Analysis of regional variation in hip and knee joint replacement rates in England using Hospital Episodes Statistics.

OBJECTIVES Total hip and knee joint replacements are effective interventions for people with severe arthritis, and demand for these operations appears to be increasing as our population ages. This study explores regional variations in health care and inequalities in the provision of these expensive interventions, which are high on the UK Government's health agenda. STUDY DESIGN The Hospital Episode Statistics (HES) for England were analysed. The HES database holds information on patients who are admitted to National Health Service (NHS) hospitals in England. METHODS Age-standardized procedure rates were calculated using 5-year age groups with the English mid-year population of 2000 as the reference. Univariate associations between age-standardized operation rates and regional characteristics were assessed using Pearson's correlation coefficient. RESULTS Age and sex-standardized surgery rates vary by 25-30%. For both hip and knee replacement, rates are highest in the South West and Midlands and lowest in the North West, South East and London regions. In the case of knee replacement, there are also marked differences in the sex ratios between regions. The variable that explained most variation in hip replacement rates was the proportion of older people in the region. In the case of knee replacement, the number of NHS centres offering surgery in the region was the main explanatory variable, with regions with fewer centres having the highest provision rates. CONCLUSION These data can help to inform planning of services. They suggest that there may be inequities as well as inequalities in the provision of primary joint replacement surgery in England.