Acute kidney injury as a risk marker for hospital readmission: a single-center pilot study in the general population of the Parma area

Acute Kidney Injury (AKI) is an important issue for the healthcare system, as it is associated with high mortality and increased risk of readmission, with consequent elevated healthcare resource utilization. We investigated the incidence of AKI based on the examination of the discharge cards of all patients admitted between January 1 2011 and December 31 2015 at the Parma University Hospital, as well as the frequency and type of 30-day hospital readmission in the patients discharged with a first AKI diagnosis (index admission). The mean pooled 5-year incidence of AKI was 2.4%. The mean frequency of 30-day readmission for any disease in patients discharged with a first AKI diagnosis in the selected time interval was 23.1%/year. The main four disease categories, as assessed by the Diagnosis Related Group (DRG) classification, responsible for patient 30-day readmission were a new AKI episode, heart failure, respiratory failure requiring or not requiring mechanical ventilation, and sepsis. The mean lenght of hospital stay of patients discharged with AKI as a principal or secondary diagnosis was 14.4 and 21.8 days, respectively. Based on the evaluation of administrative data from all hospital admissions at the Parma University Hospital in the 2011-2015 5-year period, we conclude that AKI represents a serious challenge for the healthcare system, with high short-term morbidity and increased resource utilization due to frequent hospital readmissions.