A mixed-methods evaluation of a novel microbiological point-of-care test for patients with respiratory tract infections in primary care

Conference:

2020 SW SAPC Bristol

Talk Code:

1D.2

Presenter:

Tanzeela Y Khalid

Co-authors:

Lorna Duncan, Hannah V Thornton, Gemma Lasseter, Alastair D Hay

Author institutions:

Centre for Academic Primary Care, Population Health Sciences, Bristol Medical School, University of Bristol; NIHR Health Protection Research Unit (HPRU) in Evaluation of Interventions, Bristol Medical School, University of Bristol

Problem

Microbiological point-of-care tests (MPOCTs) are advocated to improve antibiotic prescribing in primary care, where 75-80% of all NHS prescribing takes place. MPOCTs have recently become available for respiratory tract infections (RTIs) but their use has yet to be evaluated in primary care. We aimed to assess if, when and how primary care clinicians use a novel respiratory MPOCT, and to understand their perceptions of MPOCT use.

Approach

We provided four GP practices serving a diverse population of 84,000 patients with the BioMérieux BioFire FilmArray® respiratory MPOCT, each for 6-8 weeks. Patients were eligible if aged >3 months and attending with any acute (≤28 days) suspected RTI. Before testing, clinicians recorded patient characteristics and diagnosis, antibiotic prescribing intention and perceived benefit of antibiotics. Dual throat and nose swabs tested for 17 respiratory viruses and three atypical bacteria. After viewing results, clinicians re-reported diagnosis and perceived antibiotic benefit. 22 practice staff were interviewed to obtain their views of the test, and perceptions regarding its potential for routine use.

Findings

42 clinicians were trained of whom 20 (15 GPs plus 5 nurses) recruited 93 (45 plus 48) patients. Clinicians estimated they recruited one in every three eligible patients. Median participant age was 29 (range 0.5 to 83) years and 57% were female. Staff spent a median of 2.72 minutes setting up the test, which then took 65 minutes to run per sample. 71% were tested <4 hours and 90% <24 hours. All were tested <72 hours, the maximum time required for sample stability. Of the 93 samples tested: 34 (37%) reported no pathogen; 54 (58%) detected at least one virus of which one also reported the presence of one atypical bacterium; two samples found atypical bacteria; and three were inconclusive. Clinical certainty in the patient’s diagnosis was higher when the test returned a positive result for the detection of a pathogen compared to when negative (p<0.001) and diagnostic certainty significantly increased after test use (p=0.03). Clinicians were more likely pre-test to predict the patient would benefit from antibiotics than post-test (p=0.02). Clinical diagnoses changed in 23% of patient’s post-test but <10% were contacted to change their treatment plan. Qualitative staff interviews revealed the test was easy to use and liked, with clear clinical potential, but limitations included sample processing time, one-at-a-time processing and the absence of testing for typical respiratory bacteria.

Consequences

This novel respiratory MPOCT was popular with clinicians and used in a wide variety of patients. MPOCTs could positively impact clinical decision making and antibiotic prescribing, but a randomised controlled trial is needed to establish if they can safely improve patient outcomes. They are more likely to be used if faster, and a greater number of samples can be simultaneously processed.

Submitted by:

Tanzeela Khalid

Funding acknowledgement:

This study is funded by the National Institute for Health Research (NIHR) School for Primary Care Research (project reference 391). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.