Do expanded seven-day NHS services improve clinical outcomes? Analysis of comparative institutional performance from the “NHS Services, Seven Days a Week” project 2013–2016

BACKGROUND: The cause of adverse weekend clinical outcomes remains unknown. In 2013, the “NHS Services, Seven Days a Week” project was initiated to improve access to services across the seven-day week. Three years on, we sought to analyse the impact of such changes across the English NHS. METHODS: Aggregated trust-level data on crude mortality rates, Summary Hospital-Level Mortality Indicator (SHMI), mean length of stay (LOS), A&E admission and four-hour breach rates were obtained from national Hospital Episode Statistics and A&E datasets across the English NHS, excluding mental and community health trusts. Trust annual reports were analysed to determine the presence of any seven-day service reorganisation in 2013–2014. Funnel plots were generated to compare institutional performance and a difference in differences analysis was performed to determine the impact of seven-day changes on clinical outcomes between 2013 and 2014, 2014–2015 and 2015–2016. Data was summarised as mean (SD). RESULTS: Of 159 NHS trusts, 79 (49.7%) instituted seven-day changes in 2013–2014. Crude mortality rates, A&E admission rates and mean LOS remained relatively stable between 2013 and 2016, whilst A&E four-hour breach rates nearly doubled from 5.3 to 9.7%. From 2013 to 2014 to 2014–2015 and 2015–2016, there were no significant differences in the change in crude mortality (2014–2015 p = 0.8, 2015–2016 p = 0.9), SHMI (2014–2015 p = 0.5, 2015–2016 p = 0.5), mean LOS (2014–2015 p = 0.5, 2015–2016 p = 0.4), A&E admission (2014–2015 p = 0.6, 2015–2016 p = 1.0) or four-hour breach rates (2014–2015 p = 0.06, 2015–2016 p = 0.6) between trusts that had implemented seven-day changes compared to those which had not. CONCLUSIONS: Adverse weekend clinical outcomes may not be ameliorated by large scale reorganisations aimed at improving access to health services across the week. Such changes may negatively impact care quality without additional financial investment, as demonstrated by worsening of some outcomes. Detailed prospective research is required to determine whether such reallocation of finite resources is clinically effective. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12913-017-2505-8) contains supplementary material, which is available to authorized users.