Rapid respiratory microbiological point-of-care-testing in primary care: a randomised controlled trial with internal pilot and qualitative and quantitative investigation of microbial, behavioural and antibiotic mechanisms (the RAPID-TEST RCT)

RESEARCH QUESTIONS

Clinical: can the use of a rapid respiratory microbiological point-of-care-test reduce same-day antibiotic prescribing in children and adults presenting to primary care with acute respiratory infections in whom there is uncertainty about antibiotic treatment?

Mechanistic: are there overall (test use vs. no use) and differential (virus detected vs. not detected) effects of test results with respect to clinician beliefs that ‘antibiotics are necessary for this infection’ and thereby antibiotic prescribing? BACKGROUND

Primary care is responsible for 75-80% of NHS antibiotic prescribing, mostly for respiratory infections, despite good evidence of little benefit, driving antimicrobial resistance. ‘Just-in-case’ prescribing is attributed to uncertainty about the microbiological diagnosis and patient prognosis.

Point-of-care-tests (POCTs) are promoted as ‘game-changing’ stewardship tools. Manufacturers are investing heavily, particularly in respiratory microbiological POCTs with current technology providing virus results, including SARS-CoV-2, in 45-120 minutes. Our feasibility study demonstrates primary care clinician acceptability, but there is no evidence regarding safety, efficacy or mechanisms.

METHODS

Design: ‘COVID compliant’ individually randomised controlled trial with mixed-methods investigation of microbial, behavioural and antibiotic mechanisms.

Patients eligible: =/>12 months and presenting with a respiratory infection for which the clinician and/or patient is uncertain and/or disagree about treatment. After consent and baseline data all participants (self-)take throat and nasal swabs. Study champion randomises participants to POCT or no POCT and advises clinician.

Clinicians contact participants to finalise treatment: immediately in control group; after POCT result for intervention group. Participants invited to complete: a symptom diary recording duration and severity of symptoms until resolution or 28 days; and questionnaires at 2 and 6 months about beliefs and intention to consult for similar future illnesses.

GP notes reviewed at 6 months for infection consultations, antibiotic prescribing, and hospital admissions.

After the trial, qualitative interviews will be conducted with clinicians (n=20) and participants (n=30) to understand changes in beliefs and behaviour resulting from the POCT and generate attributes for clinician and patient discrete choice experiments (DCEs). Patient DCE will explore trade-offs made when choosing to visit the GP and the extent POCTs would change this behaviour; clinician DCE will explore trade-offs when deciding about whether and when to use POCT.

514 patients will be randomised to achieve 90% power with 5% significance to detect a 15% absolute reduction in prescribing from 60% in the control group, accounting for 5% attrition. TIMELINES FOR DELIVERY

Months 1 – 6 Trial set-up and approvals; Months 7 – 30 Participant recruitment; Month 15 Assessment of internal pilot; Month 32 Follow-up of last participant; Months 33 – 38 Data cleaning, analysis and final report. ANTICIPATED IMPACT AND DISSEMINATION

Comprehensive plan co-produced with PPI to ensure outputs widely disseminated. Results expected to influence public, patient, clinician, manufacturer and policy-maker views, particularly if no advantage to POCTs. Positive results to inform a future pragmatic trial.