Title: The role of hospital organisation, surgical factors, and the enhanced recovery pathway, on patient outcomes and NHS costs following primary hip and knee replacement surgery: spatial and longitudinal analysis of routine data
Funder: Department of Health and Social Care

Abstract: RESEARCH QUESTION To determine the effect of hospital organisation, surgical factors, and the enhanced recovery pathway on patient outcomes and NHS costs of hip/knee replacement. AIMS (1) Identification of hospital organisation, surgical factors and the enhanced recovery pathway, as determinants of geographical variation in patient outcomes and NHS costs (2) Natural experiment to determine the clinical and cost-effectiveness of the enhanced recovery treatment pathway (3) Qualitative study (process evaluation) on implementation of enhanced recovery pathways in four hospital settings POPULATION Primary hip/knee replacement for osteoarthritis PATIENT FORUM Elicit patient’s views on the outcomes of surgery most important to them (patient identified outcomes). Findings from the forum will inform selection of the primary and secondary outcomes of the study. DATA SOURCES UK Clinical Practice Research Datalink; Hospital Episode Statistics; National Joint Registry; NHS Patient Reported Outcome Measures; NHS Hospital and Community Health Service Workforce Statistics; NHS Quarterly Bed Availability and Occupancy data; Supporting Facilities data OUTCOMES Length of stay, readmission, reoperation, complications, PROMs, mortality, NHS resource use and costs, cost-effectiveness EXPOSURES Patient (age, gender, BMI, deprivation, ethnicity, comorbidity, ASA grade); Hospital organisation (operating theatres, day case theatres, available and occupied beds, specialist consultants, hospital volume, day case surgery); Surgical (surgeon volume, operative time, surgeon grade, surgical approach, type of surgery (open, minimally invasive)); Enhanced recovery pathway (1) pre-op planning; 2) reduce physical stress; 3) post-op management; 4) early mobilisation) GEOGRAPHICAL VARIATION IN OUTCOMES Multilevel regression modeling of HES/NJR/PROM linked data will describe the association of hospital organisation, surgical factors and the enhanced recovery pathway on patient outcomes of surgery, adjusting for patient case-mix. Random intercept models will explore geographical variation in outcomes across hospital trusts and Clinical Commissioning Groups. Geographical Information Systems will be used to produce maps depicting variation in outcomes, and graphically display the influence these factors have on explaining such variation. QUALITATIVE PROCESS EVALUATION Ethnographic research in four different hospital settings (specialist orthopaedic centre, teaching hospital, district general hospital, private hospital) selected to represent the main organisational contexts in which hip/knee replacement takes place. A qualitative researcher will approach and recruit health professionals and patients at the hospitals and collect information about enhanced recovery pathways by observing and recording practice and processes, conducting interviews, and collecting relevant documentation. ENHANCED RECOVERY PATHWAY CPRD/HES linked data will be used to estimate the hospital and non-hospital costs following hip/knee replacement. A disease specific Markov model will simulate the costs and health-related quality of life of hip/knee replacement patients before and after introduction of the pathway. A cost-effectiveness analysis will be performed using outcome measures such as Quality-Adjusted Life Years (QALYs) gained. Relative effectiveness measures will be applied to the transition probabilities to model the impact of the new treatment pathway. Interrupted time series analysis will be used to evaluate the impact of the enhanced recovery pathway on trends in rates of outcomes, adjusting for socioeconomic status and case-mix. TIME PLAN Month -6 to 0: Approvals for CPRD and NJR data; Month 0-1: Patient forum; Month 0-6: Obtain HES, CPRD, NJR, PROMs data; Month 3-22: Process evaluation; Month 3-9: Data cleaning and coding; Month 9-18: Statistical analysis; Health economics analysis; Months 18-24: Submission for publication and study close BENEFIT TO NHS The study will provide information to commissioners of healthcare, NHS managers and clinicians on the clinical and cost-effectiveness of the enhanced recovery pathway, together with small area data on geographical variation in surgical outcomes, and knowledge of modifying factors to minimise inappropriate variation

Lay abstract: Osteoarthritis is a leading cause of pain and disability. Many people with severe hip or knee pain caused by osteoarthritis have an operation called total joint replacement. This involves replacing the painful hip or knee joint with an artificial joint. Over 150,000 hip and knee replacement operations take place each year in the NHS and this number is expected to increase. In the NHS patients can choose which hospital they want to have their surgery in. Information on the outcomes of surgery between different hospitals would help patients in making their decision. Outcomes of surgery will vary across different hospitals and areas of the country. This may be explained by a hospital treating more complex and sicker patients, and this must be accounted for. However, differences in patient outcomes could also be explained by how hospitals organised their services, such as bed availability, numbers of operating theatres and specialist surgeons, using new surgical techniques, or centralising care into specialist high volume hospitals. Knowledge of this would help NHS managers to change the way services are organised and reduce variation in outcomes between hospitals. A new patient pathway for hip and knee replacement called enhanced recovery has been introduced in NHS and private hospitals. It is hoped this will benefit patients, through patient education before and after surgery, that includes making changes around the home, exercises to strengthen the joint and changes to diet, to help reduce the risk of complications and speed up a patient’s recovery time. For patients in whom it is suitable, they will further benefit by being able to return home earlier to continue their recuperation at home with appropriate support. This in turn will benefit the hospital by freeing up space for other patients on the waiting list. However, hospitals organise enhanced recovery services in different ways and it is unclear which way is best. In this study we will identify whether the different ways that hospitals organise services for hip and knee replacement patients can lead to improved patient outcomes, and explain why outcomes vary between hospitals. We will produce maps highlighting how outcomes of surgery vary across the country. We will explore organisational processes in the way enhanced recovery has been implemented across different hospital settings. We will look at whether the introduction of enhanced recovery has improved patient outcomes and the potential cost saving to the NHS.

Research activity codes: 8.1 ORGANISATION AND DELIVERY OF SERVICES
Health categories: MUSCULOSKELETAL