Neighborhood Disadvantage and CKD Progression in Children

The risk for disease progression among children with chronic kidney disease (CKD) is high, a risk that is modified by specific demographic and socioeconomic factors. Evidence suggests that the racial, ethnic, and socioeconomic disparities in outcomes seen in adults with CKD extend to the pediatric CKD population. Black children with CKD are more likely to experience faster disease progression and earlier initiation of kidney replacement therapy (KRT). They are also more likely to initiate dialysis rather than undergo kidney transplantation.

In addition, White children with kidney failure are more likely to have undergone kidney transplantation within 2 years of initiation of dialysis (70% vs 44%, respectively). Children from households with lower income are more likely to develop kidney failure and less likely to be waitlisted for transplant following dialysis initiation.

The Chronic Kidney Disease in Children (CKiD) study is an ongoing multicenter, prospective cohort study examining pediatric CKD. The study collects individual and neighborhood-level socioeconomic  data from participants, including Census block group data. Sara A. Boynton, MPH, and colleagues utilized data from the CKiD study to examine the relationship between neighborhood poverty and deprivation, CKD comorbidities, and disease progression in children with CKD. Results were reported in the American Journal of Kidney Diseases [2022;80(2):207-241].

The outcomes of interest were binary outcomes of short stature, obesity, hypertension, and health care utilization for cross-sectional analysis; a CKD progression end point (defined as incident KRT or 50% loss in estimated glomerular filtration rate [eGFR]), and mode of first KRT for time-to-event analysis. Logistic regression was used to estimate odds ratios with data on health characteristics at the time of the first Census data collection. A Cox proportional hazard model was used to analyze the risk for CKD progression. Multivariable models were adjusted for race, ethnicity, sex, and family income.

The cohort included 578 individuals who completed at least one study visit. Median age was 11.9 years, 60% were male, 26% were Black, and 17% were Hispanic. Approximately 45% of participants reported annual household income of less than $36,000. The majority (92.3%) had lived within the same ZIP code for more than 1 year. Only 2% were uninsured, and 47% had pubic insurance.

Thirteen percent of the cohort had short stature, 18.4% had obesity, and 47.2% had hypertension. In the year prior to the study visit, 28% had been hospitalized and 42% had at least one visit to the emergency department (ED). Median eGFR was 51 mL/min/1.73 m², corresponding to stage 3 CKD. Thirty-two percent of participants included in the analysis progressed to KRT during the follow-up period. The initial mode of KRT was preemptive kidney transplant in 37% of that subgroup.

Neighborhood characteristics of participants’ Census blocks included median household income that was similar to the national median income ($42,148) in 2000. Neighborhood residents were majority non-Black, non-Hispanic.

In analyses of the association between individual and neighborhood characteristics, median neighborhood income was significantly higher for participants whose family income was more than $36,000, and significantly higher for non-Black and non-Hispanic participants. The Area Deprivation Index (ADI) is a composite measure to 17 Census markers that encompass neighborhood poverty, education, employment, and housing. ADI was significantly higher for lower income participants and for Black participants; there was no statistically significant difference between Hispanic and non-Hispanic participants.

The median percentage of neighborhood population that was Black was significantly higher for Black participants than non-Black participants. Likewise, the median percentage of Hispanic neighborhood population that was Hispanic was significantly higher for Hispanic participants than for non-Hispanic participants. Those results suggest that the participants lived in neighborhoods that were relatively homogeneous in terms of race, ethnicity, and socioeconomic status.

Analyses of the association between neighborhood economic factors and participant clinical characteristics revealed that participants in the lowest income neighborhoods were more likely to have short stature than those in the higher neighborhood income quartiles (odds ratio [OR], 1.77; 95% CI, 1.06-2.96), and more likely to have been hospitalized and to have had a visit to the ED in the past year. For participants residing in the lowest income quartile neighborhoods, preemptive kidney transplant was significantly less likely (OR, 0.47; 95% CI, 0.24-0.96).

Following adjustment for individual family income, sex, race, and ethnicity, only the association between lowest neighborhood income and hospitalizations and ED visits remained significant (OR, 1.71; 95% CI, 1.08-2.71 and OR, 1.56; 95% CI, 1.02-2.40, respectively). There was no significant association between high ADI and any health characteristics in the multivariable model.

Results of univariate analysis suggested that participants residing in the lowest neighborhood median income quartile had a nearly 40% greater hazard of reaching the outcome of CKD progression compared with those in the higher quartiles. Following adjustment for participant race, ethnicity, sex, and family income, the association was no longer significant. There was no significant association between ADI and the hazard of the CKD progression outcome in either the univariate or adjusted analyses.

Limitations to the study cited by the authors included limited generalizability, and the lack of data on the clinical indications for urgent health visits or hospitalizations as well as on other neighborhood-level factors such as the presence of food banks or social workers that influence health outcomes. The study data was taken from a single, early study time point, resulting in an inability to determine how changes in neighborhood-level factors were associated with outcomes over time.

In summary, the researchers said, “Neighborhood-level socioeconomic status was associated with poorer health characteristics and CKD progression in univariable analysis. However, the relationships were attenuated after accounting for participant factors including race. A persistent association of neighborhood poverty with hospitalizations and ED suggests an independent effect of socioeconomic status on health care utilization, the causes for which deserve additional study.”

Takeaway Points

1. Researchers conducted an observational cohort study designed to assess the relationship between neighborhood poverty and deprivation and comorbidities and disease progression in children with chronic kidney disease.
2. There were significant associations between the risks for short stature, hospitalization, and emergency department visits and lower neighborhood income.
3. In unadjusted analyses, the likelihood of undergoing a preemptive transplant was decreased with lower neighborhood income, an association that did not persist after adjustment for patient characterisitcs.