Real world hospital costs following stress echocardiography in the UK: a costing study from the EVAREST/BSE-NSTEP multi-centre study
Authors: Johnson Casey L. , Woodward William , McCourt Annabelle , Dockerill Cameron , Krasner Samuel , Monaghan Mark , Senior Roxy , Augustine Daniel X. , Paton Maria , O’Driscoll Jamie , Oxborough David , Pearce Keith , Robinson Shaun , Willis James , Sharma Rajan , Tsiachristas Apostolos , Leeson Paul ,   the EVAREST/BSE-NSTEP Investigators, Easaw Jacob , Augustine Daniel X. , Abraheem Abraheem , Banypersad Sanjay , Boos Christopher , Bulugahapitiya Sudantha , Butts Jeremy , Coles Duncan , Nageh Thuraia , Hamdan Haytham , Sultan Ayyaz , Jamil-Copley Shahnaz , Kanaganayagam Gajen , Mwambingu Tom , Pantazis Antonis , Papachristidis Alexandros , Rajani Ronak , Rasheed Muhammad Amer , Razvi Naveed A , Rekhraj Sushma , Ripley David P , Rose Kathleen , Scheuermann-Freestone Michaela , Schofield Rebecca , Zidros Spyridon , Wong Kenneth , Fairbarin Sarah , Chandrasekaran Badrinathan , Gibson Patrick , Kardos Attila , Boardman Henry , d’Arcy Joanna , Balkhausen Katrin , Moukas Ioannis , Sehmi Joban S , Firoozan Soroosh 
Published: May 2023

Abstract
Background
Stress echocardiography is widely used to detect coronary artery disease, but little evidence on downstream hospital costs in real-world practice is available. We examined how stress echocardiography accuracy and downstream hospital costs vary across NHS hospitals and identified key factors that affect costs to help inform future clinical planning and guidelines.

Methods
Data on 7636 patients recruited from 31 NHS hospitals within the UK between 2014 and 2020 as part of EVAREST/BSE-NSTEP clinical study, were used. Data included all diagnostic tests, procedures, and hospital admissions for 12 months after a stress echocardiogram and were costed using the NHS national unit costs. A decision tree was built to illustrate the clinical pathway and estimate average downstream hospital costs. Multi-level regression analysis was performed to identify variation in accuracy and costs at both patient, procedural, and hospital level. Linear regression and extrapolation were used to estimate annual hospital cost-savings associated with increasing predictive accuracy at hospital and national level.

Results
Stress echocardiography accuracy varied with patient, hospital and operator characteristics. Hypertension, presence of wall motion abnormalities and higher number of hospital cardiology outpatient attendances annually reduced accuracy, adjusted odds ratio of 0.78 (95% CI 0.65 to 0.93), 0.27 (95% CI 0.15 to 0.48), 0.99 (95% CI 0.98 to 0.99) respectively, whereas a prior myocardial infarction, angiotensin receptor blocker medication, and greater operator experience increased accuracy, adjusted odds ratio of 1.77 (95% CI 1.34 to 2.33), 1.64 (95% CI 1.22 to 2.22), and 1.06 (95% CI 1.02 to 1.09) respectively. Average downstream costs were £646 per patient (SD 1796) with significant variation across hospitals. The average downstream costs between the 31 hospitals varied from £384–1730 per patient. False positive and false negative tests were associated with average downstream costs of £1446 (SD £601) and £4192 (SD 3332) respectively, driven by increased non-elective hospital admissions, adjusted odds ratio 2.48 (95% CI 1.08 to 5.66), 21.06 (95% CI 10.41 to 42.59) respectively. We estimated that an increase in accuracy by 1 percentage point could save the NHS in the UK £3.2 million annually.

Conclusion
This study provides real-world evidence of downstream costs associated with stress echocardiography practice in the UK and estimates how improvements in accuracy could impact healthcare expenditure in the NHS. A real-world downstream costing approach could be adopted more widely in evaluation of imaging tests and interventions to reflect actual value for money and support realistic planning.