Six-year single-center survey on AKI requiring renal replacement therapy: epidemiology and health care organization aspects

Evidence regarding hospital-based acute kidney injury (AKI) reveals a continuous increase in incidence over the years, at least in intensive care units (ICU). Fewer reports are available for non critically-ill patients admitted to general or specialist wards other than ICU (non-ICU). The consequence of greater incidence is an increase in therapies such as dialysis; but how the health care organization deals with this problem is not clearly known. Here we quantified the incidence of dialysis-requiring AKI (AKI-D) among patients admitted to a University Hospital which serves a population of 354,000 inhabitants. Between 2007 and 2012, the incidence of AKI-D increased from 209 to 410 per million population (pmp)/year; age of patients and cardiovascular comorbid pathologies also increased. AKI-D was more frequent in non-ICU and 32 % of patients were admitted to ICU. Considering the site of treatment of non-ICU patients, in 2007 the ratio of patients admitted to non-ICU wards apart from Nephrology to those admitted to Nephrology was 1:1, but in 2012 the ratio increased to 2.4:1 (p < 0.05). The complexity of acute disease, measured with the New Simplified Acute Physiology Score (SAPS II), did not reveal differences over the years. The number of dialysis treatments/year increased by 82 %, and the total hours/year increased by 86 %. Low-efficiency daily dialysis was performed in 52.4 % of patients admitted to ICU, but dialysis sessions longer than 8 h were performed in only 40 % of cases. Overall, 6-year mortality was 48.8 %, without significant differences over the years. Mortality in ICU was 65.6 %, and in non-ICU 41.2 % (p < 0.001). Dialysis treatments needed to be continued after hospital discharge in 21 % of patients. We conclude that dialysis-requiring AKI is becoming more common, and that two-thirds of patients are admitted as non-ICU: in these patients, during the last year of the study, the treatment site was more frequently in non-ICUs other than Nephrology. Over the 6-year period, the local healthcare organization had to dispense 80 % more dialysis treatments/year in terms of total number and hours of treatment. One-fifth of surviving patients needed to continue dialysis after hospital discharge. Our data highlight the public health importance of AKI and the need for adequate resources for Nephrology.