Competition and Outcomes in the NHS: Hip Replacement

Discussed yesterday at an OHE Lunchtime Seminar is a new journal article that explores the possible connection between hospital competition and outcomes for non-emergency hip replacement surgery in England.

As the authors[i] note, ‘Health care reforms in England during the last decade have been influenced by the idea that encouraging competition between hospitals, with nationally fixed prices, will increase the quality of care for patients’. Indeed, some research has found a positive connection between competition and outcomes, although the methods and assumptions of some earlier studies have been questioned.

A principal criticism of earlier studies concerned the measures of quality of care that were used. This new analysis benefits from the NHS Patient-Reported Outcome Measures (PROMs) data, collected in England since 2009 for all NHS-funded surgeries for four elective procedures. The current study focuses on one of those: elective hip replacement. PROMs data are collected both before and after treatment, indicating the extent to which the surgery produces improvement in patients’ self-reported health status. Changes in patients’ hip-related health is measured using the Oxford Hip Score.

Following an approach common in the literature on competition, hospital market concentration is used as an indicator of competition, i.e. more hospitals providing care to residents of a geographic area can be expected to create greater competition. Data were collected for 2011–12 for all English NHS hospitals and all elective primary hip replacements. In the analyses, adjustments were made to control for characteristics of patients and/or hospitals that might confound the results.

The ‘key finding’ from the study, the authors state, ‘is that we found no statistically significant association (at the 5% level) between hospital market concentration and the improvement in health of hip patients after surgery’. However, for the 50% of hip patients with less severe problems, greater concentration of hospitals was associated with slightly better patient reported outcomes at the 10% significance level. This indicates that it would be desirable to investigate further with additional years’ data, which the authors intend to do.

This project was funded jointly by the Office of Health Economics and the Nuffield Trust. For additional information, please contact Yan Feng at OHE.