An audit of acute kidney injury : a prospective study of the epidemiology, management and outcome of patients with acute kidney injury, over a 12 month period at Groote Schuur Hospital, Cape Town, South Africa

Includes bibliographical references.Introduction: Acute kidney injury results from a rapid decline in kidney function. There are many potential causes, some of which are preventable. It carries the risks of mortality, progression to chronic kidney disease and worsening of pre-existing chronic kidney disease. There is a scarcity of data on the epidemiology of acute kidney injury in sub-Saharan Africa. The aims of this study were to describe the epidemiology of acute kidney injury at Groote Schuur hospital, and factors associated with mortality and renal recovery. Methods: This was a prospective observational study of patients with acute kidney injury, referred to Groote Schuur Hospital Renal Unit from the 8th of July 2012 to the 8th of July 2013. Ethics approval was granted by the University of Cape Town Human Research Ethics Committee. We excluded patients younger than 13 years, kidney transplant patients, and those not fulfilling the consensus definition of acute kidney injury according to the Kidney Disease: Improving Global Outcomes (KDIGO) group. Data on patient demographics, medical history, clinical observations, investigations, and cause of acute kidney injury was collected from a clerking sheet designed for the study. Patients were followed up at, or after 3 months (90 days) for assessment of survival and renal recovery. The main outcomes were recovery of renal function and mortality at 3 months. Data was entered into an Excel spreadsheet, and imported onto Stata 12.1 for analysis. Results: A total of 366 patients were included. The median age was 44 years (IQR 14-82). Of these 214 were male (58.5%). Referrals were from medical, surgical and obstetrics and gynaecology departments. The majority, 217 (59.3%) were medical referrals. Most, 265 (72.4%) had community acquired acute kidney injury. The majority of the 101 patients with hospital acquired acute kidney injury, 72 (71.3%) had severe, stage 3 acute kidney injury. Hypertension was the commonest co-morbidity, present in 152 (41.5%) of the patients. There were 75 (20.6%) HIV positive patients. Acute tubular necrosis was the most common cause of acute kidney injury, identified in 251 (68.6%) patients. Renal biopsies were carried out in 36 (9.8%) patients. More than half, 202 (55.2%), of the patients were in the intensive care unit, while 204 (55.7%) were dialysed. Fluid input was recorded in 140 patients (38.3%). Overall 3 month mortality was 38.8% (142 patients). Of the 224 surviving patients, 119 (53.1%) had a follow up serum creatinine. Of these, 95 (80.5%) had full renal recovery, and 4 (3.4%) went on to end stage renal disease. On multivariate analysis, mechanical ventilation was strongly associated with mortality at 3 months (OR 2.46, p-value 0.0 19, 95% CI 1.41-4.03). Sepsis had a borderline significant association with 3 month mortality (OR 1.83, P-value 0.066, 95%CI 1.02 – 3.27), as did prolonged time to dialysis (OR 1.93, p-value 0.080, 95% CI 0.93 – 4.03). HIV was not associated with mortality on univariate analysis (OR 1.07, p-value 0.801, 95%CI 0.64-1.80). Conclusions: Acute kidney injury carries a high mortality risk, most significant in mechanically ventilated patients. Sepsis and, in those dialysed, late dialysis, may be associated with a high risk of mortality. Efforts to reduce hospital acquired acute kidney injury and to improve patient fluid balance chart records should be made