Julious 2016.
| Methods |
Study design: cluster‐randomised controlled trial. Aim: to assess the impact of an NHS‐delivered public health intervention on unscheduled medical contacts in children with asthma during September and to perform a health economic analysis of the intervention. Study centres and method of recruitment: 142 UK general practices. Recruitment predominantly via the Clinical Practice Research Datalink (CPRD). A recruitment pack, including study information and an expression of interest form, was sent by post to the preferred contact at the practice to all 433 practices contributing to CPRD in England and Wales at the time of recruitment. Non‐responding practices were sent a reminder e‐mail, followed by a second reminder e‐mail and then final reminders by e‐mail and post. Some practices were also contacted by telephone, by CPRD or the study team at the Sheffield Clinical Trials Research Unit. Practices returned the completed expression of interest form, confirming or updating as necessary the information about the practice held by CPRD. Responses were tracked by CPRD to ensure practices that had replied were not contacted again. The expressions of interest were then forwarded to the study team to contact practices. Dates of study: 29 July 2013 to 30 September 2014. Run‐in period: none. Duration of participation: intervention commenced the week of 29 July 2013. Unscheduled care outcomes measured: September 2013, September to December 2013, September 2013 to August 2014, September 2014. Health economic outcomes measured: 1 August 2013 to 31 July 2014. Consent: ethics approval for the study was given by South Yorkshire Research Ethics Committee on 25 October 2012 (reference number: 12/YH/04). NHS permissions to conduct the study were obtained for all the primary care trusts in England and health boards in Wales. Power: the study was designed to detect a difference of 5% (30% vs 25%) with 90% power and a 2‐sided significance level of 5%, with an intraclass correlation of 0.03 to account for clustering. Based on this, 70 practices were estimated to be required per arm. It was expected that the sample size of 140 practices would equate to approximately 14,000 school‐aged children with asthma. Imputation of missing data, i.e. assumptions made for ITT analysis: analyses of effectiveness were performed as both ITT and PP, with the ITT being primary. If practices stopped submitting data to the CPRD before the end of a given follow‐up period, they were excluded from all analyses for that time period. The health economic analyses were based on the PP population. ITT analyses included all practices for which data were obtained by study period. The PP analyses were the subset of children in the ITT analyses to whom the intervention was delivered as intended by the protocol (i.e. individuals or practices not receiving a letter were excluded from PP analyses). |
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| Participants |
Age (mean, range): 10.5 years, 5 to 16 years. 4‐year‐old children analysed separately. Gender: 60.0% male. Asthma severity: majority most likely mild (severity data not presented). Diagnostic criteria: coded diagnosis of asthma. Eligible participants identified in accordance with pre‐agreed diagnostic codes for asthma by the CPRD. Number recruited: 12,179 Number randomised (intervention, control): 5917, 6262 Number completed (intervention, control): 4411, 4438 Number analysed (intervention, control): 4411, 4438 (Note: figures above are for completing the entire trial until September 2014. ITT analyses of outcomes in September 2013, the primary outcome period, were based on 5305 intervention and 5586 control participants.) Withdrawals: from experimental group: discontinued intervention withdrawal before 30 September 2014: 13 practices, 506 children. From control group: discontinued intervention withdrawal before 30 September 2014: 18 practices, 1824 children. Inclusion criteria: aged between 4 and 16 years on 1 September 2013; coded diagnosis of asthma; prescribed asthma medication March 2012 to March 2013. Exclusion criteria: aged 4 years or under on 1 September 2013 or 16 years or over on 31 August 2013; not considered appropriate for this intervention by GP; not receiving asthma medication; coexisting neoplastic disease. |
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| Interventions |
Intervention: NHS‐delivered public health intervention (a letter sent from the GP to parents/carers of school‐aged children with asthma reminding of the importance to take medications and the need to get sufficient medication sent out during the week commencing 29 July 2013). Comparison: no letter, control arm continue with standard care as usual, no other activity required. Concomitant medication: usual therapy. Excluded medication: none. |
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| Outcomes |
Primary outcome: proportion of children with unscheduled contacts in September 2013. Secondary outcomes: number/proportion/time to first unscheduled contact; number/proportion/time to first unscheduled contacts for respiratory diagnosis; number/proportion/time to first all medical contacts; proportion scheduled contacts; number collecting prescriptions; QALYs gained; and NHS costs. Time points measured:
Primary outcome result: proportion of children with unscheduled contacts in September intervention vs control: 45.2 vs 43.7; OR 1.09, 95% CI 0.96 to 1.25. Secondary outcome results: intervention vs control multiple outcomes and subgroups assessed, most outcomes no significant difference between groups. Proportion prescriptions August 2013: OR 1.43, 95% CI 1.24 to 1.64; number of scheduled contacts per child August 2013: OR 95% CI 1.13, 0.84 to 1.52. No significant difference in unscheduled contacts September to December 2013, September 2013 to August 2014. Mean cost saving across the base case of GBP 36.07 per child and 96.3% probability that the intervention is cost‐saving. Intervention resulted in a QALY loss in 82.9% of samples and a mean loss of 0.00017 QALYs. Adverse events: not reported. |
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| Notes |
Funding: National Institute for Health Research. Subgroups: the primary outcome was similar for 5‐ to 16‐year‐old children who had been prescribed preventative steroids compared to all 5‐ to 16‐year‐old children. Among children aged under 5 years, the differences were larger, and of borderline statistical significance, with the intervention being associated with more unscheduled visits for all subgroups. In all cases, the effect among the PP population was greater than that observed in the ITT population. Post hoc analyses demonstrated that for those who collected a prescription within the last 3 months, there was no difference in unscheduled contacts in September (55.2% vs 54.3% control), whilst for those whose last prescription was collected 3 to 6 months ago, there was an excess of unscheduled contacts in September (42.1% vs 39.7% control). (Data confirmed with study author since they differed between the summary and the main text of the report.) |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Randomised by practice, stratified by size (confirmed by communication with author that the study statistician had no information about practices prior to randomisation other than list size). |
| Allocation concealment (selection bias) | Unclear risk | Sequence generated by 1 of 2 trial statisticians, then revealed to study manager and research assistant. Statisticians had no information about practice other than list size. However, characteristics of individual practices influenced whether the intervention was enacted or not. |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Study team and participants unblinded; this might have affected coding of contacts. Study team had no influence on data capture. Individual practices could choose not send the letter at all or not to send to selected patients. |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Collected via CPRD. Contacts designated as "scheduled", "unscheduled", and "irrelevant" based on an independent adjudication panel comprised of experienced GPs who were blinded to the treatment group. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Missing outcome data due to change in computer system; presumed to be missing completely at random so no imputation. However, this was at least 25% in each group. |
| Selective reporting (reporting bias) | Low risk | All outcomes reported. |
| Other bias | Low risk | No baseline difference in age, gender, and practice size |