A local study has found sepsis-associated acute kidney (SA-AKI) injuries to be common in South African hospitals, with scientists saying more research was needed to investigate and categorise the prevalence of this in critically ill patients, and that new biomarkers were needed to help identify patients at risk of the condition.
Sepsis is a clinical condition in which the inflammatory response to an infection causes organ dysfunction distal to the primary site of infection, and SA-AKI causes significant morbidity and mortality in both children and adults with severe illness, occurring in 35%-70% of critically ill patients and increasing both in-hospital morbidity and mortality.
In the USA, a 22-year retrospective analysis of hospitalised patients from discharge records of non-federal acute care hospitals found that sepsis occurred at an annual rate of 13.7% of hospital admissions. In a single-centre retrospective cohort study in Asia in critically ill patients in the ICU, the reported incidence of acute kidney injury (AKI) was nearly 55% and sepsis was the cause in 49% of cases.[
In a study in South Africa in HIV-positive patients, sepsis was the most common cause of AKI, in 60% of the patients, and in another study also conducted in SA in critically ill patients with AKI, ~41% of AKI was caused by sepsis.
There are numerous risk factors for developing SA-AKI. In a meta-analysis that referenced 47 papers, it was noted that in patients diagnosed with sepsis or septic shock, hypertension, diabetes mellitus (DM), inotropic support and mechanical ventilation had 2.9-fold, 1.4-fold, 1.6-fold, 3.0-fold and 1.6-fold odds ratios, respectively, for developing SA-AKI. In other studies, older age and low serum albumin levels (<35 g/L) were also found to be significant factors associated with SA-AKI.
However, there are very few studies from Africa, and of those, they focused on elucidating the causes of AKI in critically ill patients and included SA-AKI as one of these causes.
For this reason, University of the Witwatersrand researchers, in collaboration with the University of Namibia, conducted a study on local SA-AKI in critically ill patients to determine the burden and associated risk factors in two tertiary centres in Johannesburg. The study also investigated the influence of serum albumin, anaemia, underlying comorbidities and use of inotropes in critically ill patients admitted to ICUs in these two hospitals.
The prospective observational study, published in the SA Medical Journal, was carried out in the ICUs of Charlotte Maxeke Johannesburg Academic Hospital and Chris Hani Baragwanath Academic Hospital from 15 February 2016 to 15 February 2020. The study authors concluded that the rate of SA-AKI was high in the country’s critically ill population, and that development of SA-AKI was associated with older age (>55 years), hypoalbuminaemia and the need for inotropic support. SA-AKI has previously been shown to be a risk factor for mortality.
However, they said, there was a need to find new biomarkers to identify patients at risk of developing SA-AKI, so that appropriate measures could be instituted early to improve outcomes. There is also a need for more studies from Africa to investigate and categorise the prevalence of SA-AKI in critically ill patients.
Study details
Risk factors and outcomes of sepsis-associated acute kidney injury in intensive care units in Johannesburg, South Africa
M D Mweene, G A Richards, G Paget, J Banda, C Dickens.
Published in the SAMJ on 22 December 2022
Background
Sepsis-associated acute kidney injury (SA-AKI) has been shown to be a significant contributor to morbidity and mortality in both children and adults with critical illness. In sub-Saharan Africa, there is a lack of information on factors associated with development of SA-AKI and outcomes after intensive care unit (ICU) admission.
Objectives
To asses the rate of SA-AKI, factors associated with its development, and predictors of mortality at 90 days in critically ill patients admitted to the ICU with sepsis.
Methods
This was a prospective observational study conducted at two of the biggest teaching hospitals in Johannesburg, from 15 February 2016 to 15 February 2020. The study included consecutive patients with confirmed sepsis who were admitted to the ICU within 24 hours of admission to hospital. The primary outcome of the study was development of SA-AKI (defined according to Kidney Disease Improving Global Outcome (KDIGO) criteria), and secondary outcomes were risk factors for SA-AKI and predictors of mortality at 90 days. Multivariate logistic regression analysis was employed to determine the factors associated with SA-AKI and 90-day mortality.
Results
In total, 327 critically ill patients with sepsis admitted to the ICUs were included in the study. The median (interquartile range) age was 39 (30 – 52) years, and 185 patients (56.6%) developed SA-AKI. Of these patients, blacks and whites comprised 91.0% and 6.1%, respectively, and the prevalent comorbidities were HIV/Aids (19.3%), hypertension (14.2%) and diabetes mellitus (10.1%). Patients with SA-AKI were likely to be older and of male gender, and to have cardiovascular disease, malignancies, hypotension and a low serum albumin level. In multivariate analysis, the predictors of SA-AKI were age ≥55 years (odds ratio (OR) 2.43; 95% confidence interval (CI) 1.27 – 4.65), inotropic support (OR 3.61; 95% CI 2.18 – 5.96) and a low serum albumin level (OR 2.93; 95% CI 1.40 – 6.13). SA-AKI and need for inotropic support were respectively associated with 1.9-fold and 1.7-fold increased mortality at 90 days after ICU admission.
Conclusion
SA-AKI was found to be frequent in this study in two tertiary hospital ICUs in Johannesburg, and the need for inotropic support predicted mortality after ICU admission.
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