.87) or prescription rates for ORT (P = 0.82). Subgroup analyses produced comparable results, although there was an increase in face-to-face contact rates for the older children.ConclusionIncidence rates for childhood acute gastroenteritis presenting in OOH services decreased and referral rates did not increase significantly. These findings may be useful as a reference for the impact of new interventions for childhood acute gastroenteritis.

Background: Acute gastroenteritis is a common childhood disease with substantial medical and indirect costs, mostly because of referral, hospitalization and parental absence from work. Aim: To determine the cost-effectiveness of adding oral ondansetron to care-as-usual for children with acute gastroenteritis in out-of-hours primary care. Design and setting: A pragmatic randomised controlled trial at three out-of-hours primary care centres, with a follow-up of 7 days. Method: Inclusion criteria were: 1) age 6 months to 6 years; 2) diagnosis of acute gastroenteritis; 3) at least four reported episodes of vomiting 24 hours before presentation, whereof; 4) at least one in the 4 hours before presentation; and 5) written informed consent from both parents. Children were randomly allocated in a 1:1 ratio to either care-as-usual (oral rehydration therapy) or care-as-usual plus one dose of 0.1 mg/kg oral ondansetron. Results: In total, 194 children were included for randomisation. One dose of oral ondansetron decreased the proportion of children who continued vomiting within the first 4 hours from 42.9% to 19.5%, with an odds ratio of 0.4 (95% CI = 0.2–0.7, NNT 4). Total mean costs in the ondansetron group were 31.2% lower (€488 vs €709), and the total incremental mean costs for an additional child free of vomiting in the first 4 hours was −€9 (95% confidence interval, −€41 to €3). Conclusion: A single oral dose of ondansetron for children with acute gastroenteritis, given in out-of-hours primary care settings, is both clinically beneficial and cost-effective.