Acute Kidney Injury in Urology Patients: Incidence, Causes and Outcomes

Background: acute kidney injury (aki) is common in hospitalised patients and is associated with high mortality rates. however, the epidemiology of aki in urology patients may differ due to a higher proportion of post-renal causes and surgical procedures that result in the intentional removal of renal parenchyma. objectives: we performed a study to examine the incidence, aetiology and outcomes of aki in a urological population. patients and methods: we performed a single-centre observational study including all hospitalised patients who sustained aki within the urology department over an 18 month period. patients with aki were prospectively identified by a hospital-wide, electronic aki reporting system that also allows demographic, hospital admission and co-morbidity data collection. data regarding aetiology of aki and details of surgical procedures were added retrospectively by manual case-note search. results: 587 episodes of aki occurred in 410 urology patients, giving an overall incidence of 6.7%. 137 (33.4%) were elective cases of whom 58 had undergone nephrectomy (radical and partial). urinary obstruction and sepsis were the predominant causes of aki in the 273 patients (66.6%) admitted as an emergency. overall 30-day mortality was 7.8%; increasing severity of aki was associated with mortality (4.8% in stage 1, 9.1% in stage 2, 14.9% in stage 3, p = 0.007). at time of discharge, only 57.7% of patients had recovered pre-morbid renal function. the observational nature of this study is a limitation, preventing determination of causality of associations. conclusions: aki is common in urology patients. the underlying aetiologies of aki in this group may explain a lower overall mortality, although increasing aki severity remains a marker of patients at higher risk of poor outcomes. the low rate of renal recovery suggests that urology patients who sustain aki are exposed to a significant risk of ckd and its attendant consequences for long term health.