Social Inequities and Access to Kidney Replacement Therapies in Children

By Swasti Chaturvedi, MD (@SwastiThinks)

Social inequities play a significant role in the initiation and progression in chronic kidney disease (CKD) From disadvantage to end-stage renal disease; Progression of chronic kidney disease in rural Manitoba Indigenous communities.

Low socioeconomic status (SES) is associated with increased prevalence of low birth weight and prematurity which has been shown to be linked to a lower nephron mass Early-life course socioeconomic factors and chronic kidney disease There are significant pathophysiological links between low nephron endowment and subsequent kidney disease in adulthood Is low birth weight an antecedent of CKD in later life?. Furthermore, low SES has been associated with reduced glomerular filtration rate, higher albuminuria and higher risk of end stage kidney disease (ESKD) Socioeconomic disparities in chronic kidney disease.

Low SES also impacts access to kidney replacement therapy (KRT). Various studies among adult CKD patients have identified reduced access to KRT and transplant among lower SES or socially disadvantaged populations Indigenous people. Previous studies have recognized multiple barriers that contribute to longer waiting times and poorer transplant access among socially deprived populations such as Indigenous patients. Some of the factors include remoteness, poor access to tertiary dialysis and transplant center access, healthcare practitioner’s attitudes and limited health care literacy IMPAKT. These disparities are further amplified in countries where there is lack of or inadequate universal health coverage and patients need to pay for their treatment Burden, Access, and Disparities in Kidney Disease.

There are very few studies investigating the role of social deprivation in children undergoing KRT initiation in countries with a universal health system. A recent KI Reports Australian study found that Australian Aboriginal children and young adults have rising incidence of ESKD and had poorer access to kidney transplant Rising Incidence of End-Stage Kidney Disease. A study from the United Kingdom found that social deprivation was not associated with late referral, but was strongly associated with reduced access to pre-emptive kidney transplantation Associations between Deprivation.

This brings us to our current study, Social Deprivation Is Associated With Lower Access to Pre-emptive Kidney Transplantation and More Urgent-Start Dialysis in the Pediatric Population by Driollet et al, which examined the association between socioeconomic factors and the different indicators at kidney replacement therapy (KRT) initiation in the French pediatric End Stage Kidney Disease (ESKD) population.

This cross-sectional study included all patients with ESKD who started KRT before 20 years of age in metropolitan France between 2002 and 2015. Data were collected from the comprehensive French Renal Epidemiology and Information Network (REIN), a national KRT registry.

The authors investigated different scenarios at KRT initiation including:

1. KRT modality (dialysis vs. pre-emptive transplantation)

2. Timing of referral to a nephrologist and

3. Dialysis modality

Patients who initiated on KRT were further divided into:

1. Haemodialysis (HD) vs. peritoneal dialysis (PD)

2. Urgent vs. planned start of dialysis

3. Use of catheter vs. use of fistula for HD vascular access.

The authors used European Deprivation Index (EDI), a validated ecological index of deprivation as a proxy for social deprivation. The authors used the continuous version of the EDI and its quintiles to categorize each patient into each 5 groups of deprivation, from the least deprived (Q1) to the most deprived (Q5).

Of the 1262 eligible patients, 31 were excluded because they had not reached ESKD before KRT (Figure 1). Among the remaining 1231 children, 116 were further excluded because of missing residential address data. A total of 1115 patients were thus included in the main statistical analysis.

Figure 1: Flow chart showing the screening and selection of children in the study from the French renal registry (REIN), 2002 to 2015.

Among the 1115 patients included, 59% were males and the median age at KRT initiation was 14.4 years. Most patients were from urban areas (79%) and the commonest cause of ESKD was glomerular or vascular disease (36.8%) (Table 1).

Not surprisingly, the majority of patients started KRT with dialysis (approximately 80%), and only 38.4% were registered preemptively on the transplant waiting list. Interestingly, in terms of patient distribution, quintile 1 to 4 (Q1-Q4) each had 12% to 20% of patients, whereas 39% patients belonged to the most deprived quintile (Q5), thus suggesting that the pediatric ESKD patients came from the most deprived backgrounds.

Patients in Q1 to Q3 of EDI were more likely to be placed preemptively on the waiting list (~48%) than those from quintiles Q4 and Q5 (~ 33%), and patients in Q1 were younger at registration than in Q5 (13.7 years vs. 15.1 years). Moreover, patients in Q1 started dialysis less frequently with HD than those in Q5 (46.0% vs. 65.0%) and more often received a preemptive kidney transplantation (25.8% vs. 15.5%) (Table 2)

Furthermore, the odds of initiating KRT with dialysis (vs. pre-emptive transplantation) increased with increasing EDI even after adjusting for potential confounders (Figure 2) and was almost twice as high for children from the most deprived than for the least deprived area (Q5 vs. Q1: aOR 1.88, 95% CI 1.15–3.07) (Table 3).

Among those who started dialysis, urgent initiation, use of a catheter (vs. arteriovenous fistula) and late referral were seen in more deprived children (Figure 2 andTable 3).

Figure 2: Association between social deprivation measured by the EDI (in continuous) and care indicators at kidney replacement therapy initiation in young patients in Metropolitan France. Adjusted for age at KRT initiation (spline), context of rural environment (rural/urban), and primary kidney disease (4 categories).

The current study does have significant strengths and limitations. A strength of the study was the use of the comprehensive nationwide REIN registry, use of a validated SES index and consideration of multiple important outcomes. A limitation of the study was that the authors could not take into account patient comorbidities, due to missing data. However, the authors have previously shown that adjusting for comorbidities did not affect the results in a prior study investigating the association between EDI and kidney graft failure.

To conclude, this study suggests that lower socioeconomic status is associated with poorer outcomes due to limited access to providers and pre-emptive transplantation. This inequity may lead to the loss of vital productive years in this population of French children.

This study and previous studies highlight the urgent need for policy level changes in reducing the risk of urgent-start dialysis and optimizing access to kidney transplantation in socially deprived children.

The visual abstract by @galindozip summarizes the study.

Read more about how social inequities impact kidney health around the world, and what can be done about them, in the recently concluded NephMadness Social Inequities blog #NephMadness 2022: Inequities Region – AJKD Blog