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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: ATLAS


To determine the effect of hospital organisation, surgical factors, and the enhanced recovery after surgery (ERAS) pathway on patient outcomes and NHS costs of hip/knee replacement.

(1) Statistical analysis of national linked data to explore geographical variations in patient outcomes of surgery. (2) A natural experimental study to determine clinical effectiveness of ERAS. (3) A qualitative study to identify barriers and facilitators to change. (4) Health economics analysis to establish NHS costs and cost-effectiveness.

Data from the National Joint Registry, linked to English Hospital Episode Statistics and Patient reported Outcome Measures in both the geographical variation and natural experiment studies, together with the economic evaluation.
The ethnographic study took place in four hospitals in a region of England.

Qualitative study: 38 health professionals working in hip/knee replacement services in secondary care. 37 patients receiving hip/knee replacement.

Natural experiment – Implementation of ERAS at each hospital between 2009 to 2011.
ERAS is a complex intervention focusing on several areas of patients’ care pathways through surgery: pre-operatively (patient in best possible condition for surgery); peri-operatively (patient has best possible management during and after operation); post-operatively (patient experiences best rehabilitation).

Main outcome measures
Patient reported pain and function (Oxford hip/knee scores); 6-month complications; length of stay (LOS); bed day costs; revision surgery within 5-years.

Geographical study – There is potentially unwarranted variations in patient outcomes of hip/knee replacement surgery. This variation cannot be explained by differences in patients case-mix, surgical, or hospital organisational factors.
Qualitative – Successful implementation depends on empowering patients to work towards their recovery, providing post-discharge support and promoting successful multi-disciplinary team working. Care processes were negotiated between patients and healthcare professionals. ‘Good care’ remains an aspiration, particularly in the post-discharge period.
Natural experiment – LOS has declined substantially, pain and function have improved, revision rates are in decline and complication rates remain stable. The introduction of a national ERAS programme maintained improvement but did not alter the rate of change already underway.

Health economics – Costs are high in the year of joint replacement and remain higher in the subsequent year after surgery. There is a strong economic incentive to identify ways of reducing revisions and complications following joint replacement. Published cost-effectiveness evidence supports enhanced recovery pathways as a whole.
Short duration of follow-up data prior to ERAS implementation, and missing data, particularly for hospital organisation factors.

No evidence was found to show that ERAS had substantially impacted on longer term downward trends in costs and LOS. Trends of improving outcomes were seen across all age groups, in those with and without co-morbidity, and had begun prior to the formal ERAS role out. Reductions in LOS have been achieved without adversely impacting on patient outcomes. Yet there still remains substantial variation in outcomes between hospital trusts.

Future work
There is still work to be done to reduce and understand unwarranted variations in outcome between individual hospitals.

Acceptance Date Aug 12, 2019
Publication Date Feb 11, 2020
Journal Health Services and Delivery Research
Print ISSN 2050-4349
Publisher NIHR Journals Library
Keywords enhanced recovery; cost effectiveness; patient outcomes; arthroplasty; epidemiology
Publisher URL


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