Regional Variation in Acute Kidney Injury Requiring Dialysis in the English National Health Service from 2000 to 2015 - A National Epidemiological Study.

BACKGROUND: The absence of effective interventions in presence of increasing national incidence and case-fatality in acute kidney injury requiring dialysis (AKI-D) warrants a study of regional variation to explore any potential for improvement. We therefore studied regional variation in the epidemiology of AKI-D in English National Health Service over a period of 15 years. METHOD: We analysed Hospital Episode Statistics data for all patients with a diagnosis of AKI-D, using ICD-10-CM codes, in English regions between 2000 and 2015 to study temporal changes in regional incidence and case-fatality. RESULTS: Of 203,758,879 completed discharges between 1st April 2000 and 31st March 2015, we identified 54,252 patients who had AKI-D in the nine regions of England. The population incidence of AKI-D increased variably in all regions over 15 years; however, the regional variation decreased from 3·3-fold to 1·3-fold (p<0·01). In a multivariable adjusted model, using London as the reference, in the period of 2000-2005, the North East (odd ratio (OR) 1·38; 95%CI 1·01, 1·90), East Midlands (OR 1·38; 95%CI 1·01, 1·90) and West Midlands (OR 1·38; 95%CI 1·01, 1·90) had higher odds for death, while East of England had lower odds for death (OR 0·66; 95% CI 0·49, 0·90). The North East had higher OR in all three five-year periods as compared to the other eight regions. Adjusted case-fatality showed significant variability with temporary improvement in some regions but overall there was no significant improvement in any region over 15 years. CONCLUSIONS: We observed considerable regional variation in the epidemiology of AKI-D that was not entirely attributable to variations in demographic or other identifiable clinical factors. These observations make a compelling case for further research to elucidate the reasons and identify interventions to reduce the incidence and case-fatality in all regions.

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.