Kidney disease in life-course socioeconomic context: the Atherosclerosis Risk in Communities (ARIC) Study

Medical Nutrition Therapy for Chronic Kidney Disease: Low Access and Utilization

CKD affects approximately half of US adults aged 65 years and older and accounts for almost 1 out of every 4 dollars of total Medicare fee-for-service spending. Efforts to prevent or slow CKD progression are urgently needed to reduce the incidence of kidney failure and reduce health care expenditures. Current CKD care guidelines recommend medical nutrition therapy (MNT), a personalized, evidence-based application of the Nutrition Care Process (assessment, intervention, diagnosis, and monitoring and evaluation) provided by registered dietitian nutritionists (RDNs) to help slow CKD progression, improve quality of life, and delay kidney failure. MNT is covered by Medicare Part B and most private insurances with no cost sharing. Despite recommendations that patients with CKD receive MNT and insurance coverage for MNT, utilization remains low. This article demonstrates low utilization of MNT and inadequate numbers of RDNs and RDNs who are board certified in renal nutrition relative to the estimated number of Medicare eligible adults with self-reported diagnosed CKD by state, with noted disparities across states. We discuss interventions to increase MNT utilization, such as improving MNT reimbursement, augmenting accessibility of RDNs via telenutrition services and increasing health care provider promotion of MNT and referral to MNT to optimize CKD outcomes.

Fluoxetine partially alleviates inflammation in the kidney of socially stressed male C57 BL/6 mice

Stress-related illnesses are linked to the onset and progression of renal diseases and depressive disorders. To investigate stress-induced changes in the renal transcriptome associated with the development of depressive behaviors, we generated here a chronic social defeat stress (CSDS) model of C57 BL/6 male mice and then performed RNA sequencing of the kidneys to obtain an inflammation-related transcriptome. Administration of the antidepressant drug fluoxetine (10 mg·kg-1 ·day-1 ) during CSDS induction could partially alleviate renal inflammation and reverse CSDS-induced depression-like behaviors. Moreover, fluoxetine also modulated gene expression of stress-related hormone receptors, including prolactin and melanin-concentrating hormone. These results suggest that CSDS can induce gene expression changes associated with inflammation in the kidney of C57 BL/6 male mice, and this inflammation can be treated effectively by fluoxetine.

Liver Fibrosis Scores and Prostate Cancer Risk and Mortality in the Atherosclerosis Risk in Communities Study

Subclinical liver impairment due to fibrosis could influence the development and detectability of prostate cancer. To investigate the association between liver fibrosis and prostate cancer incidence and mortality, we included 5,284 men (mean age: 57.6 years, 20.1% Black) without cancer or liver disease at Visit 2 in the Atherosclerosis Risk in Communities study. Liver fibrosis was assessed using the aspartate aminotransferase to platelet ratio index, fibrosis 4 index (FIB-4), and nonalcoholic fatty liver disease fibrosis score (NFS). Over 25 years, 215 Black and 511 White men were diagnosed with prostate cancer, and 26 Black and 51 White men died from the disease. We estimated HRs for total and fatal prostate cancer using Cox regression. FIB-4 [quintile 5 vs. 1: HR = 0.47, 95% confidence interval (CI): 0.29-0.77, Ptrend = 0.004] and NFS (HR = 0.56, 95% CI: 0.33-0.97, Ptrend = 0.03) were inversely associated with prostate cancer risk in Black men. Compared with no abnormal score, men with ≥1 abnormal score had a lower prostate cancer risk if they were Black (HR = 0.46, 95% CI: 0.24-0.89), but not White (HR = 1.04, 95% CI: 0.69-1.58). Liver fibrosis scores did not appear to be associated with fatal prostate cancer in Black or White men. Among men without a clinical diagnosis of liver disease, higher liver fibrosis scores were associated with lower incidence of prostate cancer in Black men, but not in White men, and not with fatal prostate cancer in either race. Further research is needed to understand the influence of subclinical liver disease on prostate cancer development versus detectability and the racial differences observed.

PREVENTION RELEVANCE

Investigating the link between liver fibrosis and prostate cancer risk and mortality, our study reveals the potential influence of liver health on prostate cancer development and on detection using PSA test, urging further research to understand the differential findings by race and to optimize prevention and intervention strategies.

Prevalence of Self-Reported Kidney Disease in Older Adults by Sexual Orientation: Behavioral Risk Factor Surveillance System Analysis (2014-2019)

SIGNIFICANCE STATEMENT

Studies discusses CKD disparities by age, race and ethnicity, and socioeconomics. However, despite well-documented disparities in CKD risk factors in LGBT+ adults, limited literature addresses CKD prevalence in this population. This analysis uses Behavioral Risk Factor Surveillance System (2014-2019) data to compare self-reported kidney disease prevalence in LGBT+ older adults (older than 50 years) with their heterosexual peers. Our findings indicate that LGBT+ older adults have higher rates of self-reported kidney disease and a higher incidence of CKD risks including smoking, activity limitations, adverse health outcomes, and limited access to health care, housing, and employment. These results support increasing access to screening for CKD risk factors, providing culturally responsive health care, and addressing societal drivers of vulnerability in older LGBT+ adults.

BACKGROUND

Existing research documents disparities in CKD by age, race and ethnicity, and access to health care. However, research on CKD in lesbian, gay, bisexual, and trans (LGBT+) older adults, despite their higher rates of diabetes, heart disease, smoking, and alcohol use, is limited.

METHODS

Pooled data from the Behavioral Risk Factor Surveillance System (2014-2019) for 22,114 LGBT+ adults and 748,963 heterosexuals aged 50 and older were used to estimate the prevalence of self-reported kidney disease. Logistic regressions were used to compare older adults by sexual orientation.

RESULTS

Older LGBT+ men (adjusted odds ratio=1.3; 95% confidence interval [CI], 1.09-1.54) were more likely than their heterosexual counterparts to report kidney disease, after controlling for sociodemographic factors, health behaviors, access to health care, and self-reported coronary heart disease, HIV, and diabetes; LGBT+ men and women also reported higher incidences of known risk factors for CKD. For example, both LGBT+ men (odds ratio [OR]=1.39; [95% CI], 1.26-1.54) and LGBT+ women (OR=1.39; [95% CI], 1.25-1.55) were more likely to be smokers and have a higher incidence of activity limitations, adverse health outcomes, and limited access to health care, housing, and employment.

CONCLUSION

These results support increasing access to screenings for CKD risk factors, providing preventative education and culturally responsive and affirming care, and addressing other societal drivers of vulnerability in older LGBT+ adults. The findings also support the value of interventions that address the interaction between CKD risk factors and the social marginalization that older LGBT+ adults experience.

Individual Life-Course Socioeconomic Position and Hearing Aid Use in the Atherosclerosis Risk in Communities Study

BACKGROUND

To measure the association between individual life-course socioeconomic position (SEP) and hearing aid use, we examined childhood and adulthood socioeconomic variables collected at the Atherosclerosis Risk in Communities (ARIC) study baseline visit (1987-1989)/Life Course Socioeconomic Status study (2001-2002) and hearing aid use data collected at visit 6 (2016-2017).

METHODS

ARIC is a prospective cohort study of older adults (45-64 years) recruited from 4 U.S. communities. This analysis included a subset of 2 470 participants with hearing loss at visit 6 (≥25 decibels hearing level [dB HL] better-ear) with complete hearing aid use data. Childhood SEP variables included parental education, parental occupation, and parental home ownership. Young and older adulthood SEP variables included income, education, occupation, and home ownership. Each life epoch was assigned a score ranging from 0 to 5 and then summed to calculate the individual cumulative SEP score. Multivariable-adjusted logistic regression was used to estimate the association between individual cumulative SEP and hearing aid use. Missing SEP scores were imputed for participants with incomplete socioeconomic data.

RESULTS

Of the 2 470 participants in the analytic cohort (median [interquartile interval] age 79.9 [76.7-84.0], 1 330 [53.8%] women, 450 [18.2%] Black), 685 (27.7%) participants reported hearing aid use. Higher cumulative SEP was positively associated with hearing aid use (odds ratio [OR] = 1.09, 95% confidence interval [CI]: 1.04-1.14), and slightly stronger for childhood (OR = 1.09, 95% CI: 1.00-1.20) than older adulthood SEP score (OR = 1.06, 95% CI: 0.95-1.18).

CONCLUSIONS

In this community-based cohort of older adults with hearing loss, higher individual life-course SEP was positively associated with hearing aid use.

Health Data-Driven Machine Learning Algorithms Applied to Risk Indicators Assessment for Chronic Kidney Disease

PURPOSE

As global aging progresses, the health management of chronic diseases has become an important issue of concern to governments. Influenced by the aging of its population and improvements in the medical system and healthcare in general, Taiwan's population of patients with chronic kidney disease (CKD) has tended to grow year by year, including the incidence of high-risk cases that pose major health hazards to the elderly and middle-aged populations.

METHODS

This study analyzed the annual health screening data for 65,394 people from 2010 to 2015 sourced from the MJ Group - a major health screening center in Taiwan - including data for 18 risk indicators. We used five prediction model analysis methods, namely, logistic regression (LR) analysis, C5.0 decision tree (C5.0) analysis, stochastic gradient boosting (SGB) analysis, multivariate adaptive regression splines (MARS), and eXtreme gradient boosting (XGboost), with estimated glomerular filtration rate (e-GFR) data to determine G3a, G3b & G4 stage CKD risk factors.

RESULTS

The LR analysis (AUC=0.848), SGB analysis (AUC=0.855), and XGboost (AUC=0.858) generated similar classification performance levels and all outperformed the C5.0 and MARS methods. The study results showed that in terms of CKD risk factors, blood urea nitrogen (BUN) and uric acid (UA) were identified as the first and second most important indicators in the models of all five analysis methods, and they were also clinically recognized as the major risk factors. The results for systolic blood pressure (SBP), SGPT, SGOT, and LDL were similar to those of a related study. Interestingly, however, socioeconomic status-related education was found to be the third important indicator in all three of the better performing analysis methods, indicating that it is more important than the other risk indicators of this study, which had different levels of importance according to the different methods.

CONCLUSION

The five prediction model methods can provide high and similar classification performance in this study. Based on the results of this study, it is recommended that education as the socioeconomic status should be an important factor for CKD, as high educational level showed a negative and highly significant correlation with CKD. The findings of this study should also be of value for further discussions and follow-up research.

A Scoping Review of Life-Course Psychosocial Stress and Kidney Function

Increased exposure to maternal psychosocial stress during gestation and adverse neonatal environments has been linked to alterations in developmental programming and health consequences in offspring. A programmed low nephron endowment, among other altered pathways of susceptibility, likely increases the vulnerability to develop chronic kidney disease in later life. Our aim in this scoping review was to identify gaps in the literature by focusing on understanding the association between life-course exposure to psychosocial stress, and the risk of reduced kidney function. A systematic search in four databases (PubMed, ProQuest, Wed of Science, and Scopus) was performed, yielding 609 articles. Following abstract and full-text review, we identified 19 articles meeting our inclusion criteria, reporting associations between different psychosocial stressors and an increase in the prevalence of kidney disease or decline in kidney function, mainly in adulthood. There are a lack of studies that specifically evaluated the association between gestational exposure to psychosocial stress and measures of kidney function or disease in early life, despite the overall evidence consistent with the independent effects of prenatal stress on other perinatal and postnatal outcomes. Further research will establish epidemiological studies with clear and more comparable psychosocial stressors to solve this critical research gap.

Neighborhood Socioeconomic Status and Identification of Patients With CKD Using Electronic Health Records

RATIONALE & OBJECTIVE

Screening for chronic kidney disease (CKD) is recommended for patients with diabetes and hypertension as stated by the respective professional societies. However, CKD, a silent disease usually detected at later stages, is associated with low socioeconomic status (SES). We assessed whether adding census tract SES status to the standard screening approach improves our ability to identify patients with CKD.

STUDY DESIGN

Screening test analysis.

SETTINGS & PARTICIPANTS

Electronic health records (EHR) of 256,162 patients seen at a health care system in the 7-county Minneapolis/St. Paul area and linked census tract data.

EXPOSURE

The first quartile of census tract SES (median value of owner-occupied housing units <$165,200; average household income <$35,935; percentage of residents >25 years of age with a bachelor's degree or higher <20.4%), hypertension, and diabetes.

OUTCOMES

CKD (eGFR <60 mL/min/1.73 m², or urinary albumin-creatinine ratio >30mg/g, or urinary protein-creatinine ratio >150mg/g, or urinary analysis [albuminuria] >30 mg/d).

ANALYTICAL APPROACH

Sensitivity, specificity, and number needed to screen (NNS) to detect CKD if we screened patients who had hypertension and/or diabetes and/or who lived in low-SES tracts (belonging to the first quartile of any of the 3 measures of tract SES) versus the standard approach.

RESULTS

CKD was prevalent in 13% of our cohort. Sensitivity, specificity, and NNS of detecting CKD after adding tract SES to the screening approach were 67% (95% CI, 66.2%-67.2%), 61% (95% CI, 61.1%-61.5%), and 5, respectively. With the standard approach, sensitivity of detecting CKD was 60% (95% CI, 59.4%-60.4%), specificity was 73% (95% CI, 72.4%-72.7%), and NNS was 4.

LIMITATIONS

One health care system and selection bias.

CONCLUSIONS

Leveraging patients' addresses from the EHR and adding tract-level SES to the standard screening approach modestly increases the sensitivity of detecting patients with CKD at a cost of decreased specificity. Identifying further factors that improve CKD detection at an early stage are needed to slow the progression of CKD and prevent cardiovascular complications.

Neighborhood Socioeconomic Status, Health Insurance, and CKD Prevalence: Findings From a Large Health Care System

RATIONAL & OBJECTIVE

Neighborhood socioeconomic status (SES) and health insurance status may be important upstream social determinants of chronic kidney disease (CKD), but their relationship remains unclear. The aim of this study was to determine whether neighborhood SES and individual-level health insurance status were independently associated with CKD prevalence.

STUDY DESIGN

Observational study using electronic health records (EHRs).

SETTING & PARTICIPANTS

EHRs of patients (n = 185,269) seen at a health care system in the 7-county Minneapolis/St Paul area (2017-2018).

EXPOSURES

Census tract neighborhood SES measures (median value of owner-occupied housing units [wealth], percentage of residents aged >25 years with bachelor's degree or higher [education]) and individual-level health insurance status (aged <65 years: Medicaid vs other insurance; ≥65 years: Medicare vs Medicare and supplemental insurance plan) were obtained from the American Community Survey and EHR data. Neighborhood SES was operationalized into quartiles, comparing low (first quartile) versus high (fourth quartile) neighborhood SES.

OUTCOMES

CKD prevalence: estimated glomerular filtration rate < 60 mL/min/1.73 m2 or proteinuria.

ANALYTIC APPROACH

Multilevel Poisson regression with robust error variance with a random intercept at the census-tract level, adjusted for demographic and clinical covariates, was used to estimate the association between neighborhood SES, insurance, and CKD.

RESULTS

Neighborhood SES and insurance were independently associated with CKD prevalence. In covariate-adjusted models, patients living in low versus high neighborhood SES had a higher CKD prevalence among both younger and older patients. For example, the prevalence ratios of CKD in low versus high neighborhood SES as defined by education among patients younger than 65 and 65 years and older were 1.11 (95% CI, 1.05-1.18) and 1.08 (95% CI, 1.04-1.12), respectively. Patients younger than 65 years receiving Medicaid had higher CKD prevalence versus those with other insurance (1.51 [95% CI, 1.43-1.6]). For patients 65 years and older, insurance was not associated with prevalence of CKD in the fully adjusted model.

LIMITATIONS

One health care system and selection bias.

CONCLUSIONS

Living in low neighborhood SES as defined by wealth and education and having Medicaid for patients younger than 65 years were associated with higher CKD prevalence.

Impact of educational level on incident chronic kidney disease during 13 years of follow-up: a prospective cohort study

OBJECTIVES

To examine the association between educational level and chronic kidney disease (CKD) among the Iranian population.

STUDY DESIGN

This is a prospective cohort study conducted in the framework of the Tehran Lipid and Glucose Study.

METHODS

A total of 8173 Iranians (men = 3659) aged ≥20 years were included in the study. CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². The association between educational status and CKD was explored using multivariate Cox proportional regression analyses, adjusted for age, gender, current smoking, marital status, body mass index, waist circumference, baseline eGFR, diabetes, hypertension, physical activity, history of cardiovascular diseases and dyslipidaemia.

RESULTS

During a median follow-up of 13.14 years, 2609 cases of incident CKD were identified; the corresponding incidence rate was 26.35 (range 25.39-27.34) per 1000 person-years. Compared to low educational level, middle and high educational levels showed lower risks for incident CKD in the crude model [hazard ratio (HR) 0.37 (95% confidence interval {CI} 0.34-0.40) and HR 0.40 (95% CI 0.35-0.45), respectively]; however, these HRs changed direction after further adjustment for age and gender [HR 1.26 (95% CI 1.14-1.39) and HR 1.40 (95% CI 1.22-1.61), respectively]. The increased risk of incident CKD for those at higher educational levels remained significant in the fully adjusted model. In addition, results from the gender stratified analyses were in the same direction as those found among the whole study population (P-value for interaction of gender and education >0.8).

CONCLUSIONS

Higher educational levels were associated with incident CKD during more than a decade of follow-up; this finding may be attributed to unhealthy lifestyle behaviours among this population group.

Neighborhood context and kidney disease in Philadelphia

Neighborhood context might influence the risk of chronic kidney disease (CKD), a condition that impacts approximately 10% of the United States population and is associated with significant morbidity, mortality, and costs. We included a sample of 23,692 individuals in Philadelphia, Pennsylvania, who were seen in a large academic primary care practice between January 1, 2016 and December 31, 2017. We used generalized linear equations to estimate the associations between indicators of neighborhood context (e.g., proximity to healthy foods stores, neighborhood walkability, social capital, crime rate, socioeconomic status) and CKD, adjusted for age, sex, race/ethnicity, and insurance coverage. Among those with CKD, secondary outcomes were poor glycemic control (hemoglobin A1c ≥ 6.5%) and uncontrolled blood pressure (systolic ≥ 140 mm Hg and/or diastolic ≥ 90 mm Hg). The cohort represented residents from 97% of Philadelphia census tracts. CKD prevalence was 10%. When all neighborhood context metrics were considered collectively, only lower neighborhood socioeconomic index (a composite assessment of neighborhood income, educational attainment, and occupation) was associated with a higher risk of CKD (lowest tertile vs. highest tertile: adjusted relative risk [aRR] 1.46 [1.25, 1.69]; mid-tertile vs. highest-tertile: aRR 1.35 [1.25, 1.52]). Among those with CKD, compared to residence in the most walkable neighborhoods (i.e., where most essential resources are accessible by foot), residence in neighborhoods with mid-level WalkScore® (i.e., where only some essential neighborhood resources are accessible by foot) was independently associated with poor glycemic control (aRR 1.20, 95% CI 1.01-1.42). These findings suggest a potential role for measures of neighborhood socioeconomic status in identifying communities that would benefit from screening and treatment for CKD. Studies are also needed to determine mechanisms to explain why residence in neighborhoods not easily navigated by foot or car might hinder glycemic control among people with CKD.

Risk Factors for Incident Kidney Disease in Older Adults: an Australian Prospective Population-Based Study

BACKGROUND

We aimed to determine risk factors for incident CKD in a large population-based cohort.

METHODS

This prospective opt-in population-based cohort study is based on the 45 and Up Study, where New South Wales residents aged ≥45 years were randomly sampled from the Services Australia enrolment database and agreed to complete the 45 and Up Study baseline questionnaire and have their responses linked to their health data in routinely-collected databases. The primary outcome was the development of incident CKD, defined as eGFR<60ml/min/1.73m² . CKD incidence was calculated using Poisson regression. Risk factors for incident CKD were assessed using Cox regression in multivariable models.

RESULTS

In 39,574 participants who did not have CKD at enrolment, independent factors associated with developing CKD included: older age, regional residence (HR 1.38 [1.27-1.50] for outer regional versus major city), smoking (1.13 [1.00-1.27] for current smoker versus non-smoker), obesity (1.25 [1.16-1.35] for obese versus normal body mass index), diabetes mellitus (1.41 [1.33-1.50]), hypertension (1.53 [1.44-1.62]), coronary heart disease (1.13 [1.07-1.20]), depression/anxiety (1.16 [1.09-1.24]), and cancer (1.29 [1.20-1.39]). Migrants were less likely to develop CKD compared with people born in Australia (0.88 [0.83-0.94]). Gender, partner status and socioeconomic factors were not independently associated with developing CKD.

CONCLUSIONS

This large population-based study found multiple modifiable and non-modifiable factors were independently associated with developing CKD. In the Australian setting, the risk of CKD was higher with regional residence. Differences according to socioeconomic status were predominantly explained by age, comorbidities and harmful health-related behaviours This article is protected by copyright. All rights reserved.

Understanding the Link between Neighborhoods and Kidney Disease

Neighborhoods are where we live, learn, work, pray, and play. Growing evidence indicates that neighborhoods are an important determinant of health. The built features of our neighborhoods, such as the ways in which the streets are designed and connected and the availability of green spaces and transit stops, as well as the social features, such as the trust among neighbors and the perceptions of safety, may influence health through multiple pathways, such as access to important resources, psychosocial stress, and health behaviors. In particular, the extant literature consistently documents an association between neighborhood features and renal-associated conditions, such as cardiovascular disease, hypertension, diabetes, and obesity. There is also some evidence suggesting an association between neighborhood poverty and ESKD. The link between neighborhood and earlier stages of CKD, however, has been less clear, with most studies documenting no association. It may be that the neighborhood measures used in previous studies do not capture features of the neighborhood important for earlier stages of disease development and progression. It may also be that our current biomarkers (e.g., eGFR) and urine protein are not able to pick up very early forms of renal damage because of the kidney's overall high reserve capacity. This paper critically reviews the state of the literature on neighborhood and renal disease, with recommendations for neighborhood measures in future research. Neighborhoods are designed, built, and informed by policy, and thus, they are amenable to intervention, making them a potentially powerful way to improve renal health and reduce health inequalities at the population level.

Survival of the Fittest: Addressing the Disparities in the Burden of Chronic Kidney Disease

The prevalence of chronic kidney disease (CKD) is increasingly becoming recognized as a global health concern as well as a critical determinant of poor health outcomes. Decreased access to health care and low socioeconomic status (SES) worsen the adverse effects of biologic or genetic predisposition to CKD. All the studies used were retrieved using the PubMed database. The literature suggests that in developing and developed countries, lower SES is inversely proportional to CKD. It shows an inconsistent relationship between CKD and race; that is, there may or may not be a relationship between these two variables. In the United States (US), the prevalence of the early stages of CKD is similar across different racial/ethnic groups. However, the preponderance of end-stage renal disease (ESRD) is higher for minorities than their non-Hispanic white counterparts.

Further investigation is required to understand the role of racial disparities and CKD as well as to understand the significant difference seen in the incidence when progressing from CKD to ESRD. It is necessary to recognize how lower SES and racial/ethnic disparity may result in the impediment of appropriate disease management. A possible approach is the use of the biopsychosocial model, which integrates biological, individual, and neighborhood factors. A practical method of providing appropriate care to these populations will require economically feasible prevention strategies as well as extending the scope of dialysis by the implementation of cheaper alternatives.

Socioeconomic Position and Incidence of Glomerular Diseases

BACKGROUND AND OBJECTIVES

Social deprivation is a recognized risk factor for undifferentiated CKD; however, its association with glomerular disease is less well understood. We sought to investigate the relationship between socioeconomic position and the population-level incidence of biopsy-proven glomerular diseases.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this retrospective cohort study, a provincial kidney pathology database (2000-2012) was used to capture all incident cases of membranous nephropathy (n=392), IgA nephropathy (n=818), FSGS (n=375), ANCA-related GN (ANCA-GN, n=387), and lupus nephritis (n=389) in British Columbia, Canada. Quintiles of area-level household income were used as a proxy for socioeconomic position, accounting for regional differences in living costs. Incidence rates were direct standardized to the provincial population using census data for age and sex and were used to generate standardized rate ratios. For lupus nephritis, age standardization was performed separately in men and women.

RESULTS

A graded increase in standardized incidence with lower income was observed for lupus nephritis (P<0.001 for trend in both sexes) and ANCA-GN (P=0.04 for trend). For example, compared with the highest quintile, the lowest income quintile had a standardized rate ratio of 1.7 (95% confidence interval, 1.19 to 2.42) in women with lupus nephritis and a standardized rate ratio of 1.5 (95% confidence interval, 1.09 to 2.06) in ANCA-GN. The association between income and FSGS was less consistent, in that only the lowest income quintile was associated with a higher incidence of disease (standardized rate ratio, 1.55; 95% confidence interval, 1.13 to 2.13). No significant associations were demonstrated for IgA nephropathy or membranous nephropathy.

CONCLUSIONS

Using population-level data and a centralized pathology database, we observed an inverse association between socioeconomic position and the standardized incidence of lupus nephritis and ANCA-GN.

Life Course Socioeconomic Status, Allostatic Load, and Kidney Health in Black Americans

BACKGROUND AND OBJECTIVES

Low socioeconomic status confers unfavorable health, but the degree and mechanisms by which life course socioeconomic status affects kidney health is unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined the association between cumulative lifetime socioeconomic status and CKD in black Americans in the Jackson Heart Study. We used conditional process analysis to evaluate allostatic load as a potential mediator of this relation. Cumulative lifetime socioeconomic status was an age-standardized z-score, which has 1-SD units by definition, and derived from self-reported childhood socioeconomic status, education, and income at baseline. Allostatic load encompassed 11 baseline biomarkers subsuming neuroendocrine, metabolic, autonomic, and immune physiologic systems. CKD outcomes included prevalent CKD at baseline and eGFR decline and incident CKD over follow-up.

RESULTS

Among 3421 participants at baseline (mean age 55 years [SD 13]; 63% female), cumulative lifetime socioeconomic status ranged from -3.3 to 2.3, and 673 (20%) had prevalent CKD. After multivariable adjustment, lower cumulative lifetime socioeconomic status was associated with greater prevalence of CKD both directly (odds ratio [OR], 1.18; 95% confidence interval [95% CI], 1.04 to 1.33 per 1 SD and OR, 1.45; 95% CI, 1.15 to 1.83 in lowest versus highest tertile) and via higher allostatic load (OR, 1.09; 95% CI, 1.06 to 1.12 per 1 SD and OR, 1.17; 95% CI, 1.11 to 1.24 in lowest versus highest tertile). After a median follow-up of 8 years (interquartile range, 7-8 years), mean annual eGFR decline was 1 ml/min per 1.73 m² (SD 2), and 254 out of 2043 (12%) participants developed incident CKD. Lower cumulative lifetime socioeconomic status was only indirectly associated with greater CKD incidence (OR, 1.04; 95% CI, 1.01 to 1.07 per 1 SD and OR, 1.08; 95% CI, 1.02 to 1.14 in lowest versus highest tertile) and modestly faster annual eGFR decline, in milliliters per minute (OR, 0.01; 95% CI, 0.00 to 0.02 per 1 SD and OR, 0.02; 95% CI, 0.00 to 0.04 in lowest versus highest tertile), via higher baseline allostatic load.

CONCLUSIONS

Lower cumulative lifetime socioeconomic status was substantially associated with CKD prevalence but modestly with CKD incidence and eGFR decline via baseline allostatic load.

Cross-sectional study of association between psychosocial stressors with chronic kidney disease among migrant and non-migrant Ghanaians living in Europe and Ghana: the RODAM study

OBJECTIVES

The association between psychosocial stressors (PS) and chronic kidney disease (CKD) among sub-Saharan African (SSA) populations is unknown. We examined the association between PS and CKD prevalence among rural and urban Ghanaians and Ghanaian migrants living in three European cities. We also assessed if the influence of PS on CKD is partially mediated by primary risk factors (hypertension and diabetes) of CKD.

DESIGN

A multi-centred cross sectional data from the Research on Obesity and Diabetes among African Migrants study.

SETTING

Rural and urban Ghana and three European cities (Amsterdam, Berlin and London).

PARTICIPANTS

A random sample of 5659 adults (Europe 3167, rural Ghana 1043 and urban Ghana 1449) aged 25-70 years.

EXPLANATORY MEASURES

PS defined by negative life events, perceived discrimination, perceived stress at work/home and depressive symptoms. Three CKD outcomes were considered using the 2012 Kidney Disease: Improving Global Outcomes severity of CKD classification. Comparisons between PS and CKD outcomes were made using logistic regression analyses across all sites.

RESULTS

We observed higher proportion of negative life events (68.7%) and perceived permanent stress (15.9%) among Ghanaians living in Ghana than Ghanaians living in Europe. Depressive symptoms (7.5%) and perceived discrimination (29.7%) were more common among Ghanaians living in Europe than Ghanaians living in Ghana. No significant association was observed between any of the PS constructs and CKD outcomes across sites except for positive association between stress at work/home and albuminuria (2.81, 95% CI 1.46 to 5.40) and CKD risk (2.78, 95% CI 1.43 to 5.43) among Ghanaians living in Berlin.

CONCLUSION

Our study found a positive association between stress at work/home and albuminuria and CKD risk. There was no convincing evidence of associations between the other PS constructs and the prevalence of CKD risk. Further studies are needed to identify potential factors driving the high prevalence of CKD among these populations.

Periodontal Disease Assessed Using Clinical Dental Measurements and Cancer Risk in the ARIC Study

Background

While evidence is increasingly consistent with a positive association between periodontitis and cancer risk, most studies have relied on self-reported periodontitis. In this study, we prospectively evaluated the association of periodontal disease severity with cancer risk in black and white older adults in a cohort study that included a dental examination.

Methods

Included were 7466 participants in the Atherosclerosis Risk in Communities study cohort who at visit 4 (1996-1998) reported being edentulous or underwent the dental examination. Probing depth and gingival recession were measured at six sites on all teeth; these measurements were used to define periodontal disease severity. Incident cancers (n = 1648) and cancer deaths (n = 547) were ascertained during a median of 14.7 years of follow-up. All statistical tests were two-sided.

Results

An increased risk of total cancer (hazard ratio [HR] = 1.24, 95% confidence interval [CI] = 1.07 to 1.44, Ptrend = .004) was observed for severe periodontitis (>30% of sites with attachment loss >3 mm) compared with no/mild periodontitis (<10% of sites with attachment loss >3 mm), adjusting for smoking and other factors. Strong associations were observed for lung cancer (HR = 2.33, 95% CI = 1.51 to 3.60, Ptrend < .001), and elevated risks were noted for colorectal cancer for severe periodontitis, which were significant among never smokers (HR = 2.12, 95% CI = 1.00 to 4.47). Associations were generally weaker, or not apparent among black participants, except for lung and colorectal cancers, where associations were similar by race. No associations were observed for breast, prostate, or hematopoietic and lymphatic cancer risk.

Conclusions

This study provides additional evidence that cancer risk, especially for lung and colorectal cancer, is elevated in individuals with periodontitis. Additional research is needed to understand cancer site-specific and racial differences in findings.

Cross-sectional study of association between socioeconomic indicators and chronic kidney disease in rural-urban Ghana: the RODAM study

OBJECTIVES

Studies from high-income countries suggest higher prevalence of chronic kidney disease (CKD) among individuals in low socioeconomic groups. However, some studies from low/middle-income countries show the reverse pattern among those in high socioeconomic groups. It is unknown which pattern applies to individuals living in rural and urban Ghana. We assessed the association between socioeconomic status (SES) indicators and CKD in rural and urban Ghana and to what extent the higher SES of people in urban areas of Ghana could account for differences in CKD between rural and urban populations.

SETTING

The study was conducted in Ghana (Ashanti region). We used baseline data from a multicentre Research on Obesity and Diabetes among African Migrants (RODAM) study.

PARTICIPANTS

The sample consisted of 2492 adults (Rural Ghana, 1043, Urban Ghana, 1449) aged 25-70 years living in Ghana.

EXPOSURE

Educational level, occupational level and wealth index.

OUTCOME

Three CKD outcomes were considered using the 2012 Kidney Disease: Improving Global Outcomes severity of CKD classification: albuminuria, reduced glomerular filtration rate and high to very high CKD risk based on the combination of these two.

RESULTS

All three SES indicators were not associated with CKD in both rural and urban Ghana after age and sex adjustment except for rural Ghana where high wealth index was significantly associated with higher odds of reduced estimated glomerular filtration rate (eGFR) (adjusted OR, 2.38; 95% CI 1.03 to 5.47). The higher rate of CKD observed in urban Ghana was not explained by the higher SES of that population.

CONCLUSION

SES indicators were not associated with prevalence of CKD except for wealth index and reduced eGFR in rural Ghana. Consequently, the higher SES of urban Ghana did not account for the increased rate of CKD among urban dwellers suggesting the need to identify other factors that may be driving this.

Socioeconomic disadvantage and the risk of advanced chronic kidney disease: results from a cohort study with 1.4 million participants

Background

Several studies have investigated the effect of socioeconomic deprivation on cardiovascular disease (CVD) and diabetes; less is known about its effect on chronic kidney disease (CKD). We aimed to measure the association between deprivation, CKD Stages 4–5 and end-stage renal disease (ESRD) in a general population sample.

Methods

This observational study examined 1 405 016 participants from the English Clinical Practice Research Datalink (2000–14), linked to hospital discharge data and death certification. Deprivation was assessed according to the participant’s postcode. Cox models were used to estimate hazard ratios (HRs) for CKD Stages 4–5 and ESRD, adjusting for age and sex, and additionally for smoking status, body mass index, diabetes, systolic blood pressure, prior CVD and estimated glomerular filtration rate (eGFR) at baseline.

Results

During 7.5 years of median follow-up, 11 490 individuals developed CKD Stages 4–5 and 1068 initiated ESRD. After adjustment for age and sex, the HRs and confidence interval (CI) comparing those in the 20% most deprived of the population to the 20% least deprived were 1.76 (95% CI 1.68–1.84) and 1.82 (95% CI 1.56–2.12) for CKD Stages 4–5 and ESRD, respectively. Further adjustment for known risk factors and eGFR substantially attenuated these HRs. Adding our results to all known cohort studies produced a pooled relative risk of 1.61 (95% CI 1.42–1.83) for ESRD, for comparisons between highest to lowest categories of deprivation.

Conclusion

Socioeconomic deprivation is independently associated with an increased hazard of CKD Stages 4–5 and ESRD, but in large part may be mediated by known risk factors.

Neighborhood Social Context and Kidney Function Over Time: The Multi-Ethnic Study of Atherosclerosis

RATIONALE & OBJECTIVE

Although socioeconomic status has been associated with chronic kidney disease (CKD), little is known about its relationship to residential neighborhood context.

STUDY DESIGN

Secondary analysis of the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort study designed to investigate the development and progression of subclinical cardiovascular disease.

SETTING & PARTICIPANTS

6,814 men and women who were between 45 and 84 years of age and free of cardiovascular disease were recruited between 2000 and 2002 from Baltimore, MD; Chicago, IL; Forsyth County, NC; Los Angeles, CA; New York, NY; and St. Paul, MN.

EXPOSURES

A composite neighborhood problem score (calculated based on 7 participant-reported domains at study entry: adequacy of food sources, availability of parks/playground, noise, sidewalks, traffic, trash and litter, and violence) and a social cohesion score (calculated based on 5 participant-reported attributes of people in their neighborhood: close knit; get along; willing to help neighbors; trustworthy; and share values).

OUTCOMES

Estimated glomerular filtration rate (eGFR; calculated using the CKD-EPI [CKD Epidemiology Collaboration] creatinine-cystatin C equation) and an indicator of eGFR decline > 30% since study entry using follow-up eGFR quantified at 4 examinations: 2000 to 2002, 2004 to 2005, 2005 to 2007, and 2010 to 2011.

ANALYTICAL APPROACH

Associations between each neighborhood measure (in separate models) and eGFR decline > 30% from baseline and annualized eGFR change were estimated using Cox proportional hazards and linear mixed regression models, respectively, adjusting for potential confounders.

RESULTS

While neighborhood social context differs by race/ethnicity, neither neighborhood problems nor social cohesion was independently associated with eGFR decline after adjustment for confounders.

LIMITATIONS

Incomplete capture of the early stages of eGFR decline, reliance on observational data, limited variation in neighborhood measures, and the potential for residual confounding.

CONCLUSIONS

Although we showed no independent association between neighborhood context and eGFR decline, it is associated with many CKD risk factors and further work is needed to clarify whether it has an independent role in CKD.

Kidney Disease in Women is Associated with Disadvantaged Childhood Socioeconomic Position

BACKGROUND

Socioeconomic position (SEP) is an important determinant of health and it is dynamic across the entire lifespan. We sought to investigate the relationship between life-course SEP and chronic kidney disease (CKD) using 3 conceptual models: critical period, pathway and accumulation.

METHODS

Cross-sectional analysis of 4,996 participants from The Irish Longitudinal Study on Ageing, a nationally representative cohort of community-dwelling adults aged ≥50 years. We defined childhood and adulthood SEP according to father's and respondent's occupation respectively. SEP was categorised as high (reference), intermediate, low and never worked. CKD was defined as a glomerular filtration rate < 60 mL/min/1.73 m2 estimated from the combination of creatinine and cystatin C. We used logistic regression to estimate the age-adjusted association between SEP and CKD separately in men and women.

RESULTS

Low childhood SEP was strongly associated with CKD in women, after adjusting for adulthood SEP (OR 1.90 [95% CI 1.24-2.92]), supporting the critical period hypothesis. This association was not explained by traditional CKD risk factors. Women who experienced low childhood SEP and whose circumstances improved in adulthood also had increased odds of CKD, further supporting a critical period effect in childhood. There was comparatively less evidence in support of the pathway or accumulation models. We did not observe a statistically significant association between SEP and CKD in men.

CONCLUSIONS

Our findings suggest that women exposed to disadvantaged SEP in childhood represent an at-risk group in whom there may be opportunities for identification of CKD and facilitation of health-promoting behaviours from an early age.

eMAP:CKD: electronic diagnosis and management assistance to primary care in chronic kidney disease

Background

The increasing burden of chronic kidney disease (CKD) underpins the importance for improved early detection and management programs in primary care to delay disease progression and reduce mortality rates. eMAP:CKD is a pilot program for primary care aimed at addressing the gap between current and best practice care for CKD.

Methods

Customized software programs were developed to integrate with primary care electronic health records (EHRs), allowing real-time prompting for CKD risk factor identification, testing, diagnosis and management according to Kidney Health Australia's (KHA) best practice recommendations. Primary care practices also received support from a visiting CKD nurse and education modules. Patient data were analyzed at baseline (150 910 patients) and at 15 months (175 917 patients) following the implementation of the program across 21 primary care practices.

Results

There was improvement in CKD risk factor recognition (29.40 versus 33.84%; P < 0.001) and more complete kidney health tests were performed (3.20 versus 4.30%; P < 0.001). There were more CKD diagnoses entered into the EHR (0.48 versus 1.55%; P < 0.001) and more patients achieved KHA's recommended management targets (P < 0.001).

Conclusion

The eMAP:CKD program has shown an improvement in identification of patients at risk of CKD, appropriate testing and management of these patients, as well as increased documentation of CKD diagnosis entered into the EHRs. We have demonstrated efficacy in overcoming the verified gap between current and best practice in primary care. The success of the pilot program has encouraging implications for use across the primary care community as a whole.

SES, Chronic Kidney Disease, and Race in the U.S.: A Systematic Review and Meta-analysis

CONTEXT

The risk of chronic kidney disease (CKD) in the U.S. is higher in individuals with low SES than in those with high SES. However, differences in these risks between African Americans and whites are unclear.

EVIDENCE ACQUISITION

Studies published through August 30, 2016 in Medline and EMBASE were searched. From the seven studies (1,775,267 participants) that met inclusion criteria, association estimates were pooled by race in meta-analysis. The ratio of association estimates and the corresponding 95% CIs for African Americans and whites were also pooled in meta-analysis. Additionally, meta-regression analysis was used to explore whether race is related to the strength of SES-CKD association. The analysis was conducted in September 2016.

EVIDENCE SYNTHESIS

The risk of CKD in low-SES people was 58% higher in African Americans (relative risk=1.58, 95% CI=1.33, 1.84) and 91% higher in whites (relative risk=1.91, 95% CI=1.47, 2.35) compared with their high-SES counterparts. The relative risk of CKD in low SES (versus high SES) was lower in African Americans than in whites (relative risk ratio=0.71, 95% CI=0.65, 0.77). Results from meta-regression analyses also indicated that race is potentially related to the strength of the association between low SES and CKD (p for difference between whites and African Americans=0.001).

CONCLUSIONS

The risk of CKD in low SES (versus high SES) is higher in whites than in African Americans.

Maternal determinants of renal mass and function in the fetus and neonate

The impact of adverse maternal and early gestational issues, ranging from maternal-fetal interactions all the way through to premature birth, are recognized as having influence on the subsequent development of chronic diseases later in life. The development of chronic kidney disease (CKD) as a direct result of early life renal injury or a sequela of diseases such as hypertension or diabetes is a good model example of the potential impact that early life events may have on renal development and lifelong function. The global monetary and human resource cost of CKD is exorbitant. Socio-economic factors, along with other factors (genetic and environmental) may significantly influence the timing and display of phenotypic expression in fetuses and neonates at risk for developing CKD, yet very few of these factors are studied or well understood. In general our focus has been directed at treatment once CKD is established. This strategy has been and remains short-sighted and costly. Earlier understanding of the intrauterine determinants of renal mass development (i.e. environmental "biomes", poor maternal-fetal health, socio-economic factors impacting early life events, diet, access to value based health care and educational opportunities on disease evolution) may allow us an opportunity for earlier intervention. This article aims to provide some foundation for improved understanding of the maternal determinants of renal mass and function in the fetus and neonate.

Social Determinants of Racial Disparities in CKD

Significant disparities in CKD rates and outcomes exist between black and white Americans. Health disparities are defined as health differences that adversely affect disadvantaged populations, on the basis of one or more health outcomes. CKD is the complex result of genetic and environmental factors, reflecting the balance of nature and nurture. Social determinants of health have an important role as environmental components, especially for black populations, who are disproportionately disadvantaged. Understanding the social determinants of health and appreciating the underlying differences associated with meaningful clinical outcomes may help nephrologists treat all their patients with CKD in an optimal manner. Altering the social determinants of health, although difficult, may embody important policy and research efforts, with the ultimate goal of improving outcomes for patients with kidney diseases, and minimizing the disparities between groups.

Effects of socioeconomic status on physical and mental health of hemodialysis patients in Japan: differences by age, period, and cohort

Study purpose

Whether or not socioeconomic status (SES)-related differences in the health of hemodialysis patients differ by age, period, and birth cohort remains unclear. We examined whether SES-related gaps in physical and mental health change with age, period, and birth cohort for hemodialysis patients.

Methods

Data were obtained from repeated cross-sectional surveys conducted in 1996, 2001, 2006, and 2011, with members of a national patients’ association as participants. We used raking adjustment to create a database which had similar characteristics to the total sample of dialysis patients in Japan. SES was assessed using family size-adjusted income levels. We divided patients into three groups based on their income levels: below the first quartile, over the second quartile and under the third quartile, and over the fourth quartile. We used the number of dialysis complications as a physical health indicator and depressive symptoms as a mental health indicator. We used a cross-classified random-effects model that estimated fixed effects of age categories and period as level-1 factors, and random effects of birth cohort as level-2 factors.

Results

Relative risk of dialysis complications in respondents below the first quartile compared with ones over the fourth quartile was reduced in age categories >60 years. Mean differences in depressive symptoms between respondents below the first quartile and ones over the fourth quartile peaked in the 50- to 59-year-old age group, and were reduced in age groups >60 years. In addition, mean differences varied across periods, widening from 1996 to 2006. There were no significant birth cohort effects on income differences for dialysis complications or depressive symptoms.

Conclusion

The number of dialysis complications and depressive symptoms in dialysis patients were affected by income differences, and the degree of these differences changed with age category and period.

Matching the Genotype in Resolution: Innovative Ways of Phenotype Capture

Social and spatial context are important determinants of morbidity and mortality. However, there is little clarity about the role of context for kidney disease specifically, particularly before the end stage. Meanwhile, research clarifying the clinical, cellular, molecular, and genetic causes of kidney disease is accelerating considerably. We postulate that without contextual information, even the most detailed biomedical information cannot fully capture the factors that ultimately drive the development and progression of kidney disease. The Nephrotic Syndrome Study Network is integrating detailed, state-of-the-art information on a social and spatial context to enable the exploration of the associations between the social environment and kidney disease. Here, we discuss the extant literature on social context and kidney disease, present information on sources of contextual information, and provide recommended further reading to facilitate future research on the contribution of the social context to kidney disease.

Estimating the glomerular filtration rate in the Spanish working population: chronic kidney disease prevalence and its association with risk factors

OBJECTIVE

This study aims to investigate the influence of estimated glomerular filtration rate (eGFR) with two equations (and by one or two separate measurements), on the prevalence of chronic kidney disease (CKD) and its association with blood pressure, and cardiovascular and metabolic risk factors.

METHODS

Between January 2010 and October 2011, the Ibermutuamur CArdiovascular RIsk Assessment project included 128 588 workers (77.2% men, mean age 39.3 years, range 16-75), who underwent two consecutive yearly medical check-ups and had information for eGFR according to the MDRD-IDMS and CKD-EPI equations (serum creatinine was measured by a isotope-dilution mass spectrometry traceable method in a single central laboratory). CKD was defined by an eGFR less than 60 ml/min per 1.73 m. Subclinical (occult) renal disease was defined as an eGFR less than 60 ml/min per 1.73 m in patients with serum creatinine below 1.3 mg/dl and below 1.2 mg/dl in men and women, respectively.

RESULTS

In this working population, prevalence of CKD was very low, but two to six times lower when two separate eGFRs below 60 ml/min per 1.73 m were used. The prevalence of CKD was significantly lower with the CKD-EPI compared to the MDRD-IDMS equation. The same applies to occult CKD. In male workers, occult CKD was practically nonexistent.Multivariate analyses show that blood pressure, total serum cholesterol, and serum glucose (positively), and high-density lipoprotein and low-density lipoprotein (negatively) were associated with CKD, with both equations. Another metabolic factor (waist circumference) was only associated (positively) with CKD defined by the CKD-EPI equation, which appears to be associated with most components of the metabolic syndrome.

CONCLUSIONS

The CKD-EPI formula, calculated on the basis of two reported blood samples, may provide the most specific definition of CKD.

Food Access, Chronic Kidney Disease, and Hypertension in the U.S

INTRODUCTION

Greater distance to full-service supermarkets and low income may impair access to healthy diets and contribute to chronic kidney disease (CKD) and hypertension. The study aim was to determine relationships among residence in a "food desert," low income, CKD, and blood pressure.

METHODS

Adults in the 2003-2010 National Health and Nutrition Examination Survey (N=22,173) were linked to food desert data (www.ers.usda.gov) by Census Tracts. Food deserts have low median income and are further from a supermarket or large grocery store (>1 mile in urban areas, >10 miles in rural areas). Weighted regression was used to determine the association of residence in a food desert and family income with dietary intake; systolic blood pressure (SBP); and odds of CKD. Data analysis was performed in 2014-2015.

RESULTS

Compared with those not in food deserts, participants residing in food deserts had lower levels of serum carotenoids (p<0.01), a biomarker of fruit and vegetable intake, and higher SBP (1.53 mmHg higher, 95% CI=0.41, 2.66) after adjustment for demographics and income. Residence in a food desert was not associated with odds of CKD (OR=1.20, 95% CI=0.96, 1.49). Lower, versus higher, income was associated with lower serum carotenoids (p<0.01) and higher SBP (2.00 mmHg higher for income-poverty ratio ≤1 vs >3, 95% CI=1.12, 2.89), but also greater odds of CKD (OR=1.76 for income-poverty ratio ≤1 vs >3, 95% CI=1.48, 2.10).

CONCLUSIONS

Limited access to healthy food due to geographic or financial barriers could be targeted for prevention of CKD and hypertension.

Serum phosphate and social deprivation independently predict all-cause mortality in chronic kidney disease

Background

Hyperphosphataemia is linked to cardiovascular disease and mortality in chronic kidney disease (CKD). Outcome in CKD is also affected by socioeconomic status. The objective of this study was to assess the associations between serum phosphate, multiple deprivation and outcome in CKD patients.

Methods

All adult patients currently not on renal replacement therapy (RRT), with first time attendance to the renal outpatient clinics in the Glasgow area between July 2010 and June 2014, were included in this prospective study. Area socioeconomic status was assessed as quintiles of the Scottish Index of Multiple Deprivation (SIMD). Outcomes were all-cause and cardiovascular mortality and commencement of RRT.

Results

The cohort included 2950 patients with a median (interquartile range) age 67.6 (53.6–76.9) years. Median (interquartile range) eGFR was 38.1 (26.3–63.5) ml/min/1.73 m², mean (±standard deviation) phosphate was 1.13 (±0.24) mmol/L and 31.6 % belonged to the most deprived quintile (SIMD quintile I). During follow-up 375 patients died and 98 commenced RRT. Phosphate ≥1.50 mmol/L was associated with all-cause (hazard ratio (HR) 2.51; 95 % confidence interval (CI) 1.63-3.89) and cardiovascular (HR 5.05; 95 % CI 1.90–13.46) mortality when compared to phosphate 0.90–1.09 mmol/L in multivariable analyses. SIMD quintile I was independently associated with all-cause mortality. Phosphate did not weaken the association between deprivation index and mortality, and there was no interaction between phosphate and SIMD quintiles. Neither phosphate nor SIMD predicted commencement of RRT.

Conclusions

Multiple deprivation and serum phosphate were strong, independent predictors of all-cause mortality in CKD and showed no interaction. Phosphate also predicted cardiovascular mortality. The results suggest that phosphate lowering should be pursued regardless of socioeconomic status.

Chronic kidney disease among adult participants of the ELSA-Brasil cohort: association with race and socioeconomic position

BACKGROUND

There is increased interest in understanding why chronic kidney disease (CKD) rates vary across races and socioeconomic groups. We investigated the distribution of estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (ACR) and CKD according to these factors in Brazilian adults.

METHODS

Using baseline data (2008-2010) of 14,636 public sector employees (35-74 years) enrolled in the Brazilian Longitudinal Study of Adult Health (ELSA)-Brasil multicentre cohort, we estimated the prevalence of CKD by sex, age, race and socioeconomic factors. CKD was defined as ACR ≥ 30 mg/g and/or eGFR < 60 mL/min/1.73 m(2). GFR was estimated by CKD epidemiology collaboration without correction for race. We used logistic regression to estimate the association of race and socioeconomic position (education, income, social class and occupational nature) with CKD after adjusting for sex, age and several health-related factors.

RESULTS

The prevalence of high ACR or low eGFR, in isolation and combined, increased with age, and was higher in individuals with lower socioeconomic position and among black individuals and indigenous individuals. The overall prevalence of CKD was 8.9%. After full adjustments, it was similar in men and women (OR=0.90; 95% CI 0.79 to 1.02) and increased with age (OR=1.07; 95% CI 1.06 to 1.08). Compared to white individuals, black individuals (OR=1.23; 95% CI 1.03 to 1.47), 'pardos' (OR=1.16; 95% CI 1.00 to 1.35) and Indigenous (OR=1.72; 95% CI 1.07 to 2.76) people had higher odds for CKD. Having high school (OR=1.15; 95% CI 1.00 to 1.34) or elementary education (OR=1.23; 95% CI 1.03 to 1.47) increased the odds for CKD compared to those having a university degree.

CONCLUSIONS

There were marked discrepancies in the increases in reduced eGFR and high ACR with age and race. The higher prevalences of CKD in individuals with lower educational status and in non-whites were not explained by differences in health-related factors.

Serum Phosphorus Levels, Race, and Socioeconomic Status in Incident Hemodialysis Patients

OBJECTIVE

We sought to examine the relationship between race, socioeconomic status, and serum phosphorus levels in patients with end-stage renal disease incident to hemodialysis (HD) at a large, integrated health-care delivery system in Southern California.

DESIGN

Retrospective cohort study.

SUBJECTS

A total of 5,778 adult patients who initiated HD at our institution between January 1, 2007 and June 30, 2013.

MAIN OUTCOME MEASURES

Unadjusted and adjusted time-averaged serum phosphorus levels and actual phosphorus levels over time. Phosphorus levels were also analyzed by repeated measures as a continuous measure and by phosphorus category. Baseline patient covariates included age, self-reported race, gender, cause of end-stage renal disease, and Charlson comorbidity index scores. Education and income level were estimated using geocoded data.

RESULTS

A total of 68,372 phosphorus levels were available for 4,862 patients. Estimated annual family income fell below $40,001 in 66.1% of African Americans (AAs) and 62.7% of Hispanics compared with 43.5% of Asians and 43.7% of whites, P < .0001. Educational level fell into the highest category for whites (70.8%) compared with AA (44.8%) or Hispanic (30.5%) patients, P < .0001. Adjusted time-averaged phosphorus levels were lower among Hispanics (4.33 mg/dL, 95% confidence interval [CI] 4.27-4.40) compared with Asian (4.54 mg/dL, 95% CI 4.45-4.64, P < .001) and white patients (4.48 mg/dL, 95% CI 4.43-4.54, P < .001) but similar to AA patients. Asian patients experienced a significant increase in phosphorus levels over time (0.11 mg/dL per year, P < .0001). There were no significant effects of race, time, or race by time interactions in the unadjusted and adjusted categorical analyses of phosphorus levels.

CONCLUSIONS

Our findings suggest that serum phosphorus levels are similar among HD patients, irrespective of race or socioeconomic status.

Socioeconomic disparities in chronic kidney disease: a systematic review and meta-analysis

CONTEXT

Evidence on the strength of the association between low SES and chronic kidney disease (CKD; measured by low estimated glomerular filtration rate [eGFR], high albuminuria, low eGFR/high albuminuria, and renal failure) is scattered and sometimes conflicting. Therefore, a systematic review and meta-analysis was performed to summarize the strength of the associations between SES and CKD and identify study-level characteristics related to this association.

EVIDENCE ACQUISITION

Studies published through January 2013 in MEDLINE and Embase were searched. From 35 studies that met the inclusion criteria, association estimates were pooled per CKD measure in the meta-analysis (performed between 2013 and 2014). Meta-regression analysis was used to identify study-level characteristics related to the strength of the SES-CKD association.

EVIDENCE SYNTHESIS

Low SES was associated with low eGFR (OR=1.41, 95% CI=1.21, 1.62), high albuminuria (OR=1.52, 95% CI=1.22, 1.82), low eGFR/high albuminuria (OR=1.38, 95% CI=1.03, 1.74), and renal failure (OR=1.55, 95% CI=1.40, 1.71). Differences in SES measures across studies were not related to the strength of associations between low SES and any of the CKD measures (low GFR, p=0.63; high albuminuria, p=0.29; low eGFR/high albuminuria, p=0.54; renal failure, p=0.31). Variations in the strength of associations were related to the level of covariate adjustment for low eGFR (p<0.001) and high albuminuria (p<0.001).

CONCLUSIONS

Socioeconomic disparities in CKD were fairly strong, irrespective of how SES was measured. Variations in the strength of the associations were related to the level of covariate adjustment, particularly for low eGFR and high albuminuria.

Early-life course socioeconomic factors and chronic kidney disease

Kidney failure or ESRD affects approximately 650,000 Americans, whereas the number with earlier stages of CKD is much higher. Although CKD and ESRD are usually associated with adulthood, it is likely that the initial stages of CKD begin early in life. Many of these pathways are associated with low birth weight and disadvantaged socioeconomic status (SES) in childhood, translating childhood risk into later-life CKD and kidney failure. Social factors are thought to be fundamental causes of disease. Although the relationship between adult SES and CKD has been well established, the role of early childhood SES for CKD risk remains obscure. This review provides a rationale for examining the association between early-life SES and CKD. By collecting data on early-life SES and CKD, the interaction with other periods in the life course could also be studied, allowing for examination of whether SES trajectories (eg, poverty followed by affluence) or cumulative burden (eg, poverty at multiple time points) are more relevant to lifetime CKD risk.

Stress and the kidney

The prevalence of CKD has increased considerably over the past 2 decades. The rising rates of CKD have been attributed to known comorbidities such as diabetes, hypertension, and obesity; however, recent research has begun to explore the degree to which social, economic, and psychological factors have implications for the prevalence and progression of CKD, especially among high-risk populations such as African Americans. It has been suggested that stress can have implications for CKD, but this area of research has been largely unexplored. One contributing factor associated with the paucity of research on CKD is that many of the social, psychological, and environmental stressors cannot be recreated or simulated in a laboratory setting. Social science has established that stress can have implications for health, and we believe that stress is an important determinant of the development and progression of CKD. We draw heavily from the social scientific and social epidemiologic literature to present an intersectional conceptual frame specifying how stress can have implications for kidney disease, its progression, and its complications through multiple stressors and pathways.

Socioeconomic factors and racial disparities in kidney disease outcomes

African Americans suffer disproportionately from advanced and progressive chronic kidney disease (CKD). Socioeconomic factors are believed to play an important role in this disparity, and likely influence African Americans' increased risk of CKD through multiple pathways. Low socioeconomic status (SES) may contribute to racial disparities in CKD because of the greater prevalence of poverty, for example, among African Americans as compared with whites. However, low SES has a stronger relation with CKD among African Americans than among whites, underscoring that the context and magnitude of socioeconomic influences on CKD outcomes varies between these populations. These socioeconomic influences may produce new or potentiate existing racial differences in biology. This review discusses what is known about the role of SES in explaining racial disparities in CKD, highlights several knowledge gaps in this area, and suggests future directions toward the elimination of disparities in CKD.

Chronic kidney disease, albuminuria and socioeconomic status in the Health Surveys for England 2009 and 2010

BACKGROUND

Renal replacement therapy rates are inversely related to socioeconomic status (SES) in developed countries. The relationship between chronic kidney disease (CKD) and SES is less clear. This study examined the relationships between SES and CKD and albuminuria in England.

METHODS

Data from the Health Survey for England 2009 and 2010 were combined. The prevalence of CKD 3-5 and albuminuria was calculated, and logistic regression used to determine their association with five individual-level measures and one area-level measure of SES.

RESULTS

The prevalence of CKD 3-5 was 5.2% and albuminuria 8.0%. Age-sex-adjusted CKD 3-5 was associated with lack of qualifications [odds ratio (OR) 2.27 (95% confidence interval 1.40-3.69)], low income [OR 1.50 (1.02-2.21)] and renting tenure [OR 1.36 (1.01-1.84)]. Only tenure remained significant in fully adjusted models suggesting that co-variables were on the causal pathway. Albuminuria remained associated with several SES measures on full adjustment: low income [OR 1.55 (1.14-2.11)], no vehicle [OR 1.38 (1.05-1.81)], renting [OR 1.31 [1.03-1.67)] and most deprived area-level quintile [OR 1.55 (1.07-2.25)].

CONCLUSIONS

CKD 3-5 and albuminuria were associated with low SES using several measures. For albuminuria this was not explained by known measured causal factors.

Early life influences kidney function at age 63-64 years, but so does adult body size: results from the newcastle thousand families birth cohort

BACKGROUND

It is suggested that impaired fetal growth can affect kidney development, resulting in fewer glomeruli being formed and reduced kidney function later in life. The aim of this study was to investigate early life variables in relation to adult kidney function, and compare these to the influence of later life variables.

METHODS

Detailed information was collected prospectively regarding 1,142 babies, born in 1947 in Newcastle upon Tyne. At the age of 63-64 years, 335 participants had serum creatinine successfully measured and completed a lifestyle questionnaire. These measurements were used to calculate their estimated glomerular filtration rate (eGFR).

RESULTS

Body mass index (BMI) and being female were significantly negatively associated with eGFR. Birth weight was significantly positively associated with eGFR. In sex-specific analyses, BMI and cigarette smoking remained significant for males (n = 154), with a near significant association for birth weight, whereas none of the variables remained significant for females (n = 181).

CONCLUSIONS

The findings suggest that sex, size at birth and BMI may be important variables influencing adult kidney function. However, as only a small amount of variance in eGFR was explained by these variables, additional longitudinal studies would be beneficial for assessing lifecourse influences on kidney function.

The contextual influence of coal abandoned mine lands in communities and type 2 diabetes in Pennsylvania

Coal abandoned mine lands (AMLs), persistent and prevalent across Pennsylvania, offer an instructive evaluation of potential contextual influences of chronic environmental contamination (CEC) on individual health. We evaluated associations between the burden of AMLs, represented by 10 contextual metrics at the community level, and individual-level type 2 diabetes using hemoglobin A1c (HbA1c) as a biomarker. Cross-sectional and longitudinal multilevel analyses were conducted with over 28,000 diabetic primary care patients of the Geisinger Clinic. Adjusted models revealed five AML burden measures were associated (p<0.05), and three additional were borderline associated (0.05≤p≤0.10), with higher and/or change in HbA1c levels. This study provides key empirical evidence of adverse impacts of CEC in communities on an important chronic disease, illustrating the contextual effects of living in long-term degraded landscapes and communities.

Socio-economic impact in CKD

BACKGROUND

Socio-economic status (SES) may be conceptualized as an individual's position in society, as determined by their income, occupation, education, wealth, and housing situation. This review summarizes the current literature regarding associations of these markers of SES with both chronic kidney disease (CKD) and associated poor outcomes.

METHODS

Literature searches were conducted in the US National Library of Medicine, National Institutes of Health, PubMed database using the search terms "chronic kidney disease" and "chronic renal insufficiency," combined with "socio-economic status," "income," "occupation," "employment," "education," "social class," "wealth," and "housing." Articles not in the English language, using non-human subjects, or primarily concerning subjects with ESRD or acute kidney injury were excluded.

RESULTS

Income is the most-studied aspect of SES in relation to CKD, but there is increasing literature involving occupation and education as well. Additionally, the associations of CKD and its outcomes with area-level and life course SES are both burgeoning areas of research. There are several research areas that remain mostly unexplored, including the roles of wealth and housing in defining SES-related risk in CKD. Additionally, none have explored the relative utility of composite versus individual indicators of SES in predicting risk of CKD and outcomes.

CONCLUSION

Given the overwhelming evidence that SES plays an important role in the development and progression of disease, the development and testing of more targeted interventions should be a top priority in CKD research. Continuing examination of these factors, with increased rigor and focus on potentially modifiable intermediate pathways, is needed.

Prevalence and associations of limited health literacy in chronic kidney disease: a systematic review

BACKGROUND

Health literacy (HL) is important in chronic disease. This review aimed to evaluate the literature evidence on prevalence and associations of limited HL in chronic kidney disease (CKD).

METHODS

Seven databases were searched using terms for CKD and HL. Studies were included that ascertained the prevalence of limited HL using a validated tool in adults with CKD of any stage. The primary outcome was an objectively measured prevalence of limited HL in a population with CKD. The secondary outcome was associations of limited HL. Two reviewers assessed study inclusion and quality. Prevalence values were combined using a random-effect model to give overall prevalence.

RESULTS

Eighty-two studies were identified from searching, of which six met the inclusion criteria. The total number of people in all studies was 1405. Five studies were in dialysis or transplant populations, and all were from the USA. There was a significant heterogeneity in the prevalence of limited HL [9-32% (median 25%, inter-quartile range 16%)]. The pooled prevalence of limited HL in all studies was 22.7% (95% confidence interval 20.6-24.8%), but study heterogeneity limited the generalizability of this combined prevalence. The review identified associations between limited HL and socio-economic factors (lower education attainment, lower income), and certain process and outcome measures (lower likelihood of referral for transplant, higher mortality).

CONCLUSIONS

Limited HL is common among people with CKD and independently associated with socio-economic factors and health outcomes. It may represent an important determinant of inequality in CKD.

Determinants of incident chronic kidney disease and progression in a cohort of HIV-infected persons with unrestricted access to health care

OBJECTIVES

As socioeconomic factors may impact the risk of chronic kidney disease (CKD), we evaluated the incidence and risk factors of incident CKD among an HIV-infected cohort with universal access to health care and minimal injecting drug use (IDU).

METHODS

Incident CKD was defined as an estimated glomerular filteration rate (eGFR) <60 ml/min/1.73 m(2) for ≥ 90 days. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Rates were calculated per 1000 person-years (PY). Associations with outcomes were assessed using two separate Cox proportional hazard models, adjusting for baseline and time-updated covariates.

RESULTS

Among 3360 participants [median age 29 years; 92% male; 44% African American (AA)] contributing 23,091 PY of follow-up, 116 developed incident CKD [5.0/1000 PY; 95% confidence interval (CI) 4.2-6.0/1000 PY]. The median first eGFR value was 97.0 mL/min/1.73 m(2) [interquartile range (IQR) 85.3-110.1 mL/min/1.73 m(2)]. Baseline factors associated with CKD included older age, lower CD4 count at HIV diagnosis [compared with CD4 count ≥ 500 cells/μL, hazard ratio (HR) 2.1 (95% CI 1.2-3.8) for CD4 count 350-499 cells/μL; HR 3.6 (95% CI 2.0-6.3) for CD4 count 201-349 cells/μL; HR 4.3 (95% CI 2.0-9.4) for CD4 count ≤ 200 cells/μL], and HIV diagnosis in the pre-highly active antiretroviral therapy (HAART) era. In the time-updated model, low nadir CD4 counts, diabetes, hepatitis B, hypertension and less HAART use were also associated with CKD. AA ethnicity was not associated with incident CKD in either model.

CONCLUSIONS

The low incidence of CKD and the lack of association with ethnicity observed in this study may in part be attributable to unique features of our cohort such as younger age, early HIV diagnosis, minimal IDU, and unrestricted access to care. Lower baseline CD4 counts were significantly associated with incident CKD, suggesting early HIV diagnosis and timely introduction of HAART may reduce the burden of CKD.

Associations of the Burden of Coal Abandoned Mine Lands with Three Dimensions of Community Context in Pennsylvania

Background. Pennsylvania, with thousands of abandoned coal mines and miles of streams polluted with acid mine drainage, has the largest domestic coal mining burden contributing to deterioration of communities. Objectives. To evaluate contextual aspects by examining associations between coal abandoned mine lands (AML) and community measures of socioeconomic deprivation, social disorganization, and physical disorder. Methods. AML exposure data from the Reclaimed Abandoned Mine Land Inventory System were used to create density, diversity, accessibility, and clustering metrics. The three community context outcome measures were comprised of 14 census variables. In community-level analyses, 10 AML variables were evaluated separately with each dimension of community context, adjusting for covariates, in communities with and without abandoned mines. Results. We observed consistent associations between higher AML burden and worse socioeconomic deprivation, negative relations with social disorganization, but no statistically significant associations with physical disorder. Six of 10 AML variables were associated with socioeconomic deprivation, many consistently exhibiting exposure-effect patterns of worse deprivation with greater AML. Conclusions. Higher AML was associated with higher socioeconomic deprivation. These results can help prioritize the use of Surface Mining Control and Reclamation Act funds and inform decisions regarding Marcellus shale drilling to prevent analogous environmental degradation and public health impacts.

Association of deprivation with worse outcomes in chronic kidney disease: findings from a hospital-based cohort in the United Kingdom

BACKGROUND

Chronic kidney disease (CKD) prevalence and complications are known to be associated with deprivation, but there is limited understanding of the underlying reasons for inequalities.

AIMS

To evaluate the association of both individual and area level socioeconomic status (SES) with heavy proteinuria at presentation, progression of CKD, end-stage renal disease (ESRD) and death.

METHODS

A retrospective study of 918 CKD patients using integral multivariate logistic regression to adjust for known clinical and demographic explanatory variables.

RESULTS

During 3 years of median follow-up, 34% of the study population had progression of their CKD and of these, 32% experienced rapid progression. 23% presented with heavy proteinuria (urine protein:creatinine ratio ≥300 mg/mmol), 4% developed ESRD requiring renal replacement therapy and 10% died. Area level deprivation was independently associated with heavy proteinuria, progression and rapid progression of CKD. People living in the most deprived areas were more likely to develop ESRD. Unskilled professionals were more likely to experience a higher mortality rate.

CONCLUSION

Area level SES is inversely associated with both heavy proteinuria on presentation and progression as well as rapid progression of CKD. In contrast, individual level SES, unskilled professionals found to have a marginally significant association with increased risk of mortality. People living in more deprived areas presenting with CKD are likely to be at increased risk of poor outcomes and may need more active management and earlier referral.

Association between circulating specific leukocyte types and incident chronic kidney disease: the Atherosclerosis Risk in Communities (ARIC) study

Progressive renal fibrosis is a characteristic of all the diseases that cause renal failure and is invariably accompanied by a prominent leukocyte infiltration in the kidney. The goal of this study was to determine the association between the circulating specific leukocyte types and incident chronic kidney disease (CKD). In a cohort of 10,056 middle-aged white and African American adults, levels of circulating neutrophils, lymphocytes, and monocytes were measured at baseline; blood pressure (BP) and serum creatinine were measured and estimated glomerular filtration rate (eGFR) was calculated at baseline and 3 and 9 years later; and surveillance for first hospitalization or death with CKD was carried out over a mean follow-up of 7.4 years (maximum, 11.9 years). Increased neutrophil levels and decreased lymphocyte levels were significantly associated with greater CKD incidence after adjustment for covariates. African Americans tended to have similar but stronger patterns of association between circulating leukocytes and CKD incidence than whites, although the differences between race groups were not statistically significant. We also found that eGFR and BP were higher at each visit in African Americans than whites between ages 45 and 65. These findings support a potential role for circulating specific leukocytes in the pathogenesis of kidney dysfunction, especially in African Americans, indicating the leukocyte-related renal mechanism of essential hypertension (HT).