CKD Progression and Mortality among Hispanics and Non-Hispanics

The Need for Culturally Tailored CKD Education in Older Latino Patients and Their Families

Older Latino adults (65+) comprise the fastest growing minoritized group among the older population in the US and experience a disproportionate burden of kidney failure as well as disparities in kidney care compared to non-Hispanic White individuals. Despite significant need and barriers uniquely faced by this population, few educational resources or decision aids are available to meet the language and cultural needs of Latino patients. Decision aids are designed to improve knowledge and empower individuals to engage in shared decision-making and have been shown to improve decisional quality and goal-concordant care among older patients with CKD. In this commentary, we examine the barriers faced by older Latino people with CKD who must make dialysis initiation decisions. We conclude that there is a need for culturally concordant decision aids tailored for older Latino patients with CKD to overcome barriers in access to care and improve patient-centered care for older Latino CKD patients.

Strategies to Guide Preemptive Waitlisting and Equity in Waittime Accrual by Race/Ethnicity

BACKGROUND

Use of eGFR to determine preemptive waitlisting eligibility may contribute to racial/ethnic disparities in access to waitlisting, which can only occur when the eGFR falls to ≤20 ml/min per 1.73 m 2 . Use of an alternative risk-based strategy for waitlisting may reduce these inequities ( e.g. , a kidney failure risk equation [KFRE] estimated 2-year risk of kidney failure) rather than the standard eGFR threshold for determining waitlist eligibility. Our objective was to model the amount of preemptive waittime that could be accrued by race and ethnicity, applying two different strategies to determine waitlist eligibility.

METHODS

Using electronic health record data, linear mixed models were used to compare racial/ethnic differences in preemptive waittime that could be accrued using two strategies: estimating the time between an eGFR ≤20 and 5 ml/min per 1.73 m 2 versus time between a 25% 2-year predicted risk of kidney failure (using the KFRE, which incorporates age, sex, albuminuria, and eGFR to provide kidney failure risk estimation) and eGFR of 5 ml/min per 1.73 m 2 .

RESULTS

Among 1290 adults with CKD stages 4-5, using the Chronic Kidney Disease Epidemiology Collaboration equation yielded shorter preemptive waittime between an eGFR of 20 and 5 ml/min per 1.73 m 2 in Black (-6.8 months; 95% confidence interval [CI], -11.7 to -1.9), Hispanic (-10.2 months; -15.3 to -5.1), and Asian/Pacific Islander (-10.3 months; 95% CI, -15.3 to -5.4) patients compared with non-Hispanic White patients. Use of a KFRE threshold to determine waittime yielded smaller differences by race and ethnicity than observed when using a single eGFR threshold, with shorter time still noted for Black (-2.5 months; 95% CI, -7.8 to 2.7), Hispanic (-4.8 months; 95% CI, -10.3 to 0.6), and Asian/Pacific Islander (-5.4 months; -10.7 to -0.1) individuals compared with non-Hispanic White individuals, but findings only met statistical significance criteria in Asian/Pacific Islander individuals. When we compared potential waittime availability using a KFRE versus eGFR threshold, use of the KFRE yielded more equity in waittime for Black ( P = 0.02), Hispanic ( P = 0.002), and Asian/Pacific Islander ( P = 0.002) patients.

CONCLUSIONS

Use of a risk-based strategy was associated with greater racial equity in waittime accrual compared with use of a standard single eGFR threshold to determine eligibility for preemptive waitlisting.

Prevalence of infertility and pregnancy loss among individuals with kidney disease in the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Hispanic/Latino individuals are less likely to receive optimal treatment for chronic kidney disease than non-Hispanic whites. This may be particularly detrimental for women of reproductive age as chronic kidney disease increases risk for infertility, menstrual irregularities, and pregnancy loss. While these maternal outcomes have been associated with advanced chronic kidney disease, their occurrence in early chronic kidney disease is unclear.

OBJECTIVES/DESIGN

Using baseline (2008-2011) and second study visit (2014-2017) data from the Hispanic Community Health Study/Study of Latinos, we retrospectively assessed the prevalence of chronic kidney disease as well as the association between chronic kidney disease and self-reported infertility, cessation of menses, hysterectomy, and nonviable pregnancy loss (experienced at less than 24 weeks gestation) in women of reproductive age (18-45 years).

METHODS

Multivariable survey logistic regression analyses determined the unadjusted and multivariable-adjusted prevalence odds ratios with 95% confidence intervals between chronic kidney disease and the separate outcomes.

RESULTS

Among 2589 Hispanic/Latino women included (mean age = 31.4 years), 4.6% were considered to have chronic kidney disease. In adjusted analyses, women with chronic kidney disease did not have a significantly increased odds of infertility (odds ratio = 1.02, 95% confidence interval = 0.42-2.49), cessation of menses (odds ratio = 1.25, 95% confidence interval = 0.52-3.04), or hysterectomy (odds ratio = 1.17, 95% confidence interval = 0.61-2.25) compared to those without chronic kidney disease. In those with chronic kidney disease, the adjusted odds of a nonviable pregnancy loss occurring after baseline visit were increased (odds ratio = 2.11, 95% confidence interval = 0.63-7.02) but not statistically significance.

CONCLUSION

The presence of early stage chronic kidney disease did not confer a significant risk of infertility, cessation of menses, or nonviable pregnancy loss.

Differences in Outcomes by Place of Origin among Hispanic Patients with Kidney Failure

SIGNIFICANCE STATEMENT

Hispanic patients are known to have a higher risk of kidney failure and lower rates of home dialysis use and kidney transplantation than non-Hispanic White patients. However, it is unknown whether these outcomes differ within the Hispanic community, which is heterogeneous in its members' places of origins. Using United States Renal Data System data, the authors found similar adjusted rates of home dialysis use for patients originating from places outside the United States and US-born Hispanic patients, whereas the adjusted risk of mortality and likelihood of transplantation differed depending on place (country or territory) of origin. Understanding the heterogeneity in kidney disease outcomes and treatment within the Hispanic community is crucial in designing interventions and implementation strategies to ensure that Hispanic individuals with kidney failure have equitable access to care.

BACKGROUND

Compared with non-Hispanic White groups, Hispanic individuals have a higher risk of kidney failure yet lower rates of living donor transplantation and home dialysis. However, how home dialysis, mortality, and transplantation vary within the Hispanic community depending on patients' place of origin is unclear.

METHODS

We identified adult Hispanic patients from the United States Renal Data System who initiated dialysis in 2009-2017. Primary exposure was country or territory of origin (the United States, Mexico, US-Puerto Rico, and other countries). We used logistic regression to estimate differences in odds of initiating home dialysis and competing risk models to estimate subdistribution hazard ratios (SHR) of mortality and kidney transplantation.

RESULTS

Of 137,039 patients, 44.4% were US-born, 30.9% were from Mexico, 12.9% were from US-Puerto Rico, and 11.8% were from other countries. Home dialysis rates were higher among US-born patients, but not significantly different after adjusting for demographic, medical, socioeconomic, and facility-level factors. Adjusted mortality risk was higher for individuals from US-Puerto Rico (SHR, 1.04; 95% confidence interval [CI], 1.01 to 1.08) and lower for Mexico (SHR, 0.80; 95% CI, 0.78 to 0.81) and other countries (SHR, 0.83; 95% CI, 0.81 to 0.86) compared with US-born patients. The adjusted rate of transplantation for Mexican or US-Puerto Rican patients was similar to that of US-born patients but higher for those from other countries (SHR, 1.22; 95% CI, 1.15 to 1.30).

CONCLUSIONS

Hispanic people from different places of origin have similar adjusted rates of home dialysis but different adjusted rates of mortality and kidney transplantation. Further research is needed to understand the mechanisms underlying these observed differences in outcomes.

The AKI-to-CKD Transition: The Role of Uremic Toxins

After acute kidney injury (AKI), renal function continues to deteriorate in some patients. In a pro-inflammatory and profibrotic environment, the proximal tubules are subject to maladaptive repair. In the AKI-to-CKD transition, impaired recovery from AKI reduces tubular and glomerular filtration and leads to chronic kidney disease (CKD). Reduced kidney secretion capacity is characterized by the plasma accumulation of biologically active molecules, referred to as uremic toxins (UTs). These toxins have a role in the development of neurological, cardiovascular, bone, and renal complications of CKD. However, UTs might also cause CKD as well as be the consequence. Recent studies have shown that these molecules accumulate early in AKI and contribute to the establishment of this pro-inflammatory and profibrotic environment in the kidney. The objective of the present work was to review the mechanisms of UT toxicity that potentially contribute to the AKI-to-CKD transition in each renal compartment.

Community-Engaged Research (CEnR) to Address Gaps in Chronic Kidney Disease Education among Underserved Latines-The CARE Study

Ensuring equitable chronic kidney disease (CKD) education for Latine patients with low health literacy and low English proficiency stands as a critical challenge, and the "Caridad Awareness and Education" (CARE) initiative represents our ongoing effort to address this imperative issue. In collaboration with twenty-three patients living with CKD, diabetes and/or hypertension and twelve trained Community Health Workers (CHWs) from diverse Latine subgroups, we conducted a research initiative funded by the National Kidney Foundation. Our primary objective was to co-design and test culturally tailored patient education materials (PEMs) for underserved Latine adults at risk for or diagnosed with CKD. We effectively integrated Community-Engaged Research (CEnR) principles with a Human-Centered Design (HCD) approach to create a range of CKD-PEM prototypes in Spanish. Patient preferences for printed educational materials were clear. They favored printed materials that incorporated visual content with concise text over digital, email, texts, or online resources and personalized phone outreach and the involvement of CHWs. Additionally, patients identified their unwavering commitment to their families as a forceful motivator for caring for their kidney health. Currently, a culturally and linguistically tailored CKD flipchart for one-on-one education, led by CHWs, is undergoing a pilot testing phase involving a sample of one hundred Latine patients at risk for or diagnosed with CKD. This innovative approach signifies a commitment to amplifying the insights and expertise of the Latine community afflicted by kidney health disparities, effectively embracing a CEnR to forge meaningful and impactful CKD-PEMs.

Finerenone in Hispanic Patients With CKD and Type 2 Diabetes: A Post Hoc FIDELITY Analysis

Rationale & Objective

In FIDELITY, finerenone improved cardiorenal outcomes in patients with chronic kidney disease (CKD) and type 2 diabetes. This analysis explores the efficacy and safety of finerenone in Hispanic patients.

Study Design

Post hoc analysis of the FIDELITY prespecified pooled analysis of the FIDELIO-DKD and FIGARO-DKD randomized control trials.

Setting & Participants

Patients with type 2 diabetes and CKD (urinary albumin-to-creatinine ratio [UACR] of ≥30 to <300 mg/g and estimated glomerular filtration rate [eGFR] of ≥25-≤90 mL/min/1.73 m2, or UACR of ≥300 to ≤5,000 and eGFR of ≥25 mL/min/1.73 m2) on optimized renin-angiotensin system blockade.

Intervention

Finerenone or placebo.

Outcomes

Cardiovascular composite (cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure); kidney composite (kidney failure, sustained ≥57% eGFR decline, or renal death); change in UACR.

Results

Of 13,026 patients, 2,099 (16.1%) self-identified as Hispanic. Median follow-up was 3.0 years. The cardiovascular composite outcome occurred in 10.0% of Hispanic patients receiving Finerenone and in 12.3% of Hispanic patients receiving placebo (HR, 0.80; 95% CI, 0.62-1.04). This was consistent with non-Hispanic patients (HR, 0.87; 95% CI, 0.79-0.97; Pinteraction= 0.59). The kidney composite outcome occurred in 6.5% and 6.6% of Hispanic patients with finerenone and placebo, respectively (HR, 0.94; 95% CI, 0.67-1.33). The risk reduction was consistent with that observed in non-Hispanic patients (HR, 0.75; 95% CI, 0.64-0.87; Pinteraction= 0.22). Finerenone reduced UACR by 32% at month 4 in both Hispanic and non-Hispanic patients versus placebo (P < 0.001 for both patient groups). The safety profile of finerenone and incidence of hyperkalemia was similar between Hispanic and non-Hispanic patient groups.

Limitations

Small sample size, short follow-up time, and lower treatment adherence in the Hispanic population.

Conclusions

Overall, the efficacy and safety of finerenone were similar in Hispanic and non-Hispanic patients with CKD and type 2 diabetes.

Funding

Bayer AG.

Trial Registration

ClinicalTrials.gov identifier: NCT02540993, NCT02545049.

Plain-Language Summary

Chronic kidney disease (CKD) in patients with type 2 diabetes occurs more frequently in Hispanic patients than in non-Hispanic patients, with a more rapid progression to kidney failure. Treatment with finerenone reduces the risk of having a kidney or heart event (such as starting dialysis or having a heart attack) in patients with CKD and type 2 diabetes. Because clinical trials that investigate treatments for CKD and type 2 diabetes have not included enough Hispanic patients, the benefits of treatments particularly for Hispanic patients are frequently unknown. This study explores the benefits of finerenone in Hispanic patients. Overall, the study shows that finerenone can provide kidney and heart benefits in Hispanic patients with CKD and type 2 diabetes, as it does in non-Hispanic patients.

Heart Failure-Type Symptom Score Trajectories in CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Quality of life in chronic kidney disease (CKD) is impaired by a large burden of symptoms including some that overlap with the symptoms of heart failure (HF). We studied a group of individuals with CKD to understand the patterns and trajectories of HF-type symptoms in this setting.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,044 participants in the Chronic Renal Insufficiency Cohort (CRIC) without prior diagnosis of HF.

PREDICTORS

Sociodemographics, medical history, medications, vital signs, laboratory values, echocardiographic and electrocardiographic parameters.

OUTCOME

Trajectory over 5.5 years of a HF-type symptom score (modified Kansas City Cardiomyopathy Questionnaire [KCCQ] Overall Summary Score with a range of 0-100 where<75 reflects clinically significant symptoms).

ANALYTICAL APPROACH

Latent class mixed models were used to model trajectories. Multinomial logistic regression was used to model relationships of predictors with trajectory group membership.

RESULTS

Five trajectories of KCCQ score were identified in the cohort of 3,044 adults, 45% of whom were female, and whose median age was 61 years. Group 1 (41.7%) had a stable high score (minimal symptoms, average score of 96); groups 2 (35.6%) and 3 (15.6%) had stable but lower scores (mild symptoms [average of 81] and clinically significant symptoms [average of 52], respectively). Group 4 (4.9%) had a substantial worsening in symptoms over time (mean 31-point decline), and group 5 (2.2%) had a substantial improvement (mean 33-point increase) in KCCQ score. A majority of group 1 was male, without diabetes or obesity, and this group had higher baseline kidney function. A majority of groups 2 and 3 had diabetes and obesity. A majority of group 4 was male and had substantial proteinuria. Group 5 had the highest proportion of baseline cardiovascular disease (CVD).

LIMITATIONS

No validation cohort available, CKD management changes in recent years may alter trajectories, and latent class models depend on the missing at random assumption.

CONCLUSIONS

Distinct HF-type symptom burden trajectories were identified in the setting of CKD, corresponding to different baseline characteristics. These results highlight the diversity of HF-type symptom experiences in individuals with CKD.

A prediction model of CKD progression among individuals with type 2 diabetes in the United States

BACKGROUND

CKD progression among individuals with T2D is associated with poor health outcomes and high healthcare costs, which have not been fully studied. This study aimed to predict CKD progression among individuals with diabetes.

METHOD

Using ACCORD trial data, a time-varying Cox model was developed to predict the risk of CKD progression among patients with CKD and T2D. CKD progression was defined as a 50 % decline, or 25 mL/min/1.73 m² decline in eGFR from baseline, doubling of the serum creatinine, or onset of ESKD. A list of candidate variables included demographic characteristics, physical exam results, laboratory results, medical history, drug use, and healthcare utilization. A stepwise algorithm was used for variable selection. Model performance was evaluated by Brier score and C-statistics. Confidence intervals (CI) were calculated using a bootstrap method. Decomposition analysis was conducted to assess the predictor contribution. Generalizability was assessed on patient-level data of the Harmony Outcome trial and CRIC study.

RESULTS

A total of 6982 diabetes patients with CKD were used for model development, with a median follow-up of 4 years and 3346 events. The predictors for CKD progression included female sex, age at T2D diagnosis, smoking status, SBP, DBP, HR, HbA1c, alanine aminotransferase (ALT), eGFR, UACR, retinopathy event, hospitalization. The model demonstrated good discrimination (C-statistics 0.745 [95 % CI 0.723-0.763]) and calibration (Brier Score 0.0923 [95 % CI 0.0873-0.0965]) performance in the ACCORD data. The most contributing predictors for CKD progression were eGFR, HbA1c, and SBP. The model demonstrated acceptable discrimination and calibration performance in the two external data.

CONCLUSION

For high-risk patients with both diabetes and CKD, the tool as a dynamic risk prediction of CKD progression may help develop novel strategies to lower the risk of CKD progression.

CKD-Associated Cardiovascular Mortality in the United States: Temporal Trends From 1999 to 2020

Rationale & Objective

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular (CV) mortality, but there are limited data on temporal trends disaggregated by sex, race, and urban/rural status in this population.

Study Design

Retrospective observational study.

Setting & Participants

The Centers for Disease Control and Prevention Wide-Ranging, Online Data for Epidemiologic Research database.

Exposure & Predictors

Patients with CKD and end-stage kidney disease (ESKD) stratified according to key demographic groups.

Outcomes

Etiologies of CKD- and ESKD-associated mortality between 1999 and 2000.

Analytical Approach

Presentation of age-adjusted mortality rates (per 100,000 people) characterized by CV categories, ethnicity, sex (male or female), age categories, state, and urban/rural status.

Results

Between 1999 and 2020, we identified 1,938,505 death certificates with CKD (and ESKD) as an associated cause of mortality. Of all CKD-associated mortality, the most common etiology was CV, with 31.2% of cases. Between 1999 and 2020, CKD-related age-adjusted mortality increased by 50.2%, which was attributed to an 86.6% increase in non-CV mortality but a 7.1% decrease in CV mortality. Black patients had a higher rate of CV mortality throughout the study period, although Black patients experienced a 38.6% reduction in mortality whereas White patients saw a 2.7% increase. Hispanic patients experienced a greater reduction in CV mortality over the study period (40% reduction) compared to non-Hispanic patients (3.6% reduction). CV mortality was higher in urban areas in 1999 but in rural areas in 2020.

Limitations

Reliance on accurate characterization of causes of mortality in a large dataset.

Conclusions

Among patients with CKD-related mortality in the United States between 1999 and 2020, there was an increase in all-cause mortality though a small decrease in CV-related mortality. Overall, temporal decreases in CV mortality were more prominent in Hispanic versus non-Hispanic patients and Black patients versus White patients.

Examining post-donation outcomes in Hispanic/Latinx living kidney donors in the United States: A systematic review

We conducted a systematic review to assess outcomes in Hispanic donors and explore how Hispanic ethnicity was characterized. We searched PubMed, EMBASE, and Scopus through October 2021. Two reviewers independently screened study titles, abstracts, and full texts; they also qualitatively synthesized results and independently assessed quality of included studies. Eighteen studies met our inclusion criteria. Study sample sizes ranged from 4007 to 143,750 donors and mean age ranged from 37 to 54 years. Maximum follow-up time of studies varied from a perioperative donor nephrectomy period to 30 years post-donation. Hispanic donors ranged between 6% and 21% of the donor populations across studies. Most studies reported Hispanic ethnicity under race or a combined race and ethnicity category. Compared to non-Hispanic White donors, Hispanic donors were not at increased risk for post-donation mortality, end-stage kidney disease, cardiovascular disease, non-pregnancy-related hospitalizations, or overall perioperative surgical complications. Compared to non-Hispanic White donors, most studies showed Hispanic donors were at higher risk for diabetes mellitus following nephrectomy; however, mixed findings were seen regarding the risk for post-donation chronic kidney disease and hypertension. Future studies should evaluate cultural, socioeconomic, and geographic differences within the heterogeneous Hispanic donor population, which may further explain variation in health outcomes.

Association of elevated serum aminotransferase levels with chronic kidney disease measures: hispanic community health study/study of latinos

Background

Previous studies have shown an association between non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD), but it is unclear whether the association is independent of metabolic syndrome.

Methods

Data from 13,006 participants aged 18 to 74 years in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) without viral hepatitis, excessive alcohol consumption, or high transferrin saturation levels were analyzed. Suspected NAFLD was defined as presence of sex-specific elevations in serum aminotransferase levels (aspartate aminotransferase (AST) > 37 U/L or alanine aminotransferase (ALT) > 40 U/L for men and AST or ALT > 31 U/L for women). Logistic regression was used to examine cross-sectional associations of elevated serum aminotransferase levels with low estimated glomerular filtration rate (eGFR < 60 ml/min/1.73 m² based on cystatin C), and with high urinary albumin-to-creatinine ratio (UACR) (> 17 mg/g in men and > 25 mg/ g in women) in separate models adjusting for demographic characteristics and metabolic syndrome.

Results

Mean (SD) age was 41 (0.27) years, and 45 % were male. Elevated serum aminotransferase levels were noted in 18.8 % of the population and were associated with greater odds of high UACR (OR = 1.31; 95 % CI = 1.10, 1.56) after adjusting for demographic characteristics; this association became non-significant after adjustment for metabolic syndrome (OR = 1.11, 95 % CI = 0.92, 1.33). In contrast, elevated serum aminotransferase levels were not associated with low eGFR (odds ratio (OR) = 0.73; 95 % confidence interval (CI) = 0.45, 1.18) after adjusting for covariates.

Conclusions

In this sample of diverse U.S. Hispanic Latino adults, elevated serum aminotransferase levels were not independently associated with measures of CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02483-y.

Positive effect of home hemodialysis in a pregnant woman with chronic kidney failure during the COVID-19 pandemic: A case report

This report discusses the case of a 25-year-old pregnant woman from an underserved community, with two previous failed kidney transplants and a previous miscarriage. The patient required a progressive increase to 30 h a week of in-hospital hemodialysis during the COVID-19 pandemic lockdown. She delivered her baby while transitioning to home hemodialysis. Women with end-stage kidney disease who require hemodialysis and wish to become pregnant or who are pregnant have options to allow for a safe and healthy delivery. This can be achieved with vigorous hemodialysis, even at home.

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Women with end-stage kidney disease who require hemodialysis and attempting to become pregnant have options to allow for a safe and healthy delivery.

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A safe and healthy delivery can be achieved with vigorous hemodialysis, even at home.

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It may be possible for patients to transition to home hemodialysis from in-center hemodialysis.

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New types of healthcare barriers arose during the COVID-19 pandemic.

Perspectives on Kidney Disease Education and Recommendations for Improvement Among Latinx Patients Receiving Emergency-Only Hemodialysis

IMPORTANCE

In most states, undocumented Latinx immigrants with kidney failure receive dialysis in acute care settings on an emergency-only basis. How much kidney disease education Latinx immigrants receive and how to improve kidney disease education and outreach among Latinx populations are unknown.

OBJECTIVE

To understand the kidney disease educational gaps of Latinx individuals who need but lack access to scheduled outpatient dialysis.

DESIGN, SETTING, AND PARTICIPANTS

This qualitative study used semistructured interviews in a Texas hospital system from March 2020 to January 2021 with 15 individuals who received emergency-only dialysis when they were first diagnosed with kidney failure. Demographic information was collected, and a thematic analysis was performed using the constant comparative method on interviews after they were audio-recorded, translated, and transcribed verbatim. Data analysis was performed from April 2020 to February 2021.

MAIN OUTCOMES AND MEASURES

Subthemes and themes from semistructured interviews.

RESULTS

All 15 persons interviewed (9 male individuals [60%]; mean [SD] age, 51 [17] years) identified as Hispanic, 11 (73%) were born in Mexico, and none reported knowing about their kidney disease more than 6 months before starting dialysis. The themes identified were (1) lack of kidney disease awareness, (2) education provided was incomplete and poor quality, (3) lack of culturally concordant communication and care, (4) elements that Latinx patients receiving emergency-only dialysis want in their education, (5) facilitators of patient activation and coping, and (6) Latinx patient recommendations to improve community outreach.

CONCLUSIONS AND RELEVANCE

Latinx adults receiving emergency-only dialysis are usually unaware of their kidney disease until shortly before or after they start dialysis, and the education they receive is poor quality and often not culturally tailored. Participants made feasible recommendations on how to improve education and outreach among Latinx communities.

Periodontal Disease and Incident CKD in US Hispanics/Latinos: The Hispanic Community Health Study/Study of Latinos

Rationale & Objective

Recent studies suggest that periodontal disease may be associated with incident chronic kidney disease (CKD). However, studies have focused on older populations, and US Hispanics/Latinos were not well represented.

Study Design

Observational cohort.

Setting & Participants

We analyzed data from the Hispanic Community Health Study/Study of Latinos who completed a baseline visit with a periodontal examination and a follow-up visit, and did not have CKD at baseline.

Predictors

Predictors included ≥30% of sites with clinical attachment loss ≥3 mm, ≥30% of sites with probing depth ≥4 mm, percentage of sites with bleeding on probing, and absence of functional dentition (<21 permanent teeth present).

Outcomes

Outcomes were incident low estimated glomerular filtration rate (eGFR) (eGFR <60 mL/min/1.73 m² and decline in eGFR ≥1 mL/min/year); incident albuminuria (urine albumin:creatinine ratio [ACR] ≥30 mg/g); and change in eGFR and ACR.

Analytic Approach

Poisson and linear regression.

Results

For the sample (n = 7.732), baseline mean age was 41.5 years, 45.2% were male, 11.7% had ≥30% of sites with clinical attachment loss ≥3 mm, 5.1% had ≥30% of sites with probing depth ≥4 mm, 30.7% had ≥50% of sites with bleeding on probing, and 16.2% had absent functional dentition. During a median follow-up of 5.9 years, 149 patients developed low eGFR and 415 patients developed albuminuria. On multivariable analysis, presence versus absence of ≥30% of sites with probing depth ≥4 mm and absence of functional dentition were each associated with increased risk for incident low eGFR (incident density ratio, 2.31; 95% CI, 1.14-4.65 and 1.65, 95% CI, 1.01-2.70, respectively). None of the other predictors were associated with outcomes.

Limitations

Only a single kidney function follow-up measure.

Conclusions

In this cohort of US Hispanics/Latinos, we found that select measures of periodontal disease were associated with incident low eGFR. Future work is needed to assess whether the treatment of periodontal disease may prevent CKD.

Risk Factors for CKD Progression: Overview of Findings from the CRIC Study

The Chronic Renal Insufficiency Cohort (CRIC) Study is an ongoing, multicenter, longitudinal study of nearly 5500 adults with CKD in the United States. Over the past 10 years, the CRIC Study has made significant contributions to the understanding of factors associated with CKD progression. This review summarizes findings from longitudinal studies evaluating risk factors associated with CKD progression in the CRIC Study, grouped into the following six thematic categories: (1) sociodemographic and economic (sex, race/ethnicity, and nephrology care); (2) behavioral (healthy lifestyle, diet, and sleep); (3) genetic (apoL1, genome-wide association study, and renin-angiotensin-aldosterone system pathway genes); (4) cardiovascular (atrial fibrillation, hypertension, and vascular stiffness); (5) metabolic (fibroblast growth factor 23 and urinary oxalate); and (6) novel factors (AKI and biomarkers of kidney injury). Additionally, we highlight areas where future research is needed, and opportunities for interdisciplinary collaboration.

Sedentary Behavior and Change in Kidney Function: The Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

BACKGROUND

There is accumulating evidence linking prolonged sedentary time to adverse health outcomes. The effect of sedentary behavior on kidney function has not been evaluated in US Hispanics/Latinos, a population disproportionately affected by CKD.

METHODS

We evaluated the association between accelerometer-measured (1 week) sedentary time at baseline and kidney function among 7134 adults without CKD at entry in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), who completed a baseline visit with accelerometry (2008-2011) and a follow-up visit (2014-2017). Outcomes included: (1) change in kidney function (eGFR and urine albumin-to-creatinine ratio, ACR), (2) incident low eGFR (eGFR <60 ml/min per 1.73 m2 and eGFR decline ≥1 ml/min per year), and (3) incident albuminuria (ACR ≥17 mg/g in men or ≥25 mg/g in women). Linear regression using survey procedures was used to evaluate change in kidney function (eGFR and ACR), and Poisson regression with robust variance was used to evaluate incident low eGFR and albuminuria.

RESULTS

The median sedentary time was 12 hours/d. Over a median follow-up of 6.1 years, the mean relative change in eGFR was -0.50% per year, and there were 167 incident low eGFR events. On multivariable analysis, each 1 hour increase in sedentary time was associated with a longitudinal decline in eGFR (-0.06% per year, 95% CI, -0.10 to -0.02). There was a significant interaction with sex, and on stratified analyses, higher sedentary time was associated with eGFR decline in women but not men. There was no association between sedentary time and the other outcomes.

CONCLUSIONS

Sedentary time was associated with a small longitudinal decline in eGFR, which could have important implications in a population that experiences a disproportionate burden of CKD but further investigation is needed.

Neighborhood context and kidney disease in Philadelphia

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

Association of Diet Quality Indices with Longitudinal Changes in Kidney Function in U.S. Hispanics/Latinos: Findings from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Background

Recent studies suggest an association between diet quality and incident CKD. However, Hispanics/Latinos were under-represented in these studies. We examined the relationship of diet quality with change in kidney function in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Methods

Individuals who participated in HCHS/SOL visits 1 (2008-2011) and 2 (2014-2017) were analyzed (n=9921). We used Alternate Healthy Eating Index 2010 (AHEI-2010), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean Diet (MeDS) scores as measures of dietary quality. Scores were calculated from two 24-hour dietary recalls administered at visit 1 and categorized into quartiles of each dietary score (higher quartiles correspond to a healthier diet). Kidney function was assessed at both visits using eGFR and urine albumin-creatinine ratio (UACR). Annualized change was computed as the difference in eGFR or UACR between visits divided by follow-up time in years. Weighted linear-regression models were used to examine the association between quartiles of each dietary quality index and annualized change in eGFR and UACR, adjusted for potential confounders.

Results

At visit 1, the mean (SD) age of participants was 41 (0.28) years, and 56% were female. The baseline mean eGFR was 107.1 ml/min per 1.73 m², and baseline median UACR was 6.1 mg/g. On average, eGFR declined by 0.65 ml/min per 1.73 m² per year, and UACR increased by 0.79 mg/g per year over a 6-year period. Lower AHEI-2010 quartiles were associated with eGFR decline in a dose-response manner (P trend=0.02). Higher AHEI-2010 quartiles showed a trend toward lower annualized change in UACR, but the result did not reach significance. Neither MeDS nor DASH scores were associated with eGFR decline or change in UACR.

Conclusions

Unhealthy diet, assessed at baseline by AHEI-2010, was associated with kidney-function decline over 6 years. Improving the quality of foods and nutrients according to the AHEI-2010 may help maintain kidney function in the Hispanic/Latino community.

Slope of Kidney Function and Its Association with Longitudinal Mortality and Cardiovascular Disease among Individuals with CKD

BACKGROUND

Slopes of eGFR have been associated with increased risks of death and cardiovascular events in a U-shaped fashion. Poor outcomes in individuals with rising eGFR are potentially attributable to sarcopenia, hemodilution, and other indicators of clinical deterioration.

METHODS

To investigate the association between eGFR slopes and risks of death or cardiovascular events, accounting for multiple confounders, we studied 2738 individuals with moderate to severe CKD participating in the multicenter Chronic Renal Insufficiency Cohort (CRIC) Study. We used linear, mixed-effects models to estimate slopes with up to four annual eGFR assessments, and Cox proportional hazards models to investigate the association between slopes and the risks of death and cardiovascular events.

RESULTS

Slopes of eGFR had a bell-shaped distribution (mean [SD], -1.5 [-2] ml/min per 1.73 m² per year). Declines of eGFR that were steeper than the average decline associated with progressively increasing risks of death (hazard ratio [HR], 1.23; 95% confidence interval [95% CI], 1.09 to 1.39; for a slope 1 SD below the average) and cardiovascular events (HR, 1.19; 95% CI, 1.03 to 1.38). Rises of eGFR or declines lower than the average decline were not associated with the risk of death or cardiovascular events.

CONCLUSIONS

In a cohort of individuals with moderate to severe CKD, we observed steep declines of eGFR were associated with progressively increasing risks of death and cardiovascular events; however, we found no increased risks associated with eGFR improvement. These findings support the potential value of eGFR slopes in clinical assessment of adults with CKD.

Ethnic minority disparities in progression and mortality of pre-dialysis chronic kidney disease: a systematic scoping review

Background

There are a growing number of studies on ethnic differences in progression and mortality for pre-dialysis chronic kidney disease (CKD), but this literature has yet to be synthesised, particularly for studies on mortality.

Methods

This scoping review synthesized existing literature on ethnic differences in progression and mortality for adults with pre-dialysis CKD, explored factors contributing to these differences, and identified gaps in the literature. A comprehensive search strategy using search terms for ethnicity and CKD was taken to identify potentially relevant studies. Nine databases were searched from 1992 to June 2017, with an updated search in February 2020.

Results

8059 articles were identified and screened. Fifty-five studies (2 systematic review, 7 non-systematic reviews, and 46 individual studies) were included in this review. Most were US studies and compared African-American/Afro-Caribbean and Caucasian populations, and fewer studies assessed outcomes for Hispanics and Asians. Most studies reported higher risk of CKD progression in Afro-Caribbean/African-Americans, Hispanics, and Asians, lower risk of mortality for Asians, and mixed findings on risk of mortality for Afro-Caribbean/African-Americans and Hispanics, compared to Caucasians. Biological factors such as hypertension, diabetes, and cardiovascular disease contributed to increased risk of progression for ethnic minorities but did not increase risk of mortality in these groups.

Conclusions

Higher rates of renal replacement therapy among ethnic minorities may be partly due to increased risk of progression and reduced mortality in these groups. The review identifies gaps in the literature and highlights a need for a more structured approach by researchers that would allow higher confidence in single studies and better harmonization of data across studies to advance our understanding of CKD progression and mortality.

Metabolomic Markers of Kidney Function Decline in Patients With Diabetes: Evidence From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Biomarkers that provide reliable evidence of future diabetic kidney disease (DKD) are needed to improve disease management. In a cross-sectional study, we previously identified 13 urine metabolites that had levels reduced in DKD compared with healthy controls. We evaluated associations of these 13 metabolites with future DKD progression.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

1,001 Chronic Renal Insufficiency Cohort (CRIC) participants with diabetes with estimated glomerular filtration rates (eGFRs) between 20 and 70mL/min/1.73m² were followed up prospectively for a median of 8 (range, 2-10) years.

PREDICTORS

13 urine metabolites, age, race, sex, smoked more than 100 cigarettes in lifetime, body mass index, hemoglobin A_1c level, blood pressure, urinary albumin, and eGFR.

OUTCOMES

Annual eGFR slope and time to incident kidney failure with replacement therapy (KFRT; ie, initiation of dialysis or receipt of transplant).

ANALYTICAL APPROACH

Several clinical metabolite models were developed for eGFR slope as the outcome using stepwise selection and penalized regression, and further tested on the time-to-KFRT outcome. A best cross-validated (final) prognostic model was selected based on high prediction accuracy for eGFR slope and high concordance statistic for incident KFRT.

RESULTS

During follow-up, mean eGFR slope was-1.83±1.92 (SD) mL/min/1.73m² per year; 359 (36%) participants experienced KFRT. Median time to KFRT was 7.45 years from the time of entry to the CRIC Study. In our final model, after adjusting for clinical variables, levels of metabolites 3-hydroxyisobutyrate (3-HIBA) and 3-methylcrotonyglycine had a significant negative association with eGFR slope, whereas citric and aconitic acid were positively associated. Further, 3-HIBA and aconitic acid levels were associated with higher and lower risk for KFRT, respectively (HRs of 2.34 [95% CI, 1.51-3.62] and 0.70 [95% CI, 0.51-0.95]).

LIMITATIONS

Subgroups for whom metabolite signatures may not be optimal, nontargeted metabolomics by flow-injection analysis, and 2-stage modeling approaches.

CONCLUSIONS

Urine metabolites may offer insights into DKD progression. If replicated in future studies, aconitic acid and 3-HIBA could identify individuals with diabetes at high risk for GFR decline, potentially leading to improved clinical care and targeted therapies.

Prevalence, Awareness, and Treatment of Hypertension in Hispanics/Latinos With CKD in the Hispanic Community Health Study/Study of Latinos

Rationale & Objective

Lower rates of hypertension awareness, treatment, and control have been observed in Hispanics/Latinos compared with non-Hispanic whites. These factors have not been studied in Hispanics/Latinos with chronic kidney disease (CKD). We sought to describe the prevalence, awareness, treatment, and control of hypertension in Hispanic/Latino adults with CKD.

Study Design

Cross-sectional cohort.

Setting & Participants

US.Hispanics/Latinos aged 18 to 74 years enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) with CKD. Comparisons were made with the National Health and Nutrition Examination Survey (NHANES) 2007 to 2010.

Exposure

CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m² or urinry albumin-creatinine ratio ≥ 30 mg/g creatinine.

Outcomes

Hypertension was defined as systolic blood pressure (BP) ≥ 140 or diastolic BP ≥ 90 mm Hg or use of antihypertensives. For hypertension control, 2 thresholds were examined: <140/90 and <130/80 mm Hg.

Results

The prevalence of hypertension was 51.5%; among those with hypertension, hypertension awareness and treatment were present in 78.1% and 70.4%, respectively. A low prevalence of BP control was observed (32.6% with BP < 140/90 mm Hg; 17.9% with BP < 130/80 mm Hg). Health insurance coverage was associated with higher odds of BP < 140/90 mm Hg (OR, 1.98; 95% CI, 1.15-3.43). Compared with non-Hispanic whites with CKD in NHANES, HCHS/SOL participants with CKD had a lower prevalence of hypertension but a lower rate of BP control (32.6% vs 48.6% for BP < 140/90 mm Hg).

Limitations

Use of a single measurement of creatinine, cystatin C, and urinary albumin excretion to define CKD. Single-visit measurement of BP.

Conclusions

Hispanics/Latinos with CKD residing in the United States have very low rates of BP control. The association of health insurance coverage with hypertension control suggests that improved access to health care may improve outcomes for this growing population.

Specific impact of past and new major cardiovascular events on acute kidney injury and end-stage renal disease risks in diabetes: a dynamic view

BACKGROUND

Interconnections between major cardiovascular events (MCVEs) and renal events are recognized in diabetes, however, the specific impact of atrial fibrillation (AF), heart failure (HF) and acute coronary syndrome (ACS) on the risk of end-stage renal disease (ESRD) on top of established renal risk factors is unclear in type 2 diabetes mellitus.

METHODS

We conducted a retrospective study in 861 consecutive patients followed in a nephrology setting during the 2000-13 period.

RESULTS

The mean age was 70 ± 10 years, 65.1% were men and the estimated glomerular filtration rate (eGFR) was 42.4 ± 21.0 mL/min/1.73 m2. During follow-up (median 59 months), 194 patients reached ESRD. A history of AF, HF or ACS was associated with an increased risk of reduced baseline eGFR. In turn, reduced baseline eGFR resulted in a greater risk of new MCVE (especially HF) during follow-up. Finally, all new MCVEs were risk factors for subsequent acute kidney injury (AKI) {HF: hazard ratio [HR] 8.99 [95% confidence interval (CI) 7.06-11.4]; AF: HR 5.42 (3.91-7.52); ACS: HR 8.82 (6.24-12.5); all P < 0.0001} and ESRD [HF: HR 5.52 (95% CI 4.01-7.60), P < 0.0001; AF: HR 3.48 (2.30-5.21), P < 0.0001; ACS: HR 2.31 (1.43-3.73), P = 0.0006]. The AF- and HF-associated risks of ESRD were significant after adjustments on all renal risks of ESRD (gender, blood pressure, eGFR, albuminuria, renin-angiotensin blockers, retinopathy and AKI), but the association was less strong for ACS. Importantly, no association was noted between other major events such as stroke or infections and the risk of ESRD.

CONCLUSIONS

Past and new cardiovascular events (more HF and AF than ACS) have a strong, independent impact on the development of ESRD above and beyond established risk factors in diabetes.

Renal Function Decline in Latinos With Type 2 Diabetes

Introduction

Diabetic nephropathy remains a highly prevalent microvascular complication in individuals with type 2 diabetes mellitus (T2DM). Hispanic individuals are at increased risk of metabolic and cardiovascular complications compared with non-Hispanic white individuals. We described the long-term kidney outcomes using a culturally based approach to diabetes management in Hispanic patients implemented by the Joslin Diabetes Center’s Latino Diabetes Initiative.

Methods

Our retrospective study included 594 Hispanic patients evaluated at the Joslin Diabetes Center from July 2002 to July 2015. Demographic and clinical data were collected from the outpatient visits.

Results

Uncontrolled high blood pressure (hazard ratio [HR]: 1.72; 95% confidence interval [CI]:1.18–2.51; P = 0.005), overweight (HR: 2.68; 95% CI: 1.13–6.38; P = 0.026), and longstanding T2DM duration (HR: 1.11; 95% CI: 1.08–1.14; P < 0.0001) at baseline were significantly associated with increased risk of chronic kidney disease (CKD). Although poor glycemic control (HR: 1.18; 95% CI: 1.099–1.258; P < 0.0001), systolic blood pressure (SBP) >140 (HR: 1.01; 95% CI: 1.006–1.02; P = 0.0002), and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use (HR: 1.53; 95% CI: 1.03–2.29; P = 0.04) were significantly associated with increased CKD incidence during follow-up. Interestingly, statin use was associated with lower CKD incidence during the follow-up (HR: 0.52; 95% CI: 0.42–0.65; P < 0.0001). The annual rate of renal function decline in our cohort was estimated to be –1.39 ml/min per 1.73 m².

Conclusion

Renal function decline in Latinos is associated with expected but modifiable variables, such as uncontrolled diabetes, uncontrolled hypertension, and being overweight. However, the annual rate of renal function decline in our cohort was estimated to be comparatively higher than previous reports in Hispanic individuals without T2DM, and the general US population with T2DM, but lower than expected for this high-risk group. We highlight the importance of a culturally based patient-centered therapeutic approach to improve long-term outcomes in Hispanic patients at high risk of CKD.

Racial disparities in end-stage renal disease in a high-risk population: the Southern Community Cohort Study

INTRODUCTION

The Southern Community Cohort Study is a prospective study of low socioeconomic status (SES) blacks and whites from the southeastern US, where the burden of end-stage renal disease (ESRD) and its risk factors are high. We tested whether the 2.4-fold elevated risk of ESRD we previously observed in blacks compared to whites was explained by differences in baseline kidney function.

METHODS

We conducted a case-cohort study of incident ESRD cases (n = 737) with stored blood and a probability sampled subcohort (n = 4238) and calculated estimated glomerular filtration rate (eGFR) from serum creatinine. 86% of participants were enrolled from community health centers in medically underserved areas and 14% from the general population in 12 states in the southeastern United States. Incident ESRD after entry into the cohort was ascertained by linkage of the cohort with the US Renal Data System (USRDS).

RESULTS

Median (25th, 75th percentile) eGFR at baseline was 63.3 (36.0, 98.2) ml/min/1.73m2 for ESRD cases and 103.2 (86.0, 117.9) for subcohort. Black ESRD cases had higher median (25th, 75th) eGFR [63.3 (35.9, 95.9)] compared to whites [59.1 (39.4, 99.2)]. In multivariable Cox models accounting for sampling weights, baseline eGFR was a strong predictor of ESRD risk, and an interaction with race was detected (P = 0.029). The higher ESRD risk among blacks relative to whites persisted (hazard ratio: 2.58; 95% confidence interval: 1.65, 4.03) after adjustment for eGFR.

CONCLUSION

In this predominantly lower SES cohort, the racial disparity in ESRD risk is not explained by differences in baseline kidney function.

Delayed Initiation of Hemodialysis in Pregnant Women with Chronic Kidney Disease: Logistical Problems Impact Clinical Outcomes. An Experience from an Emerging Country

BACKGROUND

Chronic kidney disease (CKD) is associated with reduction of fertility and increased complications during pregnancy. The aim of this work is to analyze the clinical outcomes and risk factors in pregnant women who needed to start dialysis with different schedules in a public hospital in Mexico City, with particular attention on the interference of social and cultural elements as well as resource limitations.

MATERIAL AND METHODS

CKD women who needed dialysis in pregnancy over the period 2002⁻2014 and had with complete demographic and outcome data were included in this retrospective study. Clinical background, renal function during pregnancy, dialysis schedule, and clinical outcomes were reviewed.

RESULTS

Forty pregnancies in women with CKD who needed dialysis in pregnancy (39 singleton and one twin pregnancy) were studied: All patients were treated with hemodialysis. Thirty-nine patients had CKD stages 4 or 5 at referral; only one patient was of stage 3b. Dialysis was considered as indicated in the presence of fluid overload, unresponsive hypertension in the setting of advanced CKD, or when blood urea nitrogen values were increased to around 50 mg/dL. However, the initiation of dialysis was often delayed by days or weeks. The main reason for delaying the initiation of dialysis was patient (and family) refusal to start treatment. All patients were treated with thrice weekly dialysis, in 3⁻5 hour sessions, with a target urea of <100 mg/dL. The number of hours on dialysis did not impact pregnancy outcomes. Ten pregnancies ended in miscarriages (8 spontaneous), 29 in pre-term delivery, and 1 in term delivery. Fifteen women were diagnosed with preeclampsia, one with eclampsia, and one with HELLP (hemolysis, elevated liver enzymes, low platelets,) syndrome. Twenty-four of the neonates survived (77.4% of live births); six singletons and one twin died as a consequence of prematurity. Two neonates displayed malformations: cleft palate with ear anomalies and duodenal atresia.

CONCLUSIONS

CKD requiring hemodialysis in pregnancy is associated with a high frequency of complications; in the setting of delayed start and of thrice-weekly hemodialysis, dialysis schedules do not appear to influence outcomes.

Racial Disparities in Nephrology Consultation and Disease Progression among Veterans with CKD: An Observational Cohort Study

BACKGROUND

Incident rates of ESRD are much higher among black and Hispanic patients than white patients. Access to nephrology care before progression to ESRD is associated with better clinical outcomes among patients with CKD. However, it is unknown whether black or Hispanic patients with CKD experience lower pre-ESRD nephrology consultation rates compared with their white counterparts, or whether such a disparity contributes to worse outcomes among minorities.

METHODS

We assembled a retrospective cohort of patients with CKD who received care through the Veterans Health Administration from 2003 to 2015, focusing on individuals with incident CKD stage 4 who had an initial eGFR≥60 ml/min per 1.73 m² followed by two consecutive eGFRs<30 ml/min per 1.73 m². We repeated analyses among individuals with incident CKD stage 3. Outcomes included nephrology provider referral, nephrology provider visit, progression to CKD stage 5, and mortality.

RESULTS

We identified 56,767 veterans with CKD stage 4 and 640,704 with CKD stage 3. In both cohorts, rates of nephrology referral and visits were significantly higher among black and Hispanic veterans than among non-Hispanic white veterans. Despite this, both black and Hispanic patients experienced faster progression to CKD stage 5 compared with white patients. Black patients with CKD stage 4 experienced slightly lower mortality than white patients, whereas black patients with CKD stage 3 had a small increased risk of death.

CONCLUSIONS

Black or Hispanic veterans with CKD are more likely than white patients to see a nephrologist, yet are also more likely to suffer disease progression. Biologic and environmental factors may play a bigger role than nephrology consultation in driving racial disparities in CKD progression.

Time-Centered Approach to Understanding Risk Factors for the Progression of CKD

BACKGROUND AND OBJECTIVES

Traditional approaches to modeling risk of CKD progression do not provide estimates of the time it takes for disease progression to occur, which could be useful in guiding therapeutic interactions between patients and providers. Our objective was to estimate median time spent in each of CKD stages 3a-5 and how the time differs according to risk factors associated with progression of disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included 3682 participants of the Chronic Renal Insufficiency Cohort in mixed models to estimate person-specific trajectories of function, and used these trajectories to estimate time spent in each CKD stage.

RESULTS

During 9.5 years of median follow-up, participants spent longer in earlier rather than later CKD stages, ranging from a median of 7.9 years (interquartile range, 2.3 to >12 years) in stage 3a to 0.8 years (interquartile range, 0.3-1.6) in stage 5. Known risk factors for CKD progression were also associated with larger differences in time until progression to the next CKD stage in earlier versus later stages of disease. For example, compared with systolic BP <140 mm Hg, systolic BP ≥140 mm Hg was associated with 6.1 years shorter time (95% confidence interval [95% CI], 4.5 to 7.5) spent in stage 3a, 3.3 years shorter time (95% CI, 2.7 to 4.0) in stage 3b, but only 2.4 months shorter time (95% CI, 0.8 to 3.6) in stage 5. Compared with those with proteinuria <1 g/g, proteinuria ≥1 g/g was associated with 8 years shorter time spent (95% CI, 6.8 to 9.6) in stage 3a, 5.6 years shorter time (95% CI, 5.0 to 6.4) in stage 3b, but only 6 months shorter time (95% CI, 3.8 to 8) in stage 5.

CONCLUSIONS

There are marked variations in the time spent in the different stages of CKD, according to risk factors and stage of disease.

CKD and ESRD in US Hispanics

Hispanics are the largest racial/ethnic minority group in the United States, and they experience a substantial burden of kidney disease. Although the prevalence of chronic kidney disease (CKD) is similar or slightly lower in Hispanics than non-Hispanic whites, the age- and sex-adjusted prevalence rate of end-stage renal disease is almost 50% higher in Hispanics compared with non-Hispanic whites. This has been attributed in part to faster CKD progression among Hispanics. Furthermore, Hispanic ethnicity has been associated with a greater prevalence of cardiovascular disease risk factors, including obesity and diabetes, as well as CKD-related complications. Despite their less favorable socioeconomic status, which often leads to limited access to quality health care, and their high comorbid condition burden, the risk for mortality among Hispanics appears to be lower than for non-Hispanic whites. This survival paradox has been attributed to a complex interplay between sociocultural and psychosocial factors, as well as other factors. Future research should focus on evaluating the long-term impact of these factors on patient-centered and clinical outcomes. National policies are needed to improve access to and quality of health care among Hispanics with CKD.

Acculturation and chronic kidney disease in the Hispanic community health study/study of Latinos (HCHS/SOL)

Hispanics/Latinos are burdened by chronic kidney disease (CKD). The role of acculturation in this population has not been explored. We studied the association of acculturation with CKD and cardiovascular risk factor control. We performed cross-sectional analyses of 13,164 U.S. Hispanics/Latinos enrolled in the HCHS/SOL Study between 2008 and 2011. Acculturation was measured using the language and ethnic social relations subscales of the Short Acculturation Scale for Hispanics, and proxies of acculturation (language preference, place of birth and duration of residence in U.S.). CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² or urine albumin-to-creatinine ratio ≥ 30 mg/g. On multivariable analyses stratified by age, lower language subscale score was associated with higher odds of CKD among those older than 65 (OR 1.29, 95% CI, 1.03, 1.63). No significant association was found between proxies of acculturation and CKD in this age strata. Among individuals aged 18–44, a lower language subscale score was associated with lower eGFR (β = −0.77 ml/min/1.73 m², 95% CI −1.43, −0.10 per 1 SD increase) and a similar pattern was observed for ethnic social relations. Among those older than 65, lower language subscale score was associated with higher log-albuminuria (β = 0.12, 95% CI 0.03, 0.22). Among individuals with CKD, acculturation measures were not associated with control of cardiovascular risk factors. In conclusion, lower language acculturation was associated with a higher prevalence of CKD in individuals older than 65. These findings suggest that older individuals with lower language acculturation represent a high risk group for CKD.

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Among Hispanics/Latinos, lower language acculturation was associated with a higher prevalence of chronic kidney disease in older individuals.

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Based on our findings, older individuals with lower language acculturation represent a high-risk group for chronic kidney disease.

Relationships of kidney injury molecule-1 with renal function and cardiovascular risk factors in the general population

BACKGROUND

Kidney injury molecule-1 (KIM-1) has been associated with kidney damage in patients with preexisting renal disease. However, little is known about the relationships of KIM-1 with renal function and cardiovascular risk factors in healthy individuals from the general population.

METHODS

Healthy individuals aged 25-41years were enrolled in a population-based study. Main exclusion criteria were a BMI >35kg/m², preexisting kidney disease or established cardiovascular disease. KIM-1 was measured from frozen plasma samples using a high-sensitivity assay. Multivariable linear regression models were constructed to assess the relationships of KIM-1 with renal function and various cardiovascular risk factors.

RESULTS

We included 2060 individuals (47% men, median (interquartile range) age: 37 (31-40) years) in this analysis. Median KIM-1 levels were 82.5 (IQR 59.4-112.7) pg/ml. We found no significant relationship of KIM-1 with creatinine (adjusted β-coefficient (95% confidence interval) 0.0005 (-0.002; 0.003), p=0.61) and cystatin C (-0.02 (-0.21; 0.17), p=0.84). There were significant linear relationships of log-transformed KIM-1 with systolic blood pressure (adjusted β-coefficient (95% confidence interval) 0.07 (0.04; 0.09), p<0.0001), diastolic blood pressure (0.04 (0.02; 0.07), p=0.001), low-density lipoprotein cholesterol (0.09 (0.06; 0.11), p<0.0001), high-density lipoprotein cholesterol (0.07 (0.05; 0.1), p<0.0001), high-sensitivity C-reactive protein (0.05 (0.03; 0.07), p<0.0001), age (0.09 (0.07; 0.11), p<0.0001), BMI (0.04 (0.01; 0.06), p=0.005) and current smoking (0.12 (0.07; 0.17), p<0.0001).

CONCLUSION

Among healthy adults from the general population, plasma levels of KIM-1 were not associated with renal function but were independently related to multiple cardiovascular risk factors.

Role of Nitric Oxide Pathway in Development and Progression of Chronic Kidney Disease in Rats Sensitive and Resistant to its Occurrence in an Experimental Model of 5/6 Nephrectomy

BACKGROUND Understanding the mechanisms conditioning development of chronic kidney disease (CKD) is still a challenge. The aim of this study was to evaluate the activity of the intrarenal nitric oxide (NO) pathway in the context of sensitivity or resistance of different animal strains to the development and degree of renal failure. MATERIAL AND METHODS Two rat strains were used: Wistar (WR) and Sprague-Dawley rats (SDR) in a model of CKD - 5/6 nephrectomy. We assessed parameters of renal failure and expression of nitric oxide synthase (NOS) isoforms in renal cortex and medulla. RESULTS We did not observe renal failure in WR, and CKD developed in SDR with increase of creatinine and urea concentration as well as decrease of diuresis and glomerular filtration. In the renal cortex, baseline expression of NOS2 was higher in WR than in SDR. 5/6 nephrectomy resulted in reduction of NOS2 in both strains and NOS3 in WR. In the renal medulla, baseline NOS2 expression was higher in SDR, and nephrectomy resulted in its decrease only in SDR. Although baseline NOS3 expression was higher in SDR, the NOS3 expression after nephrectomy was higher in WR rats. CONCLUSIONS In model of CKD - 5/6 nephrectomy, SDR proved to be sensitive and WR resistant to development of CKD. The intrarenal activity of the nitric oxide pathway was the factor that differentiated both strains. This mechanism may be responsible for insensitivity of WR to development of renal failure in this model of CKD.

Analytic Considerations for Repeated Measures of eGFR in Cohort Studies of CKD

Repeated measures of various biomarkers provide opportunities for us to enhance understanding of many important clinical aspects of CKD, including patterns of disease progression, rates of kidney function decline under different risk factors, and the degree of heterogeneity in disease manifestations across patients. However, because of unique features, such as correlations across visits and time dependency, these data must be appropriately handled using longitudinal data analysis methods. We provide a general overview of the characteristics of data collected in cohort studies and compare appropriate statistical methods for the analysis of longitudinal exposures and outcomes. We use examples from the Chronic Renal Insufficiency Cohort Study to illustrate these methods. More specifically, we model longitudinal kidney outcomes over annual clinical visits and assess the association with both baseline and longitudinal risk factors.