Excess risk of chronic kidney disease among African-American versus white subjects in the United States: a population-based study of potential explanatory factors

Ten years trajectories of estimated glomerular filtration rate (eGFR) in a multiethnic cohort of people with type 1 diabetes and preserved renal function

OBJECTIVES

We aim to evaluate estimated glomerular filtration rate (eGFR) patterns of progression in a multiethnic cohort of people with type I diabetes mellitus and with baseline eGFR ≥45 mL/min/1.73 m2.

DESIGN

Observational cohort.

SETTING

People with a clinical diagnosis of type 1 diabetes, attending two university hospital-based outpatient diabetes clinics, in South London between 2004 and 2018.

PARTICIPANTS

We studied 1495 participants (52% females, 81% white, 12% African-Caribbean and 7% others).

PRIMARY AND SECONDARY OUTCOME MEASURES

Clinical measures including weight and height, systolic blood pressure, diastolic blood pressure and laboratory results (such as serum creatinine, urine albumin to creatinine ratio (ACR), HbA1c were collected from electronic health records (EHRs) and eGFR was estimated by the Chronic Kidney Disease-Epidemiology Collaboration. Ethnicity was self-reported.

RESULTS

Five predominantly linear patterns/groups of eGFR trajectories were identified. Group I (8.5%) had a fast eGFR decline (>3 mL/min/1.73 m2 year). Group II (23%) stable eGFR, group III (29.8%), groups IV (26.3%) and V (12.4%) have preserved eGFR with no significant fall. Group I had the highest proportion (27.6%) of African-Caribbeans. Significant differences between group I and the other groups were observed in age, gender, HbA1C, systolic and diastolic blood pressure, body mass index, cholesterol and urine ACR, p<0.05 for all. At 10 years of follow-up, 33% of group I had eGFR <30 and 16.5%<15 (mL/min/1.73 m2).

CONCLUSIONS

Distinct trajectories of eGFR were observed in people with type 1 diabetes. The group with the highest risk of eGFR decline had a greater proportion of African-Caribbeans compared with others and has higher prevalence of traditional modifiable risk factors for kidney disease.

Racial Disparities in Endometrial Cancer Clinical Trial Representation: Exploring the Role of Eligibility Criteria

OBJECTIVE

This study aimed to determine whether Black patients with recurrent endometrial cancer were more likely than White patients to be ineligible for a recently published clinical trial due to specific eligibility criteria.

METHODS

Patients with recurrent or progressive endometrial cancer diagnosed from January 2010 to December 2021 who received care at a single institution were identified. Demographic and clinicopathologic information was abstracted and determination of clinical trial eligibility was made based on 14 criteria from the KEYNOTE-775 trial. Characteristics of the eligible and ineligible cohorts were compared, and each ineligibility criterion was evaluated by race.

RESULTS

One hundred seventy-five patients were identified, 89 who would have met all inclusion and no exclusion criteria for KEYNOTE-775, and 86 who would have been ineligible by one or more exclusion criteria. Patients in the ineligible cohort were more likely to have lower BMI (median 26.5 vs. 29.2, P <0.001), but were otherwise similar with regard to insurance status, histology, and stage at diagnosis. Black patients had 33% lower odds of being eligible (95% CI: 0.33-1.34) and were more likely to meet the exclusion criterion of having a previous intestinal anastomosis, but the result was not statistically significant. If this criterion were removed, the racial distribution of those ineligible for the trial would be more similar (46.4% Black vs. 42.2% White).

CONCLUSIONS

Clinical trial eligibility criteria may contribute to the underrepresentation of racial groups in clinical trials, but other factors should be explored. Studies to quantify and lessen the impact of implicit bias are also needed.

Proneurotensin/Neuromedin N and Risk of Incident CKD and Other Kidney Outcomes in Community-Living Individuals: The REGARDS Study

Rationale & Objective

Plasma proneurotensin/neuromedin N (pro-NT/NMN) is a precursor of neurotensin, a tridecapeptide linked with type 2 diabetes mellitus and other comorbid conditions associated with kidney disease. Whether pro-NT/NMN is directly associated with incident chronic kidney disease (CKD), and whether that association differs by race, is uncertain. We evaluated whether pro-NT/NMN levels were associated with increased risk of kidney outcomes.

Study Design

Prospective cohort.

Setting & Participants

Participants in Biomarker Mediators of Racial Disparities in Risk Factors, a nested cohort from the REasons for Geographic And Racial Differences in Stroke study, with available stored serum and urine samples from baseline and second visits for biomarker measurement.

Exposure

Baseline log-transformed pro-NT/NMN.

Outcomes

Incident CKD, progressive estimated glomerular filtration rate (eGFR) decline, incident albuminuria, and incident kidney failure within median follow-up time of 9.4 years.

Analytical Approach

Logistic regression.

Results

Among 3,914 participants, the mean ± SD age was 64 ± 8 (SD) years, 48% were women, and 51% were Black. Median baseline eGFR was 90 (IQR, 77-102) mL/min/1.73 m2. Each SD higher of pro-NT/NMN was associated with 9% higher odds of progressive eGFR decline (OR, 1.09; 95% CI, 1.00-1.20). There was no association observed with incident CKD (OR, 1.10; 95% CI, 0.96-1.27), incident albuminuria (OR, 1.08; 95% CI, 0.96-1.22), or incident kidney failure (OR, 1.10; 95% CI, 0.83-1.46). There were no differences in results by race or sex.

Limitations

Single measurement of pro-NT/NMN and limited generalizability.

Conclusions

Higher pro-NT/NMN was associated with progressive eGFR decline but no other manifestations of kidney disease incidence.

APOL1 Kidney Risk Variants and Long-Term Kidney Function in Healthy Middle-Aged Black Individuals: The Atherosclerosis Risk in Communities (ARIC) Study

Rationale & Objective

The effect of apolipoprotein L1(APOL1) genotype on future risk of kidney disease among middle-aged individuals with good kidney function is not well established.

Study Design

Longitudinal cohort study.

Setting & Participants

In total, 5,886 healthy individuals (45-64 years old) enrolled in the Atherosclerosis Risk in Communities study with creatinine-based estimated glomerular filtration rate ≥ 80 mL/min who would be suitable kidney donors.

Exposures

Race and APOL1 genotype.

Outcomes

Creatinine- and cystatin C-based estimated glomerular filtration rate (eGFRcr-cys) using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation, urinary albumin-creatinine ratio (UACR), proportion with chronic kidney disease (CKD) 3a or worse, end-stage kidney disease (ESKD), and death.

Analytical Approach

Participants grouped based on race and APOL1 genotype. Compared eGFRcr-cys and UACR across groups. Multinomial logistic regression models were used compare odds of CKD. Kaplan-Meier survival curves were created to compare rates of ESKD and death at last follow-up.

Results

There were 5,075 Whites (86%), 701 Blacks carrying the low-risk APOL1 genotype (12%), and 110 Blacks carrying the high-risk APOL1 genotype (2%). The mean age at baseline was 53 ± 6 years. At 10 years, White participants had lower eGFRcr-cys than low-risk and high-risk groups (89 ± 16 vs 91 ± 16 and 92 ± 15 mL/min/1.73 m2, respectively; P < 0.001). At 25 years, White participants continued to have lower eGFRcr-cys than the low-risk group (70 ± 18 vs 72 ± 19 mL/min/1.73 m2; P < 0.001) but not compared with the high-risk APOL1 genotype (67±23 mL/min/1.73 m2). There was no difference in UACR among groups at 10 and 25 years (P = 0.87 and 0.91, respectively). The odds of developing CKD stage 3a or worse were not different between low-risk and high-risk APOL1 group in both unadjusted and adjusted models (P = 0.26 and P = 0.39, respectively). At last follow-up, <5% developed ESKD, and 45% of individuals either died or reached ESKD with no difference in outcomes between the groups.

Limitations

Low ascertainment because of death and long follow-up.

Conclusions

Among middle-aged individuals, APOL1 genotype does not appear to be a major driver of future risk of kidney disease.

Smoking Increases Mortality Risk Among African Americans With Chronic Kidney Disease

Background

Smoking and chronic kidney disease (CKD) have a disproportionately high prevalence among African American (AA) adults, but their impact on mortality among AA adults is not well known.

Methods

Given the lack of evidence in published literature on specific factors affecting the relationship between CKD and mortality among AA adults, we examined the influence of smoking on mortality among AA adults with CKD. National Health and Nutrition Examination Survey (NHANES, 1999-2010) data were analyzed with study participants prospectively followed up for mortality analysis through December 31, 2019, using National Death Index (NDI) death certificate records.

Results

A total of 6,108 AA adults were included in the study sample, with more than two-fifths (44.9%) being smokers and 6.3% having CKD. AA individuals with CKD had 2.22 (95% CI = 1.38-3.57) times the risk of cardiovascular mortality, but when stratified by smoking, AA individuals with CKD who were current smokers had 3.21 times the risk of cardiovascular mortality. Similarly, in AA with CKD, the risk of all-cause mortality was 3.53 (95% CI = 1.31-9.47), but when stratified by smoking status, AA individuals with CKD who were current smokers had 5.54 times the risk of all-cause mortality.

Conclusions

Smoking and CKD are highly prevalent in AA individuals and frequently cooccur, leading to higher rates of mortality. Smoking cessation interventions should be a priority in collaborative care models and interdisciplinary care teams for AA with CKD and current smoker status.

Role of Age and Competing Risk of Death in the Racial Disparity of Kidney Failure Incidence after Onset of CKD

SIGNIFICANCE STATEMENT

Black adults in the United States have 2-4 times higher incidence of kidney failure than White adults. Yet, the reasons underlying this disparity remain poorly understood. Among 547,188 US veterans with new-onset CKD, according to a new race-free GFR equation, Black veterans had a 2.5-fold higher cumulative incidence of kidney failure, compared with White veterans, in any follow-up period from CKD onset. This disparity resulted from a combination of higher hazards of progression to kidney failure and lower hazards of competing-risk death in Black veterans. Both, in turn, were largely explained by the younger age at CKD onset in Black veterans, underscoring an urgent need to prevent early onset and slow progression of CKD in younger Black adults.

BACKGROUND

The Black adult population is well known to have higher incidence of kidney failure than their White counterpart in the United States, but the reasons underlying this disparity are unclear. We assessed the racial differences in kidney failure and death from onset of CKD on the basis of the race-free 2021 CKD Epidemiology Collaboration equation and examined the extent to which these differences could be explained by factors at the time of CKD onset.

METHODS

We analyzed a national cohort consisting of 547,188 US veterans (103,821 non-Hispanic Black and 443,367 non-Hispanic White), aged 18-85 years, with new-onset CKD between 2005 and 2016 who were followed through 10 years or May 2018 for incident kidney failure with replacement therapy (KFRT) and pre-KFRT death.

RESULTS

At CKD onset, Black veterans were, on average, 7.8 years younger than White veterans. In any time period from CKD onset, the cumulative incidence of KFRT was 2.5-fold higher for Black versus White veterans. Meanwhile, Black veterans had persistently >2-fold higher hazards of KFRT throughout follow-up (overall hazard ratio [95% confidence interval], 2.38 [2.31 to 2.45]) and conversely had 17%-48% decreased hazards of pre-KFRT death. These differences were reduced after accounting for the racial difference in age at CKD onset.

CONCLUSIONS

The 2.5-fold higher cumulative incidence of kidney failure in Black adults resulted from a combination of higher hazards of progression to kidney failure and lower hazards of the competing risk of death, both of which can be largely explained by the younger age at CKD onset in Black compared with White adults.

The Fruit and Veggies for Kidney Health Study: A Prospective Randomized Trial

Rationale & Objective

Providing fruits and vegetables (F&Vs) to health care system patients with elevated urine albumin-creatinine ratio (ACR) reduced ACR, slowed chronic kidney disease (CKD) progression and reduced cardiovascular disease (CVD) risk factors in previous studies. This study evaluated a community-based strategy in lower-income populations to identify African Americans with elevated ACR before health care system involvement and sustain them in a 6-month F&V protocol with (F&V + Cook) and without (F&V Only) cooking instructions, with the hypothesis that adjuvant cooking instructions with F&Vs would further reduce ACR.

Study Design

Prospective, randomized, parallel 2-arm design.

Setting & Participants

African American adults with ACR >10 mg/g creatinine randomized to 1 of 2 study arms.

Interventions

Two cups/day of F&Vs with or without cooking instructions in participants followed 6 months.

Outcomes

Participants sustaining the F&V protocol and between-group indicators of CVD risk, kidney injury, and dietary intake at 6 weeks and 6 months.

Results

A total of 142 African American adults (mean age, 57.0 years; ACR, 27.4 mg/g; body mass index, 34.4; 24.9% CKD 1; 24.8% CKD 2; 50.4% CKD 3; 55% female) randomized to F&V Only (n=72) or F&V + Cook (n=70), and 71% were retained at 6 months. Participants received 90% of available F&V pick-ups over 6 weeks and 69% over 6 months. In the adjusted model, 6-month ACR was 31% lower for F&V + Cook than F&V Only (P = 0.02). Net 6-week F&V intake significantly increased and biometric variables improved for participants combined into a single group.

Limitations

Small sample size, low-baseline ACR, and potential nonresponse bias for 24-hour dietary recall measure.

Conclusions

These data support the feasibility of identifying community-dwelling African Americans with ACR indicating elevated CVD and CKD risk and sustaining a F&V protocol shown to improve kidney outcomes and CVD risk factors and provides preliminary evidence that cooking instructions adjuvant to F&Vs are needed to lower ACR.

Funding

National Institute on Diabetes, Digestive, and Kidney Diseases grant "Reducing chronic kidney disease burden in an underserved population" (R21DK113440).

Trial Registration

NCT03832166.

Plain-Language Summary

African Americans, particularly those in low-income communities, have increased rates of chronic kidney disease (CKD) with worsening outcomes over time. Giving fruits and vegetables to individuals with CKD identified in health care systems was previously shown to reduce kidney damage, measured by urine protein albumin, and slow kidney function decline. We recruited African Americans in low-income communities with increased urine albumin levels. They received fruits and vegetables for 6 months, and we tested whether added cooking instructions further reduced urine albumin levels. Most participants continued to receive fruits and vegetables throughout the 6 months. Those given cooking instructions had lower urine albumin levels after 6 months, indicating decreased kidney damage. Providing cooking instructions with fruits and vegetables appears to lessen kidney damage more than just fruits and vegetables alone.

Structural and Psychosocial Challenges Among Underserved Patients Receiving Hemodialysis During and Beyond the COVID-19 Pandemic: A Qualitative Study

Rationale & Objective

Racial and ethnic minority groups in the United States are disproportionately affected by chronic kidney disease and progressive kidney failure and face significantly more socioeconomic and psychosocial challenges. However, how such patients' social environment and stigmatization shape their illness experiences and abilities to cope before and during the coronavirus disease 2019 (COVID-19) pandemic has not been well documented, even as social scientific research predicts these groups' exponential vulnerability.

Study Design

Qualitative study using semistructured interviews to elicit individual patient narratives about their personal illness experiences before and during the COVID-19 pandemic, any challenges they faced, and their sources of support.

Setting & Participants

Using purposive sampling, we recruited 20 adult patients receiving maintenance hemodialysis from centers affiliated with a safety-net hospital in Boston, Massachusetts.

Analytical Approach

Interviews were audiotaped, transcribed, and analyzed using thematic content analysis to identify patients' challenges and supports before and during the pandemic.

Results

Of the 20 patients in the study, 9 were women, and 18 self-identified as Black or African American. Three main themes emerged, whereby most patients described: (1) stigma and stigmatization as a central element of their life experience; (2) the pandemic as a difficult experience but not a complete rupture from their prepandemic life; and (3) social networks, particularly family, friends, and religious communities, as sources of support crucial to coping with their debilitating illness.

Limitations

Whether the findings apply to other settings is unknown, as participants were recruited from centers in a single safety-net urban hospital setting.

Conclusions

Psychosocial and environmental factors, including institutional racism and stigmatization, play significant roles in amplifying the burdens shouldered by racial and ethnic minority individuals with kidney disease who now also face the COVID-19 pandemic that has since turned endemic. The results of this study can inform the development of policy interventions aimed at alleviating tensions and structural conditions that impinge on kidney disease patients' wellbeing and health outcomes.

Plain-Language Summary

Members of racial and ethnic minority groups in the United States experience the highest rates of progressive kidney failure and face significantly more socioeconomic and psychosocial challenges. We interviewed 20 patients who receive maintenance hemodialysis treatment from centers affiliated with a safety-net hospital. Patients described stigmatization as a central element of their life experience and the pandemic as a difficult challenge (but not a complete rupture) that added to their struggles with illness-related, race-related, and class-related stigmas. Social networks, particularly family, friends, and religious communities, are key sources of support crucial to coping with illness. Findings from this study can inform health care providers and community workers and guide the development of policy interventions to provide better support for these patients.

Trends and Race/Ethnic Disparities in Diabetes-Related Hospital Use in Medicaid Enrollees: Analyses of Serial Cross-sectional State Data, 2008-2017

BACKGROUND

Race/ethnic disparities in preventable diabetes-specific hospital care may exist among adults with diabetes who have Medicaid coverage.

OBJECTIVE

To examine race/ethnic disparities in utilization of preventable hospital care by adult Medicaid enrollees with diabetes across nine states over time.

DESIGN

Using serial cross-sectional state discharge records for emergency department (ED) visits and inpatient (IP) hospitalizations from the Healthcare Cost and Utilization Project, we quantified race/ethnicity-specific, state-year preventable diabetes-specific hospital utilization.

PARTICIPANTS

Non-Hispanic Black, non-Hispanic White, and Hispanic adult Medicaid enrollees aged 18-64 with a diabetes diagnosis (excluding gestational or secondary diabetes) who were discharged from hospital care in Arizona, Iowa, Kentucky, Florida, Maryland, New Jersey, New York, North Carolina, and Utah for the years 2008, 2011, 2014, and 2017.

MAIN MEASURES

Non-Hispanic Black-over-White and Hispanic-over-White rate ratios constructed using age- standardized state-year, race/ethnicity-specific ED, and IP diabetes-specific utilization rates.

KEY RESULTS

The ratio of Black-over-White ED utilization rates for preventable diabetes-specific hospital care increased across the 9 states in our sample from 1.4 (CI 95, 1.31-1.50) in 2008 to 1.73 (CI 95, 1.68-1.78) in 2017. The cross-year-state average non-Hispanic Black-over-White IP rate ratio was 1.46 (CI 95, 1.42-1.50), reflecting increases in some states and decreases in others. The across-state-year average Hispanic-over-White rate ratio for ED utilization was 0.67 (CI 95, 0.63-0.71). The across-state-year average Hispanic-over-White IP hospitalization rate ratio was 0.72 (CI 95, 0.69-0.75).

CONCLUSIONS

Hospital utilization by non-Hispanic Black Medicaid enrollees with diabetes was consistently greater and often increased relative to utilization by White enrollees within state programs between 2008 and 2017. Hispanic enrollee hospital utilization was either lower or indistinguishable relative to White enrollee hospital utilization in most states, but Hispanic utilization increased faster than White utilization in some states. Among broader patterns, there is heterogeneity in the magnitude of race/ethnic disparities in hospital utilization trends across states.

Implementation of a culturally competent APOL1 genetic testing programme into living donor evaluation: A two-site, non-randomised, pre-post trial design

INTRODUCTION

While living donor (LD) kidney transplantation is the optimal treatment for patients with kidney failure, LDs assume a higher risk of future kidney failure themselves. LDs of African ancestry have an even greater risk of kidney failure post-donation than White LDs. Because evidence suggests that Apolipoprotein L1 (APOL1) risk variants contribute to this greater risk, transplant nephrologists are increasingly using APOL1 genetic testing to evaluate LD candidates of African ancestry. However, nephrologists do not consistently perform genetic counselling with LD candidates about APOL1 due to a lack of knowledge and skill in counselling. Without proper counselling, APOL1 testing will magnify LD candidates' decisional conflict about donating, jeopardising their informed consent. Given cultural concerns about genetic testing among people of African ancestry, protecting LD candidates' safety is essential to improve informed decisions about donating. Clinical 'chatbots', mobile apps that provide genetic information to patients, can improve informed treatment decisions. No chatbot on APOL1 is available and no nephrologist training programmes are available to provide culturally competent counselling to LDs about APOL1. Given the shortage of genetic counsellors, increasing nephrologists' genetic literacy is critical to integrating genetic testing into practice.

METHODS AND ANALYSIS

Using a non-randomised, pre-post trial design in two transplant centres (Chicago, IL, and Washington, DC), we will evaluate the effectiveness of culturally competent APOL1 testing, chatbot and counselling on LD candidates' decisional conflict about donating, preparedness for decision-making, willingness to donate and satisfaction with informed consent and longitudinally evaluate the implementation of this intervention into clinical practice using the Reach, Effectiveness, Adoption, Implementation and Maintenance framework.

ETHICS AND DISSEMINATION

This study will create a model for APOL1 testing of LDs of African ancestry, which can be implemented nationally via implementation science approaches. APOL1 will serve as a model for integrating culturally competent genetic testing into transplant and other practices to improve informed consent. This study involves human participants and was approved by Northwestern University IRB (STU00214038). Participants gave informed consent to participate in the study before taking part.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04910867. Registered 8 May 2021, https://register.

CLINICALTRIALS

gov/prs/app/action/SelectProtocol?sid=S000AWZ6&selectaction=Edit&uid=U0001PPF&ts=7&cx=-8jv7m2 ClinicalTrials.gov Identifier: NCT04999436. Registered 5 November 2021, https://register.

CLINICALTRIALS

gov/prs/app/action/SelectProtocol?sid=S000AYWW&selectaction=Edit&uid=U0001PPF&ts=11&cx=9tny7v.

The Morality of Kidney Sales: When Caring for the Seller's Dignity Has Moral Costs

Kidney markets are prohibited in principle because they are assumed to undermine the seller's dignity. Considering the trade-off between saving more lives by introducing regulated kidney markets and preserving the seller's dignity, we argue that it is advisable to demand that citizens restrain their own moral judgements and not interfere with the judgements of those who are willing to sell a kidney. We also argue that it is advisable not only to limit the political implications of the moral argument of dignity concerns toward a market-based solution but also to re-evaluate the dignity argument itself. First, if the dignity argument is to be given normative force, it must also consider the dignity violation of the potential transplant recipient. Second, there seems to be no compelling notion of dignity that demonstrates why it is morally permissible to donate but not to sell a kidney.

Psychosocial Distress in Patients With Advanced CKD by Racial Group and Immigrant Status: A Canadian Cross-sectional Study

RATIONALE & OBJECTIVE

Patients with advanced chronic kidney disease (CKD) have been reported to experience profound psychosocial distress. Other work has established that patients with CKD from marginalized populations (including individuals who on the basis of race often face racism and related discrimination, termed "racialization") experience health care inequities. Given limited information on the intersection of these 2 phenomena, we assessed the association of psychosocial distress with racialized status and immigrant status in Canadians with advanced CKD.

STUDY DESIGN

Secondary analysis of cross-sectional data.

SETTING & PARTICIPANTS

536 patients with advanced CKD (estimated glomerular filtration rate<30mL/min/1.73m², with or without kidney replacement therapy) from multiple clinical centers in Toronto.

EXPOSURE

Racialized status (individuals who identify as Asian or as African, Caribbean, or Black Canadian), immigrant status, and combined immigrant-racialized status.

OUTCOME

Psychosocial distress, defined as the presence of depression, anxiety, or social difficulties (ie, a score of≥10 points on the Patient Health Questionnaire 9, Generalized Anxiety Disorder 7, or Social Distress 16 scales, respectively).

ANALYTICAL APPROACH

The independent associations of racialized status and immigrant status with psychosocial distress, depression, anxiety, and social difficulties were examined using univariable- and multivariable-adjusted logistic regression.

RESULTS

Mean age of the 536 participants was 57±16 (SD) years, 62% were male, and 45% were immigrants. Of the sample, 58% were White, 22% were African, Caribbean, or Black Canadian, and 20% were Asian. Psychosocial distress was present in 36% of participants (depression in 19%, anxiety in 12%, and social difficulties in 31%). To assess the combined impact of racialized and immigrant status, we created a variable with mutually exclusive categories: White nonimmigrant, racialized nonimmigrant, White immigrant, and racialized immigrant participants. In our final multivariable-adjusted model, compared with White nonimmigrant participants, racialized immigrant participants were more likely to have psychosocial distress (OR, 2.96 [95% CI, 1.81-4.81]), depression (OR, 1.87 [95% CI, 1.05-3.34]), and social difficulties (OR, 3.36 [95% CI, 2.03-5.57]). Overall similar associations were seen for racialized nonimmigrants and for White immigrants.

LIMITATIONS

Convenience sample; small subgroups; combined exposure variable grouping Asian and African, Caribbean, and Black participants together; lack of data about mechanisms.

CONCLUSIONS

Both racialized and immigrant status based on self-report of demographic characteristics were associated with psychosocial distress among patients with advanced CKD. These patients may benefit from culturally competent psychosocial support.

PLAIN-LANGUAGE SUMMARY

Psychosocial distress is frequent in patients with advanced chronic kidney disease and impacts quality of life and clinical outcomes. Psychosocial distress may be especially scarring in people who are racialized (marginalized on account of their membership in a particular racial group) and/or who are immigrants. We assessed the association of psychosocial distress with racialized and immigrant status in Canadians with advanced chronic kidney disease. Among 536 participants from multiple medical centers in Toronto, we found that racialized and immigrant participants were more likely to have psychosocial distress, depression, and social difficulties compared with White nonimmigrant participants. This is likely related to the multiple intersectional challenges, including experience with racism and discrimination that racialized immigrant patients may face. Further studies are needed to elucidate the specific factors that contribute to more distress. The potential impact of culturally competent and safe support for these patients will also need to be studied.

Clinical Risk Factors For Kidney Tubule Biomarker Abnormalities Among Hypertensive Adults With Reduced eGFR in the SPRINT Trial

BACKGROUND

Urine biomarkers of kidney tubule health may distinguish aspects of kidney damage that cannot be captured by current glomerular measures. Associations of clinical risk factors with specific kidney tubule biomarkers have not been evaluated in detail.

METHODS

We performed a cross-sectional study in the Systolic Blood Pressure Intervention Trial among 2,436 participants with a baseline estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2. Associations between demographic and clinical characteristics with urine biomarkers of kidney tubule health were evaluated using simultaneous multivariable linear regression of selected variables.

RESULTS

Each standard deviation higher age (9 years) was associated with 13% higher levels of chitinase-3-like protein-1 (YKL-40), indicating higher levels of tubulointerstitial inflammation and repair. Men had 31% higher levels of alpha-1 microglobulin and 16% higher levels of beta-2 microglobulin, reflecting worse tubule resorptive function. Black race was associated with significantly higher levels of neutrophil gelatinase-associated lipocalin (12%) and lower kidney injury molecule-1 (26%) and uromodulin (22%). Each standard deviation (SD) higher systolic blood pressure (SBP) (16 mmHg) was associated with 10% higher beta-2 microglobulin and 10% higher alpha-1 microglobulin, reflecting lower tubule resorptive function.

CONCLUSIONS

Clinical and demographic characteristics, such as race, sex, and elevated SBP, are associated with unique profiles of tubular damage, which could reflect under-recognized patterns of kidney tubule disease among persons with decreased eGFR.

Clinical outcomes and echocardiographic characteristics between African American and Caucasian patients with acute pulmonary embolism

Background

Despite socioeconomic disparities, no association between clinical presentation and poor outcomes explains a higher mortality in African Americans with pulmonary embolism (PE). The objective is to identify the co-morbidities and echocardiographic characteristics associated with increased mortality in African American patients.

Methods

This is a cross-sectional study of Caucasian or African American patients with PE diagnosed between October 2015 and December 2017 at University of Maryland Medical Center. The outcomes were in-hospital death, length of stay, and bleeding.

Results

There were 303 African Americans and 343 Caucasians. Caucasians were older ( p = 0.007), males ( p = 0.01) with history of coronary artery revascularization (CABG ( p = 0.001), coronary stents ( p = 0.001)), trauma ( p = 0.007), and/or recent surgeries ( p = 0.0001). African Americans exhibited higher rates of diabetes ( p = 0.01), chronic kidney disease ( p = 0.0005), and smoking ( p = 0.04). Severity of PE was similar between groups and there was no difference in clot burden size. African Americans had more right ventricular strain on Computer Tomography ( p = 0.001) and echocardiogram ( p = 0.004); also, underfilled left ventricles ( p = 0.02) and higher right ventricular systolic pressures ( p = 0.001). There was no difference in hospital mortality (7.1% vs. 7.9%, p = 0.71), length of stay (13.1 ± 16.7 vs 12.8 ± 14.9, p = 0.80) and bleeding (9.0% vs.8.3%. p = 0.72). Mortality was higher in African Americans who received advanced therapies (3.8% vs. 18.8%, p = 0.02). The risk of death increased with age (OR 1.04; 95%CI 1.020–1.073) and with advanced therapies (OR 2.43; 95%CI 1.029–5.769).

Conclusions

Differences in co-morbidities, radiologic findings, and echocardiographic characteristics that may contribute to higher mortality in African American patients, specifically those receiving advanced therapies.

Oncosurgery-Related Acute Kidney Injury

Oncosurgery is a surgical specialty that focuses on the diagnosis, staging, and management of cancer and cancer-related complications. Acute kidney injury is a common and important complication related to oncologic surgery, associated with longer hospital length of stay, greater costs, increased risk of incident or progressive chronic kidney disease (CKD), and higher mortality. The pathogenesis of oncosurgery-related acute kidney injury is multifactorial and determined by different variables, including patient characteristics (comorbidities, volume status, age, pre-existing CKD), specific cancer type or location, surgical procedure involved, as well as intrinsic neuroendocrine and hemodynamic responses to anesthesia and/or surgery. Early nephrology evaluation may be helpful to assist with preservation of kidney function and prevention of further kidney injury.

Alpha Globin Gene Copy Number Is Associated with Prevalent Chronic Kidney Disease and Incident End-Stage Kidney Disease among Black Americans

BACKGROUND

α-Globin is expressed in endothelial cells of resistance arteries, where it limits endothelial nitric oxide signaling and enhances α-adrenergic-mediated vasoconstriction. α-Globin gene (HBA) copy number is variable in people of African descent and other populations worldwide. Given the protective effect of nitric oxide in the kidney, we hypothesized that HBA copy number would be associated with kidney disease risk.

METHODS

Community-dwelling Black Americans aged ≥45 years old were enrolled in a national longitudinal cohort from 2003 through 2007. HBA copy number was measured using droplet digital PCR. The prevalence ratio (PR) of CKD and the relative risk (RR) of incident reduced eGFR were calculated using modified Poisson multivariable regression. The hazard ratio (HR) of incident ESKD was calculated using Cox proportional hazards multivariable regression.

RESULTS

Among 9908 participants, HBA copy number varied from 2 to 6. In analyses adjusted for demographic, clinical, and genetic risk factors, a one-copy increase in HBA was associated with 14% greater prevalence of CKD (PR, 1.14; 95% CI, 1.07 to 1.21; P<0.0001). While HBA copy number was not associated with incident reduced eGFR (RR, 1.06; 95% CI, 0.94 to 1.19; P=0.38), the hazard of incident ESKD was 32% higher for each additional copy of HBA (HR, 1.32; 95% CI, 1.09 to 1.61; P=0.005).

CONCLUSIONS

Increasing HBA copy number was associated with a greater prevalence of CKD and incidence of ESKD in a national longitudinal cohort of Black Americans.

Etiology of Kidney Diseases With Proteinuria in the Gambia/West Africa

In West Africa, kidney diseases are frequently seen, but diagnostic and therapeutic options are poor due to limited access to specialized facilities. To unravel the etiology and develop clinical guidelines, we collected clinical data and results of kidney biopsies in 121 pediatric and mostly young adult patients with edema and proteinuria in The Gambia. Workup included clinical examination, urine and serum analysis, and kidney biopsy findings. Selected cases were treated with steroids.

RESULTS

The median age was 14.9 years (range 1.8-52.0) at presentation. The most frequent underlying histologies were post-infectious glomerulonephritis (PIGN) in 38%, focal-segmental glomerulosclerosis (FSGS) in 30%, minimal change nephrotic syndrome (MCNS) in 15%, and membranous glomerulonephritis (MGN) in 10% of cases. Patients with PIGN were significantly younger and had less proteinuria and higher serum albumin levels than the other three. Infected scabies was seen more often in cases with PIGN. Clinical parameters could not distinguish patients with FSGS, MCNS, and MGN. Steroid response was prompt in patients with MCNS (remission in 10/10 cases) compared to FSGS (4/19) and MGN (0/4). In summary, the clinical histopathological correlation allows a better approach to therapy and can be the basis for urgently needed interventional studies in steroid-resistant cases.

Replication of European hypertension associations in a case-control study of 9,534 African Americans

Objective

Hypertension is more prevalent in African Americans (AA) than other ethnic groups. Genome-wide association studies (GWAS) have identified loci associated with hypertension and other cardio-metabolic traits like type 2 diabetes, coronary artery disease, and body mass index (BMI), however the AA population is underrepresented in these studies. In this study, we examined a large AA cohort for the generalizability of 14 Metabochip array SNPs with previously reported European hypertension associations.

Methods

To evaluate associations, we analyzed genotype data of 14 SNPs for their associations with a diagnosis of hypertension, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in a case-control study of an AA population (N = 9,534). We also performed an age-stratified analysis (>30, 30≥59 and ≥60 years) following the hypertension definition described by the 8th Joint National Committee (JNC). Associations were adjusted for BMI, age, age², sex, clinical confounders, and genetic ancestry using multivariable regression models to estimate odds ratios (ORs) and beta-coefficients. Analyses stratified by sex were also conducted. Meta-analyses (including both BioVU and COGENT-BP cohorts) were performed using a random-effects model.

Results

We found rs880315 to be associated with systolic hypertension (SBP≥140 mmHg) in the entire cohort (OR = 1.14, p = 0.003) and within women only (OR = 1.16, p = 0.012). Variant rs17080093 associated with lower SBP and DBP (β = -2.99, p = 0.0352 and - β = 1.69, p = 0.0184) among younger individuals, particularly in younger women (β = -3.92, p = 0.0025 and β = -1.87, p = 0.0241 for SBP and DBP respectively). SNP rs1530440 associated with higher SBP and DBP measurements (younger individuals β = 4.1, p = 0.039 and β = 2.5, p = 0.043 for SBP and DBP; (younger women β = 4.5, p = 0.025 and β = 2.9, p = 0.028 for SBP and DBP), and hypertension risk in older women (OR = 1.4, p = 0.050). rs16948048 increases hypertension risk in younger individuals (OR = 1.31, p = 0.011). Among mid-age women rs880315 associated with higher risk of hypertension (OR = 1.20, p = 0.027). rs1361831 associated with DBP (β = -1.96, p = 0.02) among individuals older than 60 years. rs3096277 increases hypertension risk among older individuals (OR = 1.26 p = 0.0015), however, this variant also reduces SBP among younger women (β = -2.63, p = 0.0102).

Conclusion

These findings suggest that European-descent and AA populations share genetic loci that contribute to blood pressure traits and hypertension. However, the OR and beta-coefficient estimates differ, and some are age-dependent. Additional genetic studies of hypertension in AA are warranted to identify new loci associated with hypertension and blood pressure traits in this population.

The Use of 'Omics for Diagnosing and Predicting Progression of Chronic Kidney Disease: A Scoping Review

Globally, chronic kidney disease (CKD) contributes substantial morbidity and mortality. Recently, various 'omics platforms have provided insight into the molecular basis of kidney dysfunction. This scoping review is a synthesis of the current literature on the use of different 'omics platforms to identify biomarkers that could be used to detect early-stage CKD, predict disease progression, and identify pathways leading to CKD. This review includes 123 articles published from January 2007 to May 2021, following a structured selection process. The most common type of 'omic platform was proteomics, appearing in 55 of the studies and two of these included a metabolomics component. Most studies (n = 91) reported on CKD associated with diabetes mellitus. Thirteen studies that provided information on the biomarkers associated with CKD and explored potential pathways involved in CKD are discussed. The biomarkers that are associated with risk or early detection of CKD are SNPs in the MYH9/APOL1 and UMOD genes, the proteomic CKD273 biomarker panel and metabolite pantothenic acid. Pantothenic acid and the CKD273 biomarker panel were also involved in predicting CKD progression. Retinoic acid pathway genes, UMOD, and pantothenic acid provided insight into potential pathways leading to CKD. The biomarkers were mainly used to detect CKD and predict progression in high-income, European ancestry populations, highlighting the need for representative 'omics research in other populations with disparate socio-economic strata, including Africans, since disease etiologies may differ across ethnic groups. To assess the transferability of findings, it is essential to do research in diverse populations.

Delay Early CKD with Lifestyle Intervention in African Americans with Diabetic Kidney Disease (DELAY DKD): A Pre-Post Pilot Study (Preprint)

Background

Behavioral factors, such as lifestyle, have been shown to explain approximately 24% of the excess risk of chronic kidney disease (CKD) among African Americans. However, there are limited intervention studies culturally tailored to African Americans with type 2 diabetes mellitus and CKD.

Objective

The main objective of this study was to examine the feasibility and preliminary efficacy of a culturally tailored lifestyle intervention among African Americans with type 2 diabetes mellitus and CKD.

Methods

A pre-post design was used to test the feasibility of a lifestyle intervention in 30 African American adults recruited from the Medical University of South Carolina between January 2017 and February 2017. A research nurse delivered the manualized study intervention weekly for 6 weeks. Clinical outcomes (hemoglobin A_1c, blood pressure, and estimated glomerular filtration rate [eGFR]) were measured at baseline and postintervention. Disease knowledge, self-care, and behavior outcomes were also measured using validated structured questionnaires at baseline and postintervention. Descriptive statistics and effect sizes were calculated to determine clinically important changes from baseline.

Results

Significant pre-post mean differences and decreases were observed for hemoglobin A_1c (mean 0.75%, 95% CI 0.16-1.34; P=.01), total cholesterol (mean 16.38 mg/dL, 95% CI 5.82-26.94; P=.004), low-density lipoprotein (mean 13.73 mg/dL, 95% CI 3.91-23.54; P=.008), and eGFR (mean 6.73 mL/min/1.73m², 95% CI 0.97-12.48; P=.02). Significant pre-post mean differences and increases were observed for CKD self-efficacy (mean −11.15, 95% CI −21.55 to −0.75; P=.03), CKD knowledge (mean −2.62, 95% CI −3.98 to −1.25; P<.001), exercise behavior (mean −1.21, 95% CI −1.96 to −0.46; P=.003), and blood sugar testing (mean −2.15, 95% CI −3.47 to −0.83; P=.003).

Conclusions

This study provides preliminary data for a large-scale appropriately powered randomized controlled trial to examine a culturally tailored lifestyle intervention in African Americans with type 2 diabetes mellitus and CKD in order to improve clinical, knowledge, self-care, and behavior outcomes in this population.

Anxiety during the Pandemic: Racial and ethnic differences in the trajectory of fear

BACKGROUND

In addition to the threat of serious illness, COVID-19 brought abrupt changes in lifestyle resulting in widespread fear among many Americans. This study examines the evolution of anxiety over the first months of the COVID-19 pandemic, testing for differential experiences among vulnerable populations.

METHODS

Phase 1 of the Census Bureau's Household Pulse Survey details the frequency of anxiety among a nationally representative sample of adults from April 23, 2020 through July 21, 2020. Negative binomial regression assessed differences in the frequency of anxiety among demographic, income, health and employment status cohorts. Propensity score matching to the 2019 National Health Interview Survey allowed previous anxiety and health status to be included in the model.

RESULTS

Anxiety frequency for 944,719 individuals was observed over three months. Whites, blacks and Hispanics showed increasing frequency of anxiety over the time period, particularly blacks. Prior to COVID-19, 13% of respondents reported regular or semiregular anxiety, compared to 25-35% during the pandemic. Regression analysis suggests that frequent anxiety was highly and positively correlated with COVID-19 case fatality rate and higher levels of frequency were observed among those with poor health, incomes below $25,000, and without paid employment.

LIMITATIONS

Causal inference was not able to be investigated due to the cross-sectional study design.

CONCLUSIONS

While blacks showed lower levels of anxiety initially, the proportion of the population experiencing regular anxiety increased nearly 20% over the first months of the COVID-19 pandemic. This rapid increase in anxiety could be due to inequity in health and economic outcomes among blacks.

Medicaid Expansion and Incidence of Kidney Failure among Nonelderly Adults

BACKGROUND

Low-income individuals without health insurance have limited access to health care. Medicaid expansions may reduce kidney failure incidence by improving access to chronic disease care.

METHODS

Using a difference-in-differences analysis, we examined the association between Medicaid expansion status under the Affordable Care Act (ACA) and the kidney failure incidence rate among all nonelderly adults, aged 19-64 years, in the United States, from 2012 through 2018. We compared changes in kidney failure incidence in states that implemented Medicaid expansions with concurrent changes in nonexpansion states during pre-expansion, early postexpansion (years 2 and 3 postexpansion), and later postexpansion (years 4 and 5 postexpansion).

RESULTS

The unadjusted kidney failure incidence rate increased in the early years of the study period in both expansion and nonexpansion states before stabilizing. After adjustment for population sociodemographic characteristics, Medicaid expansion status was associated with 2.20 fewer incident cases of kidney failure per million adults per quarter in the early postexpansion period (95% CI, -3.89 to -0.51) compared with nonexpansion status, a 3.07% relative reduction (95% CI, -5.43% to -0.72%). In the later postexpansion period, Medicaid expansion status was not associated with a statistically significant change in kidney failure incidence (-0.56 cases per million per quarter; 95% CI, -2.71 to 1.58) compared with nonexpansion status and the pre-expansion time period.

CONCLUSIONS

The ACA Medicaid expansion was associated with an initial reduction in kidney failure incidence among the entire, nonelderly, adult population in the United States; but the changes did not persist in the later postexpansion period. Further study is needed to determine the long-term association between Medicaid expansion and changes in kidney failure incidence.

International Society of Nephrology Global Kidney Health Atlas: structures, organization, and services for the management of kidney failure in North America and the Caribbean

The International Society of Nephrology established the Global Kidney Health Atlas project to define the global capacity for kidney replacement therapy and conservative kidney care, and this second iteration was to describe the availability, accessibility, quality, and affordability of kidney failure (KF) care worldwide. This report presents results for the International Society of Nephrology North America and the Caribbean region. Relative to other regions, the North America and Caribbean region had better infrastructure and funding for health care and more health care workers relative to the population. Various essential medicines were also more available and accessible. There was substantial variation in the prevalence of treated KF in the region, ranging from 137.4 per million population (pmp) in Jamaica to 2196 pmp in the United States. A mix of public and private funding systems cover costs for nondialysis chronic kidney disease care in 60% of countries and for dialysis in 70% of countries. Although the median number of nephrologists is 18.1 (interquartile range, 15.3-29.5) pmp, which is approximately twice the global median of 9.9 (interquartile range, 1.2-22.7) pmp, some countries reported shortages of other health care workers. Dialysis was available in all countries, but peritoneal dialysis was underutilized and unavailable in Barbados, Cayman Islands, and Turks and Caicos. Kidney transplantation was primarily available in Canada and the United States. Economic factors were the major barriers to optimal KF care in the Caribbean countries, and few countries in the region have chronic kidney disease-specific national health care policies. To address regional gaps in KF care delivery, efforts should be directed toward augmenting the workforce, improving the monitoring and reporting of kidney replacement therapy indicators, and implementing noncommunicable disease and chronic kidney disease-specific policies in all countries.

Association of Race/Ethnicity, Gender, and Socioeconomic Status With Sodium-Glucose Cotransporter 2 Inhibitor Use Among Patients With Diabetes in the US

IMPORTANCE

Sodium-glucose cotransporter 2 (SGLT2) inhibitors significantly reduce deaths from cardiovascular conditions, hospitalizations for heart failure, and progression of kidney disease among patients with type 2 diabetes. Black individuals have a disproportionate burden of cardiovascular and chronic kidney disease (CKD). Adoption of novel therapeutics has been slower among Black and female patients and among patients with low socioeconomic status than among White or male patients or patients with higher socioeconomic status.

OBJECTIVE

To assess whether inequities based on race/ethnicity, gender, and socioeconomic status exist in SGLT2 inhibitor use among patients with type 2 diabetes in the US.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study of commercially insured patients in the US was performed from October 1, 2015, to June 30, 2019, using the Optum Clinformatics Data Mart. Adult patients with a diagnosis of type 2 diabetes, including those with heart failure with reduced ejection fraction (HFrEF), atherosclerotic cardiovascular disease (ASCVD), or CKD, were evaluated in the analysis.

MAIN OUTCOMES AND MEASURES

Prescription of an SGLT2 inhibitor. Multivariable logistic regression models were used to assess the association of race/ethnicity, gender, and socioeconomic status with SGLT2 inhibitor use.

RESULTS

Of 934 737 patients with type 2 diabetes (mean [SD] age, 65.4 [12.9] years; 50.7% female; 57.6% White), 81 007 (8.7%) were treated with an SGLT2 inhibitor during the study period. Between 2015 and 2019, the percentage of patients with type 2 diabetes treated with an SGLT2 inhibitor increased from 3.8% to 11.9%. Among patients with type 2 diabetes and cardiovascular or kidney disease, the rate of SGLT2 inhibitor use increased but was lower than that among all patients with type 2 diabetes (HFrEF: 1.9% to 7.6%; ASCVD: 3.0% to 9.8%; CKD: 2.1% to 7.5%). In multivariable analyses, Black race (adjusted odds ratio [aOR], 0.83; 95% CI, 0.81-0.85), Asian race (aOR, 0.94; 95% CI, 0.90-0.98), and female gender (aOR, 0.84; 95% CI, 0.82-0.85) were associated with lower rates of SGLT2 inhibitor use, whereas higher median household income (≥$100 000: aOR, 1.08 [95% CI, 1.05-1.10]; $50 000-$99 999: aOR, 1.05 [95% CI, 1.03-1.07] vs <$50 000) was associated with a higher rate of SGLT2 inhibitor use. These results were similar among patients with HFrEF, ASCVD, and CKD.

CONCLUSIONS AND RELEVANCE

In this cohort study, use of an SGLT2 inhibitor treatment increased among patients with type 2 diabetes from 2015 to 2019 but remained low, particularly among patients with HFrEF, CKD, and ASCVD. Black and female patients and patients with low socioeconomic status were less likely to receive an SGLT2 inhibitor, suggesting that interventions to ensure more equitable use are essential to prevent worsening of well-documented disparities in cardiovascular and kidney outcomes in the US.

Racism and Kidney Health: Turning Equity Into a Reality

Kidney disease continues to manifest stark racial inequities in the United States, revealing the entrenchment of racism and bias within multiple facets of society, including in our institutions, practices, norms, and beliefs. In this perspective, we synthesize theory and evidence to describe why an understanding of race and racism is integral to kidney care, providing examples of how kidney health disparities manifest interpersonal and structural racism. We then describe racialized medicine and "colorblind" approaches as well as their pitfalls, offering in their place suggestions to embed antiracism and an "equity lens" into our practice. We propose examples of how we can enhance kidney health equity by enhancing our structural competency, using equity-focused race consciousness, and centering investigation and solutions around the needs of the most marginalized. To achieve equitable outcomes for all, our medical institutions must embed antiracism and equity into all aspects of advocacy, policy, patient/community engagement, educational efforts, and clinical care processes. Organizations engaged in kidney care should commit to promoting structural equity and eliminating potential sources of bias across referral practices, guidelines, research agendas, and clinical care. Kidney care providers should reaffirm our commitment to structurally competent patient care and educational endeavors in which empathy and continuous self-education about social drivers of health and inequity, racism, and bias are integral. We envision a future in which kidney health equity is a reality for all. Through bold collective and sustained investment, we can achieve this critical goal.

Religion, Spirituality, and Risk of End-Stage Kidney Disease Among Adults of Low Socioeconomic Status in the Southeastern United States

BACKGROUND

Religiosity, encompassing spirituality and religious practices, is associated with reduced disease incidence among individuals of low socioeconomic status and who self-identify as Black. We hypothesized that religiosity associates with reduced end-stage kidney disease (ESKD) risk among Black but not White adults of low socioeconomic status.

DESIGN

Cox models of religiosity and ESKD risk in 76,443 adults.

RESULTS

Black adults reporting high spirituality had reduced ESKD risk after adjusting for demographic characteristics [Hazard Ratio (HR) .82 (95% Confidence Interval (CI)) (.69-.98)], depressive symptoms, social support, and tobacco use [HR .81 (CI .68-.96)]. When clinical covariates were added, associations between spirituality and ESKD were slightly attenuated and lost significance [HR .85 (CI .68-1.06)]. Associations were not demonstrated among White adults.

CONCLUSIONS

Spirituality associates with reduced ESKD risk among Black adults of low socioeconomic status independent of demographic, psychosocial, and behavioral characteristics. Effect modification by race was not statistically significant.

Sex differences in chronic kidney disease awareness among US adults, 1999 to 2018

BACKGROUND

Chronic kidney disease (CKD) is less prevalent among men than women, but more men than women initiate kidney replacement therapy. Differences in CKD awareness may contribute to this gender gap, which may further vary by race/ethnicity. We aimed to investigate trends in CKD awareness and the association between individual characteristics and CKD awareness among US men versus women.

METHODS AND FINDINGS

We conducted a serial, cross-sectional analysis of 10 cycles (1999-2018) from the National Health and Nutrition Examination Survey (NHANES). Adult participants with CKD stages G3-G5 (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73m2) were included, unless they were on dialysis or medical information was missing. Serum creatinine was measured during NHANES medical exams. CKD stage was classified by eGFR, based on the CKD-EPI formula. CKD awareness was assessed with the question: "Have you ever been told by a health care professional you had weak or failing kidneys", asked in standardized NHANES questionnaires on each survey. Using logistic regression models, we evaluated the association between sex and CKD awareness, adjusting for potential confounders including age, race/ethnicity and comorbidities. We stratified CKD awareness by 5 pre-defined calendar-year periods and conducted all analyses for the complete study population as well as the Caucasian and African American subpopulations. We found that among 101871 US persons participating in NHANES, 4411 (2232 women) had CKD in stages G3-G5. These participants were, on average, 73±10 years old, 25.3% reported diabetes, 78.0% reported hypertension or had elevated blood pressure during medical examinations and 39.8% were obese (percentages were survey-weighted). CKD awareness was more prevalent among those with higher CKD stage, younger age, diabetes, hypertension and higher body mass index. CKD awareness was generally low (<22.5%), though it increased throughout the study period, remaining consistently higher among men compared to women, with a decreasing gender gap over time (adjusted odds ratio [men-to-women] for CKD awareness = 2.71 [1.31-5.64] in period 1; = 1.32 [0.82-2.12] in period 5). The sex difference in CKD awareness was smaller in African American participants, in whom CKD awareness was generally higher. Using serum creatinine rather than eGFR as the CKD-defining exposure, CKD awareness increased with rising serum creatinine, in a close to identical fashion among both sexes during 1999-2008, while during 2009-2018, CKD awareness among women increased earlier than among men (i.e. with lower serum creatinine levels).

CONCLUSIONS

CKD awareness is lower among US women than men. The narrowing gap between the sexes in more recent years and the results on CKD awareness by serum creatinine indicate that health care professionals have previously been relying on serum creatinine to inform patients about their condition, but in more recent years have been using eGFR, which accounts for women's lower serum creatinine levels due to their lower muscle mass. Additional efforts should be made to increase CKD awareness among both sexes.

Association of Educational Attainment With Incidence of CKD in Young Adults

Introduction

Chronic kidney disease (CKD) is greatly affected by social determinants of health. Whether low educational attainment is associated with incident CKD in young adults is unclear.

Methods

We evaluated the association of education with incident CKD in 3139 Coronary Artery Risk Development in Young Adults participants. We categorized education into low (high school and less), medium (college), and high (master’s and professional studies) groups. Incident CKD was defined as new development of estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m² or urine albumin to creatinine ratio (ACR) ≥30 mg/g. Change in eGFR over 20 years was a secondary outcome.

Results

At baseline, mean age was 35.0 ± 3.6 years, 47% were Black, and 55% were women. Participants with lower educational attainment were less likely to have high income and health insurance and to engage in a healthy lifestyle. Over 20 years, 407 participants developed CKD (13%). Compared with individuals with low educational attainment, those with medium and high educational attainment had an unadjusted hazard ratios for CKD of 0.79 (95% confidence interval [CI] 0.65–0.97) and 0.44 (95% CI, 0.30–0.63), respectively. This association was no longer significant after adjusting for income, health insurance, lifestyle, and health status. Low educational attainment was significantly associated with a change in eGFR in crude and adjusted analyses, although the association was attenuated in the multivariable models (low: –0.83 [95% CI, –0.91 to –0.75], medium: –0.80 (95% CI, –0.95 to –0.64), and high: –0.70 (95% CI, –0.89 to –0.52) ml/min per 1.73 m² per yr).

Conclusions

Health care access, lifestyle, and comorbid conditions likely help explain the association between low educational attainment and incident CKD in young adults.

Dietary Total Antioxidant Capacity and Its Association with Renal Function and Progression of Chronic Kidney Disease in Older Adults: a Report from a Developing Country

While evidence exists for an association between the dietary total antioxidant capacity (DTAC), mortality, metabolic syndrome, and cardiovascular diseases, data about DTAC and renal function, and progression of chronic kidney disease (CKD) are scarce. This study aimed to determine the associations between DTAC, renal function, and progression of CKD in older adults. The present cross-sectional study consisted of 226 older adults aged ≥ 60 years old from five districts of Tehran, Iran. DTAC was estimated using the oxygen radical absorbance capacity (ORAC) method. Dietary intake, socio-demographic data, medical history, and anthropometric measurements were collected using a validated questionnaire. The estimated glomerular filtration rate (eGFR) was assessed from serum creatinine. Albumin to creatinine ratio (ACR) was calculated by dividing albumin concentration by creatinine concentration and reported as mg/g. The DTAC ranged from 112.8 to 2,553.9. Analyses indicated that DTAC was not associated with eGFR (p = 0.35) and ACR (p = 0.91) even after controlling for confounding variables. Additionally, in logistic regression, no association between eGFR < 60 mL/min/1.73 m² (p = 0.32) and ACR ≥ 30 mg/g (p = 0.32) with DTAC was observed, which was independent of confounding variables. We observed that more compliance with DTAC is not associated with renal function and CKD progression. Further studies are needed to confirm the findings of the present study in larger samples on different populations.

Increased Incidence of Chronic Kidney Injury in African Americans Following Cardiac Transplantation

OBJECTIVES

This study examined whether African American race was associated with an elevated risk of chronic kidney disease (CKD) post-cardiac transplantation.

BACKGROUND

CKD often occurs after cardiac transplantation and may require renal replacement therapy (RRT) or renal transplant. African American patients have a higher risk for kidney disease as well as worse post-cardiac transplant morbidity and mortality. It is unclear, however, if there is a propensity for African Americans to develop CKD after cardiac transplant.

METHODS

The Institutional Review Board of Columbia University Medical Center approved the retrospective study of 151 adults (57 African American and 94 non-African American) who underwent single-organ heart transplant from 2013 to 2016. The primary outcome was a decrease in estimated glomerular filtration rate (eGFR), development of CKD, and end-stage renal disease (ESRD) requiring RRT after 2 years.

RESULTS

African American patients had a significant decline in eGFR post-cardiac transplant compared to non-African American patients (- 34 ± 6 vs. - 20 ± 4 mL/min/1.73 m2, p < 0.0006). African American patients were more likely to develop CKD stage 2 or worse (eGFR < 90 mL/min/1.73 m2) than non-African American patients (81% vs. 59%, p < 0.0005).

CONCLUSIONS

This is the first study to report that African American patients are at a significantly higher risk for eGFR decline and CKD at 2 years post-cardiac transplant. Future investigation into risk reduction is necessary for this patient population.

Epigenome-wide association study identifies DNA methylation sites associated with target organ damage in older African Americans

Target organ damage (TOD) manifests as vascular injuries in the body organ systems associated with long-standing hypertension. DNA methylation in peripheral blood leukocytes can capture inflammatory processes and gene expression changes underlying TOD. We investigated the association between epigenome-wide DNA methylation and five measures of TOD (estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (UACR), left ventricular mass index (LVMI), relative wall thickness (RWT), and white matter hyperintensity (WMH)) in 961 African Americans from hypertensive sibships. A multivariate (multi-trait) model of eGFR, UACR, LVMI, and RWT identified seven CpGs associated with at least one of the traits (cg21134922, cg04816311 near C7orf50, cg09155024, cg10254690 near OAT, cg07660512, cg12661888 near IFT43, and cg02264946 near CATSPERD) at FDR q < 0.1. Adjusting for blood pressure, body mass index, and type 2 diabetes attenuated the association for four CpGs. DNA methylation was associated with cis-gene expression for some CpGs, but no significant mediation by gene expression was detected. Mendelian randomization analyses suggested causality between three CpGs and eGFR (cg04816311, cg10254690, and cg07660512). We also assessed whether the identified CpGs were associated with TOD in 614 African Americans in the Hypertension Genetic Epidemiology Network (HyperGEN) study. Out of three CpGs available for replication, cg04816311 was significantly associated with eGFR (p = 0.0003), LVMI (p = 0.0003), and RWT (p = 0.002). This study found evidence of an association between DNA methylation and TOD in African Americans and highlights the utility of using a multivariate-based model that leverages information across related traits in epigenome-wide association studies.

Area Deprivation and Risk of Death and CKD Progression: Long-Term Cohort Study in Patients under Unrestricted Nephrology Care

BACKGROUND

Area deprivation index (ADI) associates with prognosis in non-dialysis CKD. However, no study has evaluated this association in CKD patients under unrestricted nephrology care.

METHODS

We performed a long-term prospective study to assess the role of deprivation in CKD progression and mortality in stage 1-4 CKD patients under regular nephrology care, living in Naples (Italy). We used ADI calculated at census block levels, standardized to mean values of whole population in Naples, and linked to patients by georeference method. After 12 months of "goal-oriented" nephrology treatment, we compared the risk of death or composite renal outcomes (end-stage kidney disease or doubling of serum creatinine) in the tertiles of standardized ADI. Estimated glomerular filtration rate (eGFR) decline was evaluated by mixed effects model for repeated eGFR measurements.

RESULTS

We enrolled 715 consecutive patients (age: 64 ± 15 years; 59.1% males; eGFR: 49 ± 22 mL/min/1.73 m2). Most (75.2%) were at the lowest national ADI quintile. At referral, demographic, clinical, and therapeutic features were similar across ADI tertiles; after 12 months, treatment intensification allowed better control of hypertension, proteinuria, hypercholesterolaemia, and anaemia with no difference across ADI tertiles. During the subsequent long-term follow-up (10.5 years [interquartile range 8.2-12.6]), 166 renal events and 249 deaths were registered. ADI independently associated with all-cause death (p for trend = 0.020) and non-cardiovascular (CV) mortality (p for trend = 0.045), while CV mortality did not differ (p for trend = 0.252). Risk of composite renal outcomes was similar across ADI tertiles (p for trend = 0.467). The same held true for eGFR decline (p for trend = 0.675).

CONCLUSIONS

In CKD patients under regular nephrology care, ADI is not associated with CKD progression, while it is associated with all-cause death due to an excess of non-CV mortality.

Obstructive Sleep Apnea, Other Sleep Characteristics, and Risk of CKD in the Atherosclerosis Risk in Communities Sleep Heart Health Study

BACKGROUND

Obstructive sleep apnea may be associated with development of CKD through hypoxia, inflammation, and oxidative stress. Individuals with this sleep disorder are also at increased risk for established CKD risk factors, including obesity, hypertension, and type 2 diabetes.

METHODS

We examined the association between obstructive sleep apnea, other sleep characteristics, and risk of incident CKD (stage 3 or higher) in 1525 participants (mean age, 62.5 years; 52.4% women) in the Atherosclerosis Risk in Communities (ARIC) study who completed in-home polysomnography assessments. We used the apnea-hypopnea index (events per hour) to define obstructive sleep apnea severity (normal, <5.0; mild, 5.0-14.9; moderate, 15.0-29.9; and severe, ≥30.0) and defined incident CKD (stage 3 or higher) as eGFR<60 ml/min per 1.73 m² and ≥25% decline from baseline, CKD-related hospitalization or death, or ESKD. Cox proportional hazards regression was used to estimate obstructive sleep apnea severity with risk of incident CKD, adjusting for demographics, lifestyle behaviors, and cardiometabolic conditions.

RESULTS

During 19 years (median) of follow-up, 461 CKD events occurred. After adjustment for demographics and lifestyle behaviors, severe obstructive sleep apnea associated with increased risk of CKD (hazard ratio [HR], 1.51; 95% confidence interval [95% CI], 1.08 to 2.10), which was attenuated after adjustment for body mass index (HR, 1.07; 95% CI, 0.75 to 1.52). No other sleep characteristics associated with incident CKD.

CONCLUSIONS

We found a link between obstructive sleep apnea and an elevated risk of stage 3 CKD or higher, but this association was no longer significant after adjusting for obesity, a risk factor for both conditions. Given the high prevalence of obstructive sleep apnea and CKD among adults, further investigation is warranted.

Neighborhood Environment Characteristics and Control of Hypertension and Diabetes in a Primary Care Patient Sample

BACKGROUND

Hypertension control and diabetes control are important for reducing cardiovascular disease burden. A growing body of research suggests an association between neighborhood environment and hypertension or diabetes control among patients engaged in clinical care.

OBJECTIVE

To investigate whether neighborhood conditions (i.e., healthy food availability, socioeconomic status (SES), and crime) were associated with hypertension and diabetes control.

DESIGN

Cross-sectional analyses using electronic medical record (EMR) data, U.S. Census data, and secondary data characterizing neighborhood food environments. Multivariate logistic regression analyses adjusted for potential confounders. Analyses were conducted in 2017.

PARTICIPANTS

Five thousand nine hundred seventy adults receiving primary care at three Baltimore City clinics in 2010-2011.

MAIN MEASURES

Census tract-level neighborhood healthy food availability, neighborhood SES, and neighborhood crime. Hypertension control defined as systolic blood pressure < 140 mmHg and diastolic blood pressure < 90 mmHg. Diabetes control defined as HgbA1c < 7.

KEY RESULTS

Among patients with hypertension, neighborhood conditions were not associated with lower odds of blood pressure control after accounting for patient and physician characteristics. However, among patients with diabetes, in fully adjusted models accounting for patient and physician characteristics, we found that patients residing in neighborhoods with low and moderate SES had reduced odds of diabetes control (OR = 0.74 (95% CI = 0.57-0.97) and OR = 0.75 (95% CI = 0.57-0.98), respectively) compared to those living in high-SES neighborhoods.

CONCLUSIONS

Neighborhood disadvantage may contribute to poor diabetes control among patients in clinical care. Community-based chronic disease care management strategies to improve diabetes control may be optimally effective if they also address neighborhood SES among patients engaged in care.

Awareness and Discussions About Chronic Kidney Disease Among African-Americans with Chronic Kidney Disease and Hypertension: a Mixed Methods Study

BACKGROUND

Routine primary care visits provide an educational opportunity for African-Americans with chronic kidney disease (CKD) and CKD risk factors such as hypertension. The nature of patient-physician discussions about CKD and their impact on CKD awareness in this population have not been well explored.

OBJECTIVE

To characterize patient CKD awareness and discussions about CKD between patients and primary care physicians (PCPs).

DESIGN

Mixed methods study.

PATIENTS

African-American patients with uncontrolled hypertension (≥ 140/90 mmHg) and CKD (albuminuria or eGFR < 60 ml/min/1.73 m2) recruited from an urban primary care clinic.

MAIN MEASURES

We assessed patient CKD awareness with questionnaires and audio-recorded patients-PCP discussions during a routine visit. We characterized discussions and used multivariate regression analysis to identify independent patient and visit predictors of CKD awareness or CKD discussions.

RESULTS

Among 48 African-American patients with uncontrolled hypertension and CKD, 29% were aware of their CKD. After adjustment, CKD awareness was associated with moderate-severe CKD (stages 3-4) (vs. mild CKD [stages 1-2]) (prevalence ratio [PR] 2.82; 95% CI 1.18-6.78) and inversely associated with diabetes (vs. without diabetes) (PR 0.28; 95% CI 0.10-0.75). CKD discussions occurred in 30 (63%) visits; most focused on laboratory assessment (n = 23, 77%) or risk factor management to delay CKD progression (n = 19, 63%). CKD discussions were associated with moderate-severe CKD (vs. mild CKD) (PR 1.57; 95% CI 1.04-2.36) and diabetes (vs. without diabetes) (PR 1.42; 95% CI 1.09-1.85), and inversely associated with uncontrolled hypertension (vs. controlled) (PR 0.58; 95% CI 0.92-0.89). In subgroup analysis, follow-up CKD awareness did not change by presence or absence of CKD discussion (10.5% vs. 7.7%, p = 0.8).

CONCLUSIONS

In patients at risk of CKD progression, few were aware of CKD, and CKD discussions were not associated with CKD awareness. More resources may be needed to enhance the clarity of clinical messages regarding CKD and its significance for patients' health.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01902719.

Detecting Lifestyle Risk Factors for Chronic Kidney Disease With Comorbidities: Association Rule Mining Analysis of Web-Based Survey Data

Background

The rise in the number of patients with chronic kidney disease (CKD) and consequent end-stage renal disease necessitating renal replacement therapy has placed a significant strain on health care. The rate of progression of CKD is influenced by both modifiable and unmodifiable risk factors. Identification of modifiable risk factors, such as lifestyle choices, is vital in informing strategies toward renoprotection. Modification of unhealthy lifestyle choices lessens the risk of CKD progression and associated comorbidities, although the lifestyle risk factors and modification strategies may vary with different comorbidities (eg, diabetes, hypertension). However, there are limited studies on suitable lifestyle interventions for CKD patients with comorbidities.

Objective

The objectives of our study are to (1) identify the lifestyle risk factors for CKD with common comorbid chronic conditions using a US nationwide survey in combination with literature mining, and (2) demonstrate the potential effectiveness of association rule mining (ARM) analysis for the aforementioned task, which can be generalized for similar tasks associated with noncommunicable diseases (NCDs).

Methods

We applied ARM to identify lifestyle risk factors for CKD progression with comorbidities (cardiovascular disease, chronic pulmonary disease, rheumatoid arthritis, diabetes, and cancer) using questionnaire data for 450,000 participants collected from the Behavioral Risk Factor Surveillance System (BRFSS) 2017. The BRFSS is a Web-based resource, which includes demographic information, chronic health conditions, fruit and vegetable consumption, and sugar- or salt-related behavior. To enrich the BRFSS questionnaire, the Semantic MEDLINE Database was also mined to identify lifestyle risk factors.

Results

The results suggest that lifestyle modification for CKD varies among different comorbidities. For example, the lifestyle modification of CKD with cardiovascular disease needs to focus on increasing aerobic capacity by improving muscle strength or functional ability. For CKD patients with chronic pulmonary disease or rheumatoid arthritis, lifestyle modification should be high dietary fiber intake and participation in moderate-intensity exercise. Meanwhile, the management of CKD patients with diabetes focuses on exercise and weight loss predominantly.

Conclusions

We have demonstrated the use of ARM to identify lifestyle risk factors for CKD with common comorbid chronic conditions using data from BRFSS 2017. Our methods can be generalized to advance chronic disease management with more focused and optimized lifestyle modification of NCDs.

How does alcohol access affect transitional adults' healthy dietary behaviors?

Despite the rich evidence of the negative effects of alcohol on health, educational, and labor market outcomes, less is known about whether or how lowering the cost of accessing alcohol affects youths' healthy dietary behaviors. Our study addresses this gap by employing individual-level data from the National Longitudinal Survey of Youth 1997 (NLSY97). Exploiting the age cutoff in the US minimum legal drinking age law, we find that the transition to the age of 21 coincides with a discontinuous increase in the consumption of fruit and vegetables among the overall NLSY97 sample. One possible explanation for this seemingly counterintuitive result is that some youths re-optimized in response to an exogenous reduction in the cost of alcohol access. We separated the results by drinking status and gender, scrutinized the drinking subsample, and found suggestive evidence in support of this hypothesis. We also examined different sociodemographic subgroups to better understand the heterogeneous local average treatment effects of the universal MLDA policy.

hs-CRP Is Associated With Incident Diabetic Nephropathy: Findings From the Jackson Heart Study

OBJECTIVE

African Americans (AA) suffer disproportionately from diabetic nephropathy (DN). C-reactive protein (CRP) has been associated with prevalent DN, but its association with incident DN in AA is unknown. We examined hs-CRP and incident DN in AA.

RESEARCH DESIGN AND METHODS

We conducted a longitudinal analysis of data from exams 1, 2, and 3 in 4,043 eligible Jackson Heart Study (JHS) participants. Participants with DN or without hs-CRP at exam 1 were excluded. Incident DN was defined as urinary albumin-to-creatinine ratio (ACR) >30 mg/g or self-reported dialysis/transplantation and type 2 diabetes mellitus (DM) or HbA1c >6.5% by exam 2 or 3 among participants free of DN at exam 1. Kaplan-Meier curves examined DN event-free survival probability by hs-CRP. With Cox proportional hazards regression we estimated hazard ratios (HRs) and 95% CI for DN by hs-CRP tertiles, adjusting for demographics and clinical and laboratory data.

RESULTS

During 7.8 years of median follow-up time, participants who developed DN had significantly higher baseline hs-CRP, age, fasting glucose, triglycerides, ACR, systolic blood pressure, waist circumference, and duration of DM (P < 0.05). The overall incident rate of DN was 7.9%. The mean time to incident DN was shorter for participants with hs-CRP in the high tertile (>4.24 mg/L) than in the low tertile (<1.46 mg/L); P < 0.001. Participants with high hs-CRP had higher incidence of DN (HR 2.34, 95% CI 1.04-5.24) versus the reference group.

CONCLUSIONS

Inflammation, as measured by hs-CRP levels, may be associated with incident DN in AA. Further studies are warranted to replicate and elucidate the basis for this association.

Patient Navigation: Addressing Social Challenges in Dialysis Patients

Members of racial and ethnic minority groups make up nearly 50% of US patients with end-stage kidney disease and face a disproportionate burden of socioeconomic challenges (ie, low income, job insecurity, low educational attainment, housing instability, and communication challenges) compared with non-Hispanic whites. Patients with end-stage kidney disease who face social challenges often have poor patient-centered and clinical outcomes. These challenges may have a negative impact on quality-of-care performance measures for dialysis facilities caring for primarily minority and low-income patients. One path toward improving outcomes for this group is to develop culturally tailored interventions that provide individualized support, potentially improving patient-centered, clinical, and health system outcomes by addressing social challenges. One such approach is using community-based culturally and linguistically concordant patient navigators, who can serve as a bridge between the patient and the health care system. Evidence points to the effectiveness of patient navigators in the provision of cancer care and, to a lesser extent, caring for people with chronic kidney disease and those who have undergone kidney transplantation. However, little is known about the effectiveness of patient navigators in the care of patients with kidney failure receiving dialysis, who experience a number of remediable social challenges.

Kidney Disease in African American Children: Biological and Nonbiological Disparities

Pediatric-onset chronic kidney disease (CKD) is as relevant to adults as it is to children. Congenital anomalies of the kidney and urinary tract may have a significant impact on health from birth or during childhood or may not manifest until adulthood. Many acquired kidney diseases start to appear in late childhood and adolescence. The propensity for more rapid progression of CKD to end-stage kidney disease in adults of African ancestry, as well as disparities in access to kidney transplantation and allograft longevity, have been well documented for decades. Similar disparate patterns are seen in children, and we now know that there are a range of biological and nonbiological risk factors for the development and progression of CKD in people of African descent that are pertinent to CKD in children. In some cases, it is unclear whether there are effective potential interventions, whereas in other situations, there are opportunities to improve outcomes.

Interventions to Improve Blood Pressure Control Among Socioeconomically Disadvantaged Patients With CKD: Kidney Awareness Registry and Education Pilot Randomized Controlled Trial

RATIONALE & OBJECTIVE

Sustainable interventions that enhance chronic kidney disease (CKD) management are not often studied in safety-net primary care, in which populations bear a disproportionate burden of disease and experience translational gaps between research and practice. We tested the feasibility of implementing and the impact of 2 technology-enhanced interventions designed to enhance CKD care delivery.

STUDY DESIGN

A 2×2 randomized controlled pilot trial.

SETTING & PARTICIPANTS

Primary care provider teams (n = 6) and 137 patients with CKD aged 18 to 75 years from 2 safety-net primary care clinics, 2013 to 2015.

INTERVENTIONS

Primary care provider teams were randomly assigned to access a CKD registry with point-of-care notifications and quarterly feedback or a usual-care registry for 12 months. Patients within provider teams were randomly assigned to participate in a CKD self-management support program or usual care for 12 months.

OUTCOMES

We examined recruitment, randomization, and participation in each intervention. We also examined the impact of each intervention and their combination on change in systolic blood pressure (SBP), albuminuria, and patient self-reported behavioral measures after 12 months.

RESULTS

Among potentially eligible patients identified using the electronic health record, 24% were eligible for study participation, of whom 35% (n = 137) were enrolled. Mean age was 55 years, 41% were non-English speaking, and 93% were of racial/ethnic minority. Mean baseline estimated glomerular filtration rate was 70.5 (SD = 30.3) mL/min/1.73 m2; mean baseline SBP was 131 (SD = 21.8) mm Hg. Nearly 90% of clinicians reported that the CKD registry influenced their CKD management. More than 95% of patients randomly assigned to CKD self-management support engaged regularly with the intervention. Estimated changes in SBP over 1 year were nonstatistically different in each of the 3 intervention groups compared with usual care: (usual care: 0.5 [95% CI, -5.2 to 6.3] mm Hg; CKD registry only: -5.4 [95% CI, -12.2 to 1.4] mm Hg; CKD self-management support only: -6.4 [95% CI, -13.7 to 1.0] mm Hg; and CKD registry plus CKD self-management support: -0.5 [-5.5 to 4.5] mm Hg), though differences were larger among those with baseline SBPs > 140/90 mm Hg. Decreases in albuminuria were similarly nonstatistically different in each of the intervention groups compared with usual care. No differences were observed in patient self-reported behaviors.

LIMITATIONS

Single health system.

CONCLUSIONS

Patient and provider interventions to improve CKD care are feasible to implement in low-income settings with promising results among those with uncontrolled blood pressure.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

TRIAL REGISTRATION

ClinicalTrials.gov, number: NCT01530958.

A collaborative, individual-level analysis compared longitudinal outcomes across the International Network of Chronic Kidney Disease (iNETCKD) cohorts

Rates of chronic kidney disease (CKD) progression, end stage kidney disease (ESKD), all-cause mortality, and cardiovascular (CVD) events among individuals with CKD vary widely across countries. Well-characterized demographic, comorbidity, and laboratory markers captured for prospective cohorts may explain, in part, such differences. To investigate whether core characteristics of individuals with CKD explain differences in rates of outcomes, we conducted an individual-level analysis of eight studies that are part of iNET-CKD, an international network of CKD cohort studies. Overall, the rate of CKD progression was 40 events/1000 person-year (95% confidence interval 39 - 41), 28 (27 - 29) for ESKD, 41 (40 - 42) for death, and 29 (28 - 30) for CVD events. However, standardized rates were highly heterogeneous across studies (over 92.5%). Interactions by study group on the association between baseline characteristics and outcomes were then identified. For example, the adjusted hazard ratio for CKD progression was 0.44 (95% confidence interval 0.35 - 0.56) for women vs. men among the Japanese (CKD-JAC), while it was 0.66 (0.59 - 0.75) among the Uruguayan (NRHP). The adjusted hazard ratio for ESKD was 2.02 (95% CI 1.88 - 2.17) per 10 units lower baseline eGFR among Americans (CRIC), while it was 3.01 (2.57 - 3.53) among Canadians (CanPREDDICT) (significant interaction for comparisons across all studies). The risks of CKD progression, ESKD, death, and CVD vary across countries even after accounting for the distributions of age, sex, comorbidities, and laboratory markers. Thus, our findings support the need for a better understanding of specific factors in different populations that explain this variation.

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.

Association of APOL1 Risk Alleles With Cardiovascular Disease in Blacks in the Million Veteran Program

BACKGROUND

Approximately 13% of black individuals carry 2 copies of the apolipoprotein L1 (APOL1) risk alleles G1 or G2, which are associated with 1.5- to 2.5-fold increased risk of chronic kidney disease. There have been conflicting reports as to whether an association exists between APOL1 risk alleles and cardiovascular disease (CVD) that is independent of the effects of APOL1 on kidney disease. We sought to test the association of APOL1 G1/G2 alleles with coronary artery disease, peripheral artery disease, and stroke among black individuals in the Million Veteran Program.

METHODS

We performed a time-to-event analysis of retrospective electronic health record data using Cox proportional hazard and competing-risks Fine and Gray subdistribution hazard models. The primary exposure was APOL1 risk allele status. The primary outcome was incident coronary artery disease among individuals without chronic kidney disease during the 12.5-year follow-up period. We separately analyzed the cross-sectional association of APOL1 risk allele status with lipid traits and 115 cardiovascular diseases using phenome-wide association.

RESULTS

Among 30 903 black Million Veteran Program participants, 3941 (13%) carried the 2 APOL1 risk allele high-risk genotype. Individuals with normal kidney function at baseline with 2 risk alleles had slightly higher risk of developing coronary artery disease compared with those with no risk alleles (hazard ratio, 1.11 [95% CI, 1.01-1.21]; P=0.039). Similarly, modest associations were identified with incident stroke (hazard ratio, 1.20 [95% CI, 1.05-1.36; P=0.007) and peripheral artery disease (hazard ratio, 1.15 [95% CI, 1.01-1.29l; P=0.031). When both cardiovascular and renal outcomes were modeled, APOL1 was strongly associated with incident renal disease, whereas no significant association with the CVD end points could be detected. Cardiovascular phenome-wide association analyses did not identify additional significant associations with CVD subsets.

CONCLUSIONS

APOL1 risk variants display a modest association with CVD, and this association is likely mediated by the known APOL1 association with chronic kidney disease.

Clair Russell J, Pendergast J, Bhavsar N, Scialla J, Tyson CC, Wang W, Min YI, Young B, Boulware LE, Diamantidis CJ. Association of functional and structural social support with chronic kidney disease among African Americans: the Jackson Heart Study

BACKGROUND

There is limited evidence on the relationship between social support and renal outcomes in African Americans. We sought to determine the association of social support with prevalent chronic kidney disease (CKD) and kidney function decline in an African American cohort. We also examined whether age modifies the association between social support and kidney function decline.

METHODS

We identified Jackson Heart Study (JHS) participants with baseline (Exam in 2000-2004) functional and structural social support data via the Interpersonal Support Evaluation List (ISEL) and social network size questions, respectively. With ISEL as our primary exposure variable, we performed multivariable regression models to evaluate the association between social support and prevalent CKD [estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2 or urine albumin-creatinine ratio (ACR) ≥30 mg/g], eGFR decline, and rapid renal function decline (RRFD) (> 30% decrease in eGFR over approximately 10 years). All models were adjusted for baseline sociodemographics, diabetes, hypertension, smoking status, and body mass index; models for eGFR decline and RRFD were additionally adjusted for eGFR and ACR. In models for eGFR decline, we assessed for interaction between age and social support. For secondary analyses, we replaced ISEL with its individual domains (appraisal, belonging, self-esteem, and tangible) and social network size in separate models as exposure variables.

RESULTS

Of 5301 JHS participants, 4015 (76%) completed the ISEL at baseline. 843 (21%) had low functional social support (ISEL score < 32). Participants with low (vs. higher) functional social support were more likely to have lower income (47% vs. 28%), be current or former tobacco users (39% vs. 30%), have diabetes (25% vs. 21%) or CKD (14% vs. 12%). After multivariable adjustment, neither ISEL or social network size were independently associated with prevalent CKD, eGFR decline, or RRFD. Of the ISEL domains, only higher self-esteem was associated with lower odds of prevalent CKD [OR 0.94 (95% CI 0.89-0.99)]. The associations between social support measures and eGFR decline were not modified by age.

CONCLUSIONS

In this African-American cohort, social support was not associated with prevalent CKD or kidney function decline. Further inquiry of self-esteem's role in CKD self-management and renal outcomes is warranted.

Association of Fitness With Racial Differences in Chronic Kidney Disease

INTRODUCTION

Non-white minorities are at higher risk for chronic kidney disease than non-Hispanic whites. Better cardiorespiratory fitness is associated with slower declines in estimated glomerular filtration rate and a lower incidence of chronic kidney disease. Little is known regarding associations of fitness with racial disparities in chronic kidney disease.

METHODS

A prospective cohort of 3,842 young adults without chronic kidney disease completed a maximal treadmill test at baseline in 1985-1986. Chronic kidney disease status was defined as estimated glomerular filtration rate of <60 mL/min/1.73 m² during 10-, 15-, 20-, 25-, and 30-year follow-up assessments (through 2006). Analyses were completed in 2019. Multivariable Cox models were used to determine hazard ratios and 95% CI for incidence of chronic kidney disease. Multivariable models included race, gender, age, field center, education, baseline estimated glomerular filtration rate, and time-varying covariates of healthy diet index, smoking status, alcohol intake, BMI, systolic blood pressure, and fasting glucose. Percent attenuation quantified the association of fitness to racial disparities in chronic kidney disease.

RESULTS

Chronic kidney disease incidence was higher among blacks (n=83/1,941, 1.61 per 1,000 person years) than whites (43/1,901, 0.82 per 1,000 person years). Every 1-minute shorter treadmill duration was associated with 1.14 (95% CI=1.04, 1.25) times higher risk of chronic kidney disease. Blacks were 1.72 (95% CI=1.13, 2.63) times more likely to develop chronic kidney disease compared with whites. The risk was reduced to 1.54 (95% CI=1.01, 2.39) with fitness added. This suggests that fitness is associated with 20.4% (95% CI=5.8, 43.0%) of the excess risk of chronic kidney disease attributable to race.

CONCLUSIONS

Low fitness is a modifiable factor that may contribute to the racial disparity in chronic kidney disease.

Long-term exposure to ambient air pollution and renal function in African Americans: the Jackson Heart Study

Renal dysfunction is prevalent in the US among African Americans. Air pollution is associated with renal dysfunction in mostly white American populations, but has not been studied among African Americans. We evaluated cross-sectional associations between 1-year and 3-year fine particulate matter (PM_2.5) and ozone (O₃) concentrations, and renal function among 5090 African American participants in the Jackson Heart Study. We used mixed-effect linear regression to estimate associations between 1-year and 3-year PM_2.5 and O₃ and estimated glomerular filtration rate (eGFR), urine albumin/creatinine ratio (UACR), serum creatinine, and serum cystatin C, adjusting for: sociodemographic factors, health behaviors, and medical history and accounting for clustering by census tract. At baseline, JHS participants had mean age 55.4 years, and 63.8% were female; mean 1-year and 3-year PM_2.5 concentrations were 12.2 and 12.4 µg/m³, and mean 1-year and 3-year O₃ concentrations were 40.2 and 40.7 ppb, respectively. Approximately 6.5% of participants had reduced eGFR (< 60 mL/min/1.73m²) and 12.7% had elevated UACR (> 30 mg/g), both indicating impaired renal function. Annual and 3-year O₃ concentrations were inversely associated with eGFR and positively associated with serum creatinine; annual and 3-year PM_2.5 concentrations were inversely associated with UACR. We observed impaired renal function associated with increased O₃ but not PM_2.5 exposure among African Americans.