Dialysis for paediatric acute kidney injury in Cape Town, South Africa

The study objectives were to describe the demographics of children who received dialysis for AKI over the study period, to describe the leading causes of AKI in our setting, and to evaluate the distribution of dialysis modalities used and methods of PD catheter insertion and the outcomes associated with these. Outcomes of interest included complications associated with PD catheter insertion, duration of dialysis, complications of dialysis, and survival on each dialysis modality for the cohort as a whole and stratified by weight and age.

Retrospective descriptive review of outcomes in all children aged birth to 18 years who received acute dialysis between 1998 and 2020 at RCWMCH, predominantly in the paediatric intensive care unit (PICU). Data were retrieved from a continuous paper-based database.

The South African healthcare system comprises government-funded and private medical insurance services. Private health care is funded through insurance or out of pocket. The government funds medical care for South Africans without medical insurance at government institutions, with varying degrees of cost-sharing depending on an individual’s income. This includes acute and chronic dialysis and transplantation if individuals meet eligibility criteria. In addition, healthcare for children under 6 years of age is free.

The RCWMCH is a 300-bed, government-funded, tertiary-quaternary referral hospital that manages both government-funded patients and those with private medical insurance or private funding, as some highly specialised services are available only at RCWMCH and not in the private sector. In the kidney unit, the ratio of government to privately funded patients is 70:30, and all are treated equally. There is no selection bias in terms of children being turned down for treatment depending on parental affordability of treatment. This differs from some other LLMIC. Big geographic distances across a large country, however, may contribute to treatment bias for AKI depending on awareness and paediatric knowledge in district and local clinics.

The hospital primarily serves the needs of the greater Cape Town metropolitan region with roughly 1.1 million residents aged 0–14 years in 2021. The overall population increased by approximately 25% over the period of the study [24]. In addition, RCWMCH services a much bigger geographic region including the Western Cape province and the neighbouring Eastern and Northern Cape provinces (totalling 672,000 km², more than 50% of South Africa). Finally, a small number of children are referred from other parts of southern Africa. In 2022, nearly 21 million, or 34% of South Africa’s total population of 62 million people, were children younger than 18 years. Although RCWMCH has a government-imposed paediatric cut-off of 13 years, some older children in chronic services still undergo treatment at the institution.

The hospital has a 22-bed PICU with approximately 1400 admissions per annum across all disciplines, including medical and surgical cases; the latter includes cardiothoracic and neonatal surgery. In addition, the hospital has a paediatric nephrology service that provides acute and long-term care for a wide variety of patients. Most patients undergo acute dialysis within the PICU in keeping with their overall condition, but some patients may also undergo acute dialysis within the high care area of the paediatric nephrology unit. Staffing in the PICU is a 1:1 nurse to patient ratio but may be a pair of senior and junior nurses per 2 beds as opposed to the high care unit where there is a 1:4 nurse to patient ratio. The full spectrum of dialysis modalities for both acute and chronic dialysis (including CKRT including the neonatal Carpe Diem® machine) and for the management of acute metabolic events is available. Most of the nursing staff are trained in PD management (specifically manual PD), but this is not the case for ECD for which there is only a small team of trained staff; ECD requires both nephrology dialysis staff and paediatric nephrology backup. However, our overarching unit policy is the “PD First in Paediatric AKI” approach, i.e. to consider PD (for acute and chronic dialysis) before other options and to use an “Acute/Urgent Start” approach, with PD catheters being inserted at the bedside by non-surgical nephrology or PICU staff [22, 23, 25, 26]. Note that for this study, we have excluded chronic dialysis as much as possible.

This study complied with the ethical guidelines and principles of the Helsinki Declaration of 2008, South African Guidelines for Good Clinical Practice, and the MRC Ethical Guidelines for Research and was approved by the Human Research Ethics committee of the University of Cape Town (Ethics approval UCT HREC Ref: 646/2015 [exp 28/2/2024]).

Over the study period, 593 children (55.0% male) with AKI received dialysis with 463 (78.1%) receiving PD as the first dialysis modality (Table 2). The median age was 9.0 (range 0.03–219.3; IQR 1.3–69.6) months; most children (57.6%) were under 1 year old. The median age for those who received PD only was 6.4 months (IQR 0.9–30.4) vs. 73.9 months (IQR 17.5–113.9) for those who received ECD only (p < 0.001).

The weights of patients dialysed ranged from 0.9 to 62.0 kg (median 7.0 kg, IQR 3.0–16.0 kg), with 38.6% < 5 kg and 61.6% < 10 kg, consistent with the age ranges. More than half (53.5%) of all patients dialysed were under 1 year of age with a weight under 10 kg (58.6%). Overall, 69.1% of patients receiving PD weighed less than 10 kg, whereas 52.3% of children receiving HD weighed over 20 kg. From a clinical perspective, patient median weights remained relatively constant over the study period ranging from 6.0 to 10.8 kg (Supplementary Table 2).

The true prevalence of community vs. hospital acquired AKI cannot be ascertained from our data as these were all children admitted to PICU who required dialysis. The top five categories of conditions associated with AKI requiring dialysis in our study remained fairly constant over time (Supplementary Table 3): medical and surgical cardiac conditions (n = 145, 26.8%), primary kidney pathology (n = 113, 20.9%), sepsis/septic shock requiring inotropic support (n = 128, 24.4%), gastrointestinal conditions (n = 59, 10.9%), and oncological disorders (n = 30, 5.5%) (Table 2). Nine (1.6%) children had toxicity due to an administered toxin/traditional or other medication.

Most children were commenced on dialysis in the PICU, although for 61 (10%) children, dialysis was initiated in the paediatric nephrology high care area while awaiting a bed in the PICU (Table 3). PD consisted predominantly of manual PD, which was used more commonly in infants under 1 year. Automated cycling PD was used in older children weighing > 5 kg (in view of 100 mL fill volumes) which reduced the nursing workload related to manual PD. Overall, most children (463 (78.1%) received only PD, with manual and automated PD being performed in 302 (65.2%) and 154 (33.3%) cases, respectively, with a small number receiving both.

The overall complication rate was 127/560 (22.7%) and included mainly technical problems including blockage or poor drainage (n = 72, 56.7%), leakage (n = 5, 3.9%), displacement of the PD catheter (n = 6, 4.7%), pleural effusion secondary to PD (n = 4, 3.2%), fungal peritonitis requiring discontinuation (n = 3, 2.4%), and bladder perforation (n = 2, 1.6%) not requiring surgical intervention. There were no cases of bacterial peritonitis documented in this study. No bowel perforations were noted, but discoloured ascites on insertion alerted us to the presence of necrotic bowel or peritonitis requiring change in management in 7 (5.5%) cases. Where PD did not function adequately, ECD was used (n = 17, 2.9%).

For 130 (21.9%) children, only ECD was used. For 17 (2.9%) children, both PD and ECD modalities were used; this occurred if one modality was unable to provide adequate dialysis or if PD was not functioning optimally in terms of fluid removal (Table 3). There was a trend toward increasing use of ECD over time. Of the 130 children who received ECD with or without PD, the type of ECD used was recorded for 115, as follows: CKRT 47 (36.2%), Carpe Diem CKRT Neonates 9 (6.9%), CKRT and HD 31 (23.8%), and HD only 28 (21.5%).

In the first 2 quartiles, only 2 (1.2%, 1998–2003) and 18 (11.4%, 2004–2009) HD catheters were used, compared with 37 (24.2%, 2010–2015) and 57 (46.7%, 2016–2020) HD catheters used in the last 2 quartiles studied.

The duration of dialysis for AKI was < 5 days in 337 cases (56.8%), 5–7 days in 70 cases (11.8%), 8–14 days in 50 (8.4%) cases, > 14 days in 47 cases (7.9%), and was not documented in 89 (15.1%) cases (Table 4).

Our study has several limitations, including the paper-based record keeping with approximately 10% missing or incomplete data. In addition, despite our cohort being large by paediatric standards, it remains a single centre study from a less well-resourced region and thus has limited generalizability. PIM and AKI scoring systems, such as the Kidney Disease: Improving Global Outcomes (KDIGO) score, were not able to be applied retrospectively. We do not currently have a PICU follow-up clinic, but some of these patients do filter through to the kidney clinic for follow-up. The long-term outcomes of the children reported here therefore remain unknown.

This study does have significant strengths, in that it has similar numbers to that of Abdelraheem from Sudan [35] and is one of the first of its kind to report a 20-year review of dialysis of children in Africa. The data collection was largely complete and included details on catheter types and dialysis techniques which are infrequently reported. Specifically, we analysed trends over time and found that the use of “PD First for paediatric AKI”, with soft PD catheters inserted with Seldinger technique, by nephrologists/trainees under supervision at the patient’s bedside, is safe, feasible, and successful and can be conducted with simple infrastructure. This should be encouraging to colleagues in similar settings who are beginning to scale up acute dialysis for children with AKI. When done carefully, PD does not need to be considered second best. Cost analysis of PD vs. ECD is beyond the scope of this study and will be reported on separately.

Following our study, we would like to make some recommendations which may be beneficial in settings where paediatric AKI is managed:

Evaluation of the economics of PD vs. HD/CKRT is urgently required. Long-term follow-up clinics for graduates of AKI therapy are also required but need appropriate manpower. In 2013, the International Society of Nephrology launched the “0 by 25” campaign with the goal that no patient should die from preventable or untreated AKI in low-resource areas by 2025 [49]. This paper aims to assist colleagues in other LMIC to achieve this goal, even in the absence of expensive equipment and consumables.