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.