Effect of weekend admission on mortality associated with severe acute kidney injury in England: A propensity score matched, population-based study

Abstract

Background: Increased in-hospital mortality associated with weekend admission has been reported for many acute conditions, but no study has investigated “weekend effect” for acute kidney injury requiring dialysis (AKI-D). Methods: In this large, propensity score matched cohort of AKI-D, we examined the impact of weekend admission and in-centre nephrology services in 53,170 AKI-D admissions between 1st April 2003 and 31st March 2015 using a hospital episode statistic dataset. Propensity score matching (PSM) was performed to match 4284 weekend admissions with AKI-D with 14,788 admissions on weekdays. Results: Of the 53,170 admissions with AKI-D in the whole dataset, 12,357 (23%) were at weekends. The unadjusted mortality for weekend admissions was significantly higher compared to admissions on weekdays (406% versus 396%, p 0046). However, in multivariable analysis of the PSM cohort, the odds of death for weekend admissions with AKI-D was 101 (95%CI 093,109). Mortality was higher for weekend admissions in West Midlands (odds ratio (OR) 132, 95% confidence interval (CI) 105, 166) and lower in East of England (OR 077, 95% CI 059, 100) but was not different to weekday admissions in all other regions. In 2003–04, weekend admissions had lower odds of death (OR 045, 95%CI 021, 096) and in 2010–11 higher odds of death (OR 128, 95%CI 100, 163) but in the other ten years observed, there was no significant difference in mortality between weekday and weekend admissions. Provision of in-centre nephrology services was associated with lower odds of death at 057 (95% CI 054, 062). Conclusions: Weekend admissions in patients with AKI-D had no effect on mortality. Further research is warranted to elucidate the reasons for the lower mortality in hospitals with in-centre nephrology services.