The ARID study is a prospective cohort study of people who suffered an AKI during a hospital stay. The ARID study includes people who had a non-elective hospital stay, but did not suffer an AKI. This is to take account of the natural aging effect causing a reduction in kidney function in some people.
There is an increasing recognition that episodes of AKI may have profound longer term effect on renal function and patient outcomes. However, the majority of studies in this area are retrospective and many only focus on specific patient groups. There is therefore a need to examine the long term effects of AKI on patient outcomes in a prospective, UK based study that includes general hospitalised patients from across the entire spectrum of AKI severity.
We set up a long-term, observational case-control study to investigate the effects of AKI on patient outcomes. Cases (patients with AKI) and controls (those screened for AKI but who did not sustain it) were identified from a hospital-wide electronic reporting system for AKI based on the AKIN criteria.
Potential participants were contacted via post and invited to participate; all participants gave informed consent. The control group was matched to AKI patients on a 1:1 basis in terms of baseline eGFR (within the same CKD stage but as closely as possible) and age ± 5yrs. Renal function and proteinuria were measured at 3 months after AKI (or index hospital admission for controls) and will also be measured at 1 and 3 years. Baseline demographics, AKI data (baseline renal function, peak serum creatinine/AKI stage), co-morbidity and hospital stay data were extracted from electronic records.