National trends in acute kidney injury requiring dialysis in England between 1998 and 2013

Acute kidney injury (AKI) severe enough to require dialysis is increasing and associated with high mortality, yet robust information about temporal epidemiology of AKI requiring dialysis in England is lacking. In this retrospective observational study of the Hospital Episode Statistics (HES) data set covering the entire English National Health Service, we identified all patients with a diagnosis of AKI requiring dialysis between 1998 and 2013. This incidence increased from 774 cases (15.9 per million people) in 1998–1999 to 11,164 cases (208.7 per million people) in 2012–2013. The unadjusted in-hospital case-fatality was 30.3% in 1998–2003 and 30.2% in 2003–2008, but significantly increased to 41.1% in 2008–2013. Compared with 2003–2008, the multivariable adjusted odds ratio for death was higher in 1998–2003 at 1.20 (95% CI: 1.10–1.30) and in 2008–2013 at 1.13 (1.07–1.18). Charlson comorbidity scores of more than five (odds ratio 2.35; 95% CI: 2.20–2.51) and emergency admissions (2.46 (2.32–2.61) had higher odds for death. The odds for death decreased in patients over 85 years from 4.83 (3.04–7.67) in 1998–2003 to 2.19 (1.99–2.41) in 2008–2013. AKI in secondary diagnosis and in other diagnoses codes had higher odds for death compared with AKI in primary diagnosis code in all three periods. Thus, the incidence of AKI requiring dialysis has increased progressively over 15 years in England. Improvement in case-fatality in 2003–2008 has not been sustained in the last 5 years.