Study design
CLARITY is a multicentre, cluster randomised controlled trial using a hybrid type II implementation effectiveness design. Sites will be randomised using a 1:1 minimisation algorithm into three batches with a staggered start. CLARITY includes an internal pilot study.
The study will involve a total of 60 clusters, with staggered start dates spread over a 6-month period. Roughly half of the clusters will be assigned to receive the intervention, while the remaining clusters will serve as the control group. Each cluster will undergo a total running period of 8 weeks.
Trial setting
The study will take place in NHS trusts across the United Kingdom with emergency surgery services. The evidence based programme will be delivered at the hospital-level, with outcomes assessed at the individual patient-level.
Participants
Individual clinicians within the acute general surgery team. It includes doctors at various stages of their careers (foundation doctors to consultant surgeons), as well as members of the multidisciplinary team (MDT) trained in the assessment of patients with suspected appendicitis (surgical nurse practitioners and physician assistants).
Randomisation
Hospitals will be stratified by bed size (small <400, large >401) and randomised using a minimisation algorithm. The method will allow for a 1:1 allocation and include a stochastic element to prevent lack of allocation concealment and prevent predictability of upcoming assignment.
Population
All consecutive patients aged 16-40 years referred to the acute surgical team with suspected appendicitis, within an 8-week recruitment period. It includes patients reviewed by the surgical team in the emergency department.
Intervention: The CLARITY accurate diagnosis package
We will be delivering the CLARITY accurate diagnosis package across sites in the UK. Within this, our main intervention is the evidence-based programme to improve diagnostic assessment in suspected appendicitis. We will also assess the effectiveness of the CLARITY implementation strategies and access to tools and checklists.
The CLARITY accurate diagnosis package consists of an evidence-based education programme, an implementation checklist and implementation strategies. The package combines education with implementation science. It aims to provide an evidence-based learning programme around how to diagnose and manage appendicitis in a safe way which minimises unnecessary admission and surgery, whilst ensuring people with appendicitis receive prompt treatment. The content of the EBP is based on the latest evidence and provides education on how to provide ‘gold-standard’ care for patients with appendicitis. It does not involve any new interventions which would not be regarded as routine clinical care. The following describes the three components of CLARITY accurate diagnosis package in greater detail:
- Evidence-based education programme: aimed at increasing the adoption of evidence based practice and reducing misdiagnosis, unnecessary admission and negative appendicectomy in suspected appendicitis. This intervention provides accessible information on how to calculate the risk of acute appendicitis in people with right iliac fossa pain and choosing the best diagnostic imaging modality.
- Implementation checklist: A summary of EBP recommendations and access to tools such as prompts or checklists for participants to consider implementing within their practice. We will capture data on whether these tools are useful or used in clinical practice.
- Local implementation strategies: a guide for local facilitators that focuses on environmental implementation strategies. It was developed using results of a national survey of acute surgical teams. It includes a graded strategy system to promote uptake of the education package and to support implementation of its evidence-based recommendations. All participating sites will be asked to report the level of implementation of the proposed strategies.
Controls
Standard care (not exposed to intervention)
Primary outcome
The primary outcome measure is the proportion of people admitted with right iliac fossa pain who do not undergo an operation. This is known as the non-operative admission rate (NOAR). A small minority of non-operative admissions on the suspected appendicitis pathways will be due to other acute GI pathologies treated by the general surgical team (e.g. diverticulitis, colitis, hepatobiliary, tumours of the appendix, small bowel or colon etc.). Furthermore, a few patients with simple appendicitis may be managed nonoperatively. According to RIFT study, these groups constitute around 3% of all RIF pain referrals. Our objective is to reduce the NOAR while accepting that a very small number of nonoperative admissions will remain necessary. We will measure the contribution of these groups to non-operative admissions.
Secondary outcomes
The secondary outcomes will describe the efficacy and safety of the CLARITY package. Of primary concern is safety, as the CLARITY trial seeks to test whether the EBP can reduce unnecessary appendicectomy, whilst maintaining safety. All outcomes in the main study should be measured up to 30 days from attendance/admission, with day 0 being the first day of attendance/admission.
The secondary safety outcomes will include:
- Proportion of patients that were not correctly diagnosed with appendicitis on their first hospital attendance and review by the surgical team (missed or delayed diagnosis)
- The proportion of patients with complicated appendicitis (phlegmon, abscess or perforation)
- Days alive and out of hospital
- Readmission or re-attendance to hospital (including discharge from assessment unit and subsequent reattendance for appendicitis i.e. ‘missed appendicitis’)
- Radiological, percutaneous or endoscopic drainage
- Unplanned admission to critical care (Level 2/3 care)
- Mortality (both inpatient and in the community from any cause)
The secondary safety outcomes for patients who received an operation are:
- Proportion of patients with a negative appendicectomy (appendix normal on histopathological examination)
- Time from symptom onset to decision to operate and to skin incision (in hours)
- Surgical site infection, as defined by the Centers for Disease Control criteria
- Surgical complications, as measured using the Clavien-Dindo classification system
- Reoperation for any cause
Analysis
We have provided a detailed analysis plan in our protocol. In brief, data will be checked and data quality rules will be implemented. Analyses will be performed with respect to the clustered nature of the data. The primary outcome will be compared across intervention groups using mixed effects logistic regression models. Intervention effects will be estimated using restricted maximum likelihood and generalised mixed linear models. For rare events, we will use methods that maximise the likelihood of model convergence, such as propensity score matching.
Pre-planned exploratory analyses will be performed based on hospital and patient characteristics.