Socioeconomic inequality, waiting time initiatives and austerity in Scotland: an interrupted time series analysis of elective hip and knee replacements and arthroscopies

Objectives National Health Service (NHS) waiting times have long been a political priority in Scotland. In 2002, the Scottish government launched a programme of investment and reform to reduce waiting times. The effect on waiting time inequality is unknown as is the impact of subsequent austerity measures. Design An interrupted time series analysis between the most and least socioeconomically deprived population quintiles since the introduction of waiting time initiative 1 July 2002 and austerity measures 1 April 2010. Setting All NHS-funded elective primary hip replacement, primary knee replacement and arthroscopy patient data in Scotland from 1 April 1997 to 31 March 2019. Participants NHS Scotland funded patients treated in Scotland. Main outcome measures Trends and changes in mean waiting time. Results There were 135,176, 122,883 and 173,976 NHS funded hip replacement, knee replacement and arthroscopy patients, respectively, in Scotland between 1 April 1997 and 31 March 2019. From 1 July 2002 to 31 March 2010, waiting time inequality between the most and least deprived patients fell and increased thereafter. For hip replacements before 1 July 2002, waiting time inequality increased 1.07 days per quarter; this changed at 1 July 2002 with significant slope change of −2.32 (−3.53, −1.12) days resulting in a decreasing rate of inequality of −1.26 days per quarter. On 1 April 2010 the slope changed significantly by 1.84 (0.90, 2.78) days restoring increasing inequality at 0.58 days per quarter. Knee replacements and arthroscopies had similar results. Conclusions The waiting time initiative in Scotland is associated with a reduction in waiting time inequality benefiting the most socioeconomically deprived patients. Austerity measures may be reversing these gains.