Post-operative Acute Kidney Injury: incidence, risk factors and outcomes in the Yaoundé Central Hospital

André Claude Mbaga Ntjam (
Surgery and specialities, FMBS, The University of Yaoundé I
July, 2015


Abstract Background Postoperative acute kidney injury (AKI) is associated with long hospital stay, increased economic costs and a high mortality. In developed countries, its incidence ranges from 1 to 7% for non-cardiac surgery and even higher for cardiac surgery. The true incidence is unknown in sub-Saharan Africa, but post-operative AKI accounts for over 6% of all cases of AKI. Surgical, anaesthetic and patient-dependent factors have been identified as risk factors. Given the increasing burden of AKI, it is important to understand the epidemiology of this condition in order to design effective preventive strategies. Objectives
We aimed to determine the incidence of postoperative AKI, identify its risk factors and describe the patient and renal outcomes after 3 months of diagnosis Materials and methods we therefore conducted a prospective cohort study from January to May 2015 at surgical services of the Yaoundé Central Hospital. Consenting patients undergoing surgery in the study site were included. Patients for ambulatory, eye, ear, nose and throat surgeries were excluded. Patients with end stage renal disease were also excluded. Relevant socio-demographic and clinical data were collected through patient interviews, medical records, anaesthetic records and per-operative surgical notes. Serum creatinine was measured preoperatively and 48 hours after surgery to confirm the diagnosis of AKI. For patients with AKI, serum creatinine was again evaluated on hospital discharge and after 3 months. The diagnosis of AKI was based on Kidney Disease: Improving Global Outcomes (KDIGO) criteria 2012 and post-operative AKI was defined as an increase in serum creatinine by0.3 mg/dl within 48 h after surgery. All participants were followed up during their hospitalisation and patients with AKI were followed up for 3 months. Patient outcomes noted were mortality, need for dialysis, access to dialysis, and recovery of renal function. Data was analysed using the
Post-operative Acute Kidney Injury: incidence, risk factors and outcomes in the Yaoundé Central Hospital
André Claude Mbaga1, Jacqueline Ze Minkande1, Gloria Ashuntantang1, Agnès Esiene1
1 Faculty of Medicine and Biomedical Sciences
Epi-Info software version 3.5.4 and IBM-SPSS Version 20.0. Multiple logistic regression models was used to identify independent risk factors of post-operative AKI p-values <0.05 were considered statistically significant.
Results Of the 215 eligible participants, 14 were excluded. A total of 201(130 women) were included. The mean (±SD) age was 38.5 ± 15.2 years, (range 16-80) years. The most represented surgeries were obstetrics and gynaecology (n= 41.8%), abdominal (n= 28.3%) and orthopaedics (n= 17.9%). A total of 17(8.5%) patients developed post-operative AKI. The patient’s stages of AKI were 10 (58.8%) at stage 1, 4(23.5) at stage 2 and 3(17.6%) at stage 3. Age> 65 yrs (P=0.03), emergency surgery (P=0.03), high anaesthetic risk(P=0.01), high risk of infection(P=0.01) and intestinal resection surgery(0.02) were independent risk factors of AKI. In-hospital mortality was significantly higher in patients with AKI (23.5% vs 1.6% p= 0.008). Dialysis was indicated in 3(17.6%) of 17 patients but only 01(33.33%) was effectively dialyzed. At 3 months, 4 patients (23.5%) died, 11 (64.71%) had complete recovery of renal function, 01 (5.88 %) partial renal recovery and 01 (5.88 %) was lost to follow-up. Conclusion The incidence of postoperative acute kidney injury is high. Renal outcomes are good but mortality remains high in those without access to dialysis. The risk factors of post-operative AKI identified in this study call for the development of cost-effective preventive strategies such as screening of risk groups.
Key words: AKI, post-operative, incidence, risk factors, outcomes