Impact of Race-Free Glomerular Filtration Rate Estimations on CKD Prevalence in the US Military Health System: A Retrospective Cohort Study.

Rationale & Objective: The 2021 CKD-EPI removes Black race as a factor in calculating the estimated glomerular filtration rate (eGFR). We assessed its effect on CKD prevalence in the demographically-diverse US Military Health System. Study Design: A retrospective calculation of the eGFR from serum creatinine measured over 2016-2019 using both the 2009 and 2021 CKD-EPI equations. Setting & Population: Multicenter health care network with data from 1,502,607 adults in the complete case analysis and from 1,970,433 adults in an imputed race analysis. Predictors: Serum creatinine, age, sex, and race. Outcome: CKD stages 3-5, defined as the last eGFR persistently < 60 mL/min/1.73m2 for ≥90 days. Analytical Approach: The t test and Kruskal-Wallis test were used for continuous variables and Χ2 for categorical data. Results: The population in the complete case analysis had a median age of 40 years and was 18.8% Black race and 35.4% female. With the 2021 equation, the number of Black adults with CKD stages 3-5 increased by 58.1% from 4,147 to 6,556, a change in the crude prevalence from 1.47% to 2.32%. The number of non-Black adults with CKD stages 3-5 decreased by 30.4% from 27,596 to 19,213, a crude prevalence change from 2.26% to 1.58%. Similar results were seen with race imputation. Cumulatively, among adults with CKD stages 3-5 by at least one equation, 45.8% of Black adults were reclassified to more advanced stages of CKD and 44.0% of non-Black adults were reclassified to less severe stages across eGFR thresholds that could change clinical management. Limitations: Potential underestimation of CKD in individuals with only 1 measurement. Conclusions: Adoption of the 2021 CKD-EPI equation in the Military Health System reclassifies many Black adults into new CKD stages 3-5 or into more advanced CKD stages, with the opposite effect on non-Black adults. This may have an effect on CKD treatment and outcomes in ways that are yet unknown.

Until recently, kidney function level was calculated from equations that adjusted the result if the individual was of Black race. Because this may contribute to racial disparities in kidney disease care, a new equation was developed in 2021 that excludes race as a factor. We assessed the possible effects of this equation using data from adults in the US Military Health System from 2016 to 2019. With the new equation, the number of Black adults classified with kidney disease increased while that of non-Black adults decreased. There were similar trends seen in the more severe levels of kidney disease, which could affect decisions in clinical care. These results emphasize the potential positive and negative outcomes to be monitored with the new equation.

Risk Factors Amenable to Primary Prevention of Type 2 Diabetes Among Disaggregated Racial and Ethnic Subgroups in the U.S.

OBJECTIVE: Race and ethnicity data disaggregated into detailed subgroups may reveal pronounced heterogeneity in diabetes risk factors. We therefore used disaggregated data to examine the prevalence of type 2 diabetes risk factors related to lifestyle behaviors and barriers to preventive care among adults in the U.S. RESEARCH DESIGN AND METHODS: We conducted a pooled cross-sectional study of 3,437,640 adults aged ≥18 years in the U.S. without diagnosed diabetes from the Behavioral Risk Factor Surveillance System (2013-2021). For self-reported race and ethnicity, the following categories were included: Hispanic (Cuban, Mexican, Puerto Rican, Other Hispanic), non-Hispanic (NH) American Indian/Alaska Native, NH Asian (Chinese, Filipino, Indian, Japanese, Korean, Vietnamese, Other Asian), NH Black, NH Pacific Islander (Guamanian/Chamorro, Native Hawaiian, Samoan, Other Pacific Islander), NH White, NH Multiracial, NH Other. Risk factors included current smoking, hypertension, overweight or obesity, physical inactivity, being uninsured, not having a primary care doctor, health care cost concerns, and no physical exam in the past 12 months. RESULTS: Prevalence of hypertension, lifestyle factors, and barriers to preventive care showed substantial heterogeneity among both aggregated, self-identified racial and ethnic groups and disaggregated subgroups. For example, the prevalence of overweight or obesity ranged from 50.8% (95% CI 49.1-52.5) among Chinese adults to 79.8% (73.5-84.9) among Samoan adults. Prevalence of being uninsured among Hispanic subgroups ranged from 11.4% (10.9-11.9) among Puerto Rican adults to 33.0% (32.5-33.5) among Mexican adults. CONCLUSIONS: These findings underscore the importance of using disaggregated race and ethnicity data to accurately characterize disparities in type 2 diabetes risk factors and access to care.

Change in testing for blood glucose during the COVID-19 pandemic, United States 2019-2021.

AIM: This study assessed changes in testing for blood glucose in the United States (US) from 2019 to 2021. METHODS: We conducted a serial cross-sectional analysis of the 2019-2021 National Health Interview Survey by including adults aged ≥ 18 years without reported diagnosed diabetes. We estimated the prevalence of testing for blood glucose within 12 months and the difference in the testing prevalence between 2019 and 2021. RESULTS: The study sample included 82,594 respondents without diabetes in 2019--2021, with a mean age between 46.4 and 46.8 years. Overall, the prevalence of testing for blood glucose decreased significantly from 64.2 % (95 % confidence interval [CI] 63.3 %, 65.1 %) in 2019 to 60.0 % (95 % CI 59.1 %, 60.9 %) in 2021. Among adults who met the United States Preventive Services Task Force's 2015 screening recommendation, the prevalence decreased from 73.4 % (95 % CI 72.2 %, 74.6 %) to 69.5 % (95 % CI 68.3 %, 70.6 %). Although decreases in testing were observed in most groups, the extent of the decline differed by subgroups. CONCLUSIONS: Testing for blood glucose decreased in the US during the COVID-19 pandemic. This may have delayed diagnosis and treatment of prediabetes and diabetes, underscoring the importance of continued access to diabetes screening during pandemics.

Trends in all-cause mortality among people with diagnosed diabetes in high-income settings: a multicountry analysis of aggregate data.

BACKGROUND: Population-level trends in mortality among people with diabetes are inadequately described. We aimed to examine the magnitude and trends in excess all-cause mortality in people with diabetes. METHODS: In this retrospective, multicountry analysis, we collected aggregate data from 19 data sources in 16 high-income countries or jurisdictions (in six data sources in Asia, eight in Europe, one from Australia, and four from North America) for the period from Jan 1, 1995, to Dec 31, 2016, (or a subset of this period) on all-cause mortality in people with diagnosed total or type 2 diabetes. We collected data from administrative sources, health insurance records, registries, and a health survey. We estimated excess mortality using the standardised mortality ratio (SMR). FINDINGS: In our dataset, there were approximately 21 million deaths during 0·5 billion person-years of follow-up among people with diagnosed diabetes. 17 of 19 data sources showed decreases in the age-standardised and sex-standardised mortality in people with diabetes, among which the annual percentage change in mortality ranged from -0·5% (95% CI -0·7 to -0·3) in Hungary to -4·2% (-4·3 to -4·1) in Hong Kong. The largest decreases in mortality were observed in east and southeast Asia, with a change of -4·2% (95% CI -4·3 to -4·1) in Hong Kong, -4·0% (-4·8 to -3·2) in South Korea, -3·5% (-4·0 to -3·0) in Taiwan, and -3·6% (-4·2 to -2·9) in Singapore. The annual estimated change in SMR between people with and without diabetes ranged from -3·0% (95% CI -3·0 to -2·9; US Medicare) to 1·6% (1·4 to 1·7; Lombardy, Italy). Among the 17 data sources with decreasing mortality among people with diabetes, we found a significant SMR increase in five data sources, no significant SMR change in four data sources, and a significant SMR decrease in eight data sources. INTERPRETATION: All-cause mortality in diabetes has decreased in most of the high-income countries we assessed. In eight of 19 data sources analysed, mortality decreased more rapidly in people with diabetes than in those without diabetes. Further longevity gains will require continued improvement in prevention and management of diabetes. FUNDING: US Centers for Disease Control and Prevention, Diabetes Australia Research Program, and Victoria State Government Operational Infrastructure Support Program.

Comprehensive Search for Novel Circulating miRNAs and Axon Guidance Pathway Proteins Associated with Risk of ESKD in Diabetes.

BACKGROUND: Mechanisms underlying the pro gression of diabetic kidney disease to ESKD are not fully understood. METHODS: We performed global microRNA (miRNA) analysis on plasma from two cohorts consisting of 375 individuals with type 1 and type 2 diabetes with late diabetic kidney disease, and targeted proteomics analysis on plasma from four cohorts consisting of 746 individuals with late and early diabetic kidney disease. We examined structural lesions in kidney biopsy specimens from the 105 individuals with early diabetic kidney disease. Human umbilical vein endothelial cells were used to assess the effects of miRNA mimics or inhibitors on regulation of candidate proteins. RESULTS: In the late diabetic kidney disease cohorts, we identified 17 circulating miRNAs, represented by four exemplars (miR-1287-5p, miR-197-5p, miR-339-5p, and miR-328-3p), that were strongly associated with 10-year risk of ESKD. These miRNAs targeted proteins in the axon guidance pathway. Circulating levels of six of these proteins-most notably, EFNA4 and EPHA2-were strongly associated with 10-year risk of ESKD in all cohorts. Furthermore, circulating levels of these proteins correlated with severity of structural lesions in kidney biopsy specimens. In contrast, expression levels of genes encoding these proteins had no apparent effects on the lesions. In in vitro experiments, mimics of miR-1287-5p and miR-197-5p and inhibitors of miR-339-5p and miR-328-3p upregulated concentrations of EPHA2 in either cell lysate, supernatant, or both. CONCLUSIONS: This study reveals novel mechanisms involved in progression to ESKD and points to the importance of systemic factors in the development of diabetic kidney disease. Some circulating miRNAs and axon guidance pathway proteins represent potential targets for new therapies to prevent and treat this condition.

Exploring reasons for state-level variation in incidence of dialysis-requiring acute kidney injury (AKI-D) in the United States.

BACKGROUND: There is considerable state-level variation in the incidence of dialysis-requiring acute kidney injury (AKI-D). However, little is known about reasons for this geographic variation. METHODS: National cross-sectional state-level ecological study based on State Inpatient Databases (SID) and the Behavioral Risk Factor Surveillance System (BRFSS) in 2011. We analyzed 18 states and six chronic health conditions (diabetes mellitus [diabetes], hypertension, chronic kidney disease [CKD], arteriosclerotic heart disease [ASHD], cancer (excluding skin cancer), and chronic obstructive pulmonary disease [COPD]). Associations between each of the chronic health conditions and AKI-D incidence was assessed using Pearson correlation and multiple regression adjusting for mean age, the proportion of males, and the proportion of non-Hispanic whites in each state. RESULTS: The state-level AKI-D incidence ranged from 190 to 1139 per million population. State-level differences in rates of hospitalization with chronic health conditions (mostly < 3-fold difference in range) were larger than the state-level differences in prevalence for each chronic health condition (mostly < 2.5-fold difference in range). A significant correlation was shown between AKI-D incidence and prevalence of diabetes, ASHD, and COPD, as well as between AKI-D incidence and rate of hospitalization with hypertension. In regression models, after adjusting for age, sex, and race, AKI-D incidence was associated with prevalence of and rates of hospitalization with five chronic health conditions--diabetes, hypertension, CKD, ASHD and COPD--and rates of hospitalization with cancer. CONCLUSIONS: Results from this ecological analysis suggest that state-level variation in AKI-D incidence may be influenced by state-level variations in prevalence of and rates of hospitalization with several chronic health conditions. For most of the explored chronic conditions, AKI-D correlated stronger with rates of hospitalizations with the health conditions rather than with their prevalences, suggesting that better disease management strategies that prevent hospitalizations may translate into lower incidence of AKI-D.

A signature of circulating inflammatory proteins and development of end-stage renal disease in diabetes.

Chronic inflammation is postulated to be involved in the development of end-stage renal disease in diabetes, but which specific circulating inflammatory proteins contribute to this risk remain unknown. To study this, we examined 194 circulating inflammatory proteins in subjects from three independent cohorts with type 1 and type 2 diabetes. In each cohort, we identified an extremely robust kidney risk inflammatory signature (KRIS), consisting of 17 proteins enriched in tumor necrosis factor-receptor superfamily members, that was associated with a 10-year risk of end-stage renal disease. All these proteins had a systemic, non-kidney source. Our prospective study findings provide strong evidence that KRIS proteins contribute to the inflammatory process underlying end-stage renal disease development in both types of diabetes. These proteins point to new therapeutic targets and new prognostic tests to identify subjects at risk of end-stage renal disease, as well as biomarkers to measure responses to treatment of diabetic kidney disease.

Prevalence of Diabetic Retinopathy and Associated Mortality Among Diabetic Adults With and Without Chronic Kidney Disease.

PURPOSE: To estimate prevalence and severity of diabetic retinopathy (DR) among U.S. adults with diabetes and with or without chronic kidney disease (CKD), and assess associated risk of mortality. DESIGN: Cross-sectional study with national survey data. METHODS: The cohort included adults ≥40 years old with diabetes in the National Health and Nutrition Examination Surveys (NHANES) 2005-2008. Vital status was determined through December 31, 2011. We defined diabetes as hemoglobin A1c ≥6.5% or self-report and CKD by urinary albumin/creatinine ≥30 mg/g or glomerular filtration rate <60 mL/min/1.73 m2. The main outcomes were DR and mortality. RESULTS: Prevalence of DR was 27.8% (95% CI 24.3-31.7), 36.2% (95%CI 30.1-42.7), and 23.4% (95% CI 19.2-28.1), overall, with and without CKD. Prevalence of vision-threatening DR was 4.2% (95% CI 3.2-5.5), 8.2% (95% CI 5.4-12.2), and 2.0% (95% CI 1.2-3.5), respectively. In a multivariable adjusted model, DR was positively but nonsignificantly associated with CKD (OR = 1.1, 95% CI 0.7-1.7), was 40% higher per 1% increase in hemoglobin A1c (OR = 1.4, 95% CI 1.1-1.6), was 30% higher per 5 years additional diabetes duration (OR = 1.3, 95% CI 1.1-1.5), was 30% higher per 10 mm Hg increase in systolic blood pressure (OR = 1.3, 95% CI 1.1-1.5), and was 6-fold higher with insulin treatment (OR = 6.2, 95% CI 2.6-14.8). Compared with diabetic participants with neither DR nor CKD, those with DR and CKD had a 3.6-fold (95% CI 1.5-9.1) increased adjusted risk for all-cause mortality. CONCLUSIONS: Over one third of persons with diabetes and CKD had DR. The risk of death was higher with than without CKD and DR. Many of the studied risk factors associated with DR are modifiable.

Prevalence of Tuberculosis Disease Among Adult US-Bound Refugees with Chronic Kidney Disease.

The association between chronic kidney disease (CKD) and tuberculosis disease (TB) has been recognized for decades. Recently CKD prevalence is increasing in low- to middle-income countries with high TB burden. Using data from the required overseas medical exam and the recommended US follow-up exam for 444,356 US-bound refugees aged ≥ 18 during 2009-2017, we ran Poisson regression to assess the prevalence of TB among refugees with and without CKD, controlling for sex, age, diabetes, tobacco use, body mass index ( kg/m2), prior residence in camp or non-camp setting, and region of birth country. Of the 1117 (0.3%) with CKD, 21 (1.9%) had TB disease; of the 443,239 who did not have CKD, 3380 (0.8%) had TB. In adjusted analyses, TB was significantly higher among those with than without CKD (prevalence ratio 1.93, 95% CI: 1.26, 2.98, p < 0.01). Healthcare providers attending to refugees need to be aware of this association.

Global trends in diabetes complications: a review of current evidence.

In recent decades, large increases in diabetes prevalence have been demonstrated in virtually all regions of the world. The increase in the number of people with diabetes or with a longer duration of diabetes is likely to alter the disease profile in many populations around the globe, particularly due to a higher incidence of diabetes-specific complications, such as kidney failure and peripheral arterial disease. The epidemiology of other conditions frequently associated with diabetes, including infections and cardiovascular disease, may also change, with direct effects on quality of life, demands on health services and economic costs. The current understanding of the international burden of and variation in diabetes-related complications is poor. The available data suggest that rates of myocardial infarction, stroke and amputation are decreasing among people with diabetes, in parallel with declining mortality. However, these data predominantly come from studies in only a few high-income countries. Trends in other complications of diabetes, such as end-stage renal disease, retinopathy and cancer, are less well explored. In this review, we synthesise data from population-based studies on trends in diabetes complications, with the objectives of: (1) characterising recent and long-term trends in diabetes-related complications; (2) describing regional variation in the excess risk of complications, where possible; and (3) identifying and prioritising gaps for future surveillance and study.

Association of Monoclonal Gammopathy with Progression to ESKD among US Veterans.

BACKGROUND AND OBJECTIVES: Whether patients with monoclonal protein are at a higher risk for progression of kidney disease is not known. The goal of this study was to measure the association of monoclonal protein with progression to ESKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This was a retrospective cohort study of 2,156,317 patients who underwent serum creatinine testing between October 1, 2000 and September 30, 2001 at a Department of Veterans Affairs medical center, among whom 21,898 had paraprotein testing within 1 year before or after cohort entry. Progression to ESKD was measured using linked data from the US Renal Data System. RESULTS: Overall, 1,741,707 cohort members had an eGFR≥60 ml/min per 1.73 m2, 283,988 had an eGFR of 45-59 ml/min per 1.73 m2, 103,123 had an eGFR of 30-44 ml/min per 1.73 m2 and 27,499 had an eGFR of 15-29 ml/min per 1.73 m2. The crude incidence of ESKD ranged from 0.7 to 80 per 1000 person-years from the highest to lowest eGFR category. Patients with low versus preserved eGFR were more likely to be tested for monoclonal protein but no more likely to have a positive test result. In adjusted analyses, a positive versus negative test result was associated with a higher risk of ESKD among patients with an eGFR≥60 ml/min per 1.73 m2 (hazard ratio, 1.67; 95% confidence interval, 1.22 to 2.29) and those with an eGFR of 15-29 ml/min per 1.73 m2 (hazard ratio, 1.38; 95% confidence interval, 1.07 to 1.77), but not among those with an eGFR of 30-59 ml/min per 1.73 m2. Progression to ESKD was attributed to a monoclonal process in 21 out of 76 versus seven out of 174 patients with monoclonal protein and preserved versus severely reduced eGFR at cohort entry. CONCLUSIONS: The detection of monoclonal protein provides little information on ESKD risk for most patients with a low eGFR. Further study is required to better understand factors contributing to a positive association of monoclonal protein with ESKD risk in patients with preserved and severely reduced levels of eGFR.

Trends in Hospitalizations for Acute Kidney Injury - United States, 2000-2014.

Acute kidney injury is a sudden decrease in kidney function with or without kidney damage, occurring over a few hours or days. Diabetes, hypertension, and advanced age are primary risk factors for acute kidney injury. It is increasingly recognized as an in-hospital complication of sepsis, heart conditions, and surgery (1,2). Its most severe stage requires treatment with dialysis. Acute kidney injury is also associated with higher likelihood of long-term care, incidence of chronic kidney disease and hospital mortality, and health care costs (1,2). Although a number of U.S. studies have indicated an increasing incidence of dialysis-treated acute kidney injury since the late 1990s (3), no data are available on national trends in diabetes-related acute kidney injury. To estimate diabetes- and nondiabetes-related acute kidney injury trends, CDC analyzed 2000-2014 data from the National Inpatient Sample (NIS) (4) and the National Health Interview Survey (NHIS) (5). Age-standardized rates of acute kidney injury hospitalizations increased by 139% (from 23.1 to 55.3 per 1,000 persons) among adults with diagnosed diabetes, and by 230% (from 3.5 to 11.7 per 1,000 persons) among those without diabetes. Improving both patient and provider awareness that diabetes, hypertension, and advancing age are frequently associated with acute kidney injury might reduce its occurrence and improve management of the underlying diseases in an aging population.

Colon Cancer Screening among Patients Receiving Dialysis in the United States: Are We Choosing Wisely?

The American Society of Nephrology recommends against routine cancer screening among asymptomatic patients receiving maintenance dialysis on the basis of limited survival benefit. To determine the frequency of colorectal cancer screening among patients on dialysis and the extent to which screening tests were targeted toward patients at lower risk of death and higher likelihood of receiving a kidney transplant, we performed a cohort study of 469,574 Medicare beneficiaries ages ≥50 years old who received dialysis between January 1, 2007 and September 30, 2012. We examined colorectal cancer screening tests according to quartiles of risk of mortality and kidney transplant on the basis of multivariable Cox modeling. Over a median follow-up of 1.5 years, 11.6% of patients received a colon cancer screening test (57.9 tests per 1000 person-years). Incidence rates of colonoscopy, flexible sigmoidoscopy, and fecal occult blood test were 27.9, 0.6, and 29.5 per 1000 person-years, respectively. Patients in the lowest quartile of mortality risk were more likely to be screened than those in the highest quartile (hazard ratio, 1.53; 95% confidence interval, 1.49 to 1.57; 65.1 versus 46.4 tests per 1000 person-years, respectively), amounting to a 33% higher rate of testing. Additionally, compared with patients least likely to receive a transplant, patients most likely to receive a transplant were more likely to be screened (hazard ratio, 1.68; 95% confidence interval, 1.64 to 1.73). Colon cancer screening is being targeted toward patients on dialysis at lowest risk of mortality and highest likelihood of transplantation, but absolute rates are high, suggesting overscreening.

The cost-effectiveness of using chronic kidney disease risk scores to screen for early-stage chronic kidney disease.

BACKGROUND: Better treatment during early stages of chronic kidney disease (CKD) may slow progression to end-stage renal disease and decrease associated complications and medical costs. Achieving early treatment of CKD is challenging, however, because a large fraction of persons with CKD are unaware of having this disease. Screening for CKD is one important method for increasing awareness. We examined the cost-effectiveness of identifying persons for early-stage CKD screening (i.e., screening for moderate albuminuria) using published CKD risk scores. METHODS: We used the CKD Health Policy Model, a micro-simulation model, to simulate the cost-effectiveness of using CKD two published risk scores by Bang et al. and Kshirsagar et al. to identify persons in the US for CKD screening with testing for albuminuria. Alternative risk score thresholds were tested (0.20, 0.15, 0.10, 0.05, and 0.02) above which persons were assigned to receive screening at alternative intervals (1-, 2-, and 5-year) for follow-up screening if the first screening was negative. We examined incremental cost-effectiveness ratios (ICERs), incremental lifetime costs divided by incremental lifetime QALYs, relative to the next higher screening threshold to assess cost-effectiveness. Cost-effective scenarios were determined as those with ICERs less than $50,000 per QALY. Among the cost-effective scenarios, the optimal scenario was determined as the one that resulted in the highest lifetime QALYs. RESULTS: ICERs ranged from $8,823 per QALY to $124,626 per QALY for the Bang et al. risk score and $6,342 per QALY to $405,861 per QALY for the Kshirsagar et al. risk score. The Bang et al. risk score with a threshold of 0.02 and 2-year follow-up screening was found to be optimal because it had an ICER less than $50,000 per QALY and resulted in the highest lifetime QALYs. CONCLUSIONS: This study indicates that using these CKD risk scores may allow clinicians to cost-effectively identify a broader population for CKD screening with testing for albuminuria and potentially detect people with CKD at earlier stages of the disease than current approaches of screening only persons with diabetes or hypertension.

Tumor necrosis factor receptors 1 and 2 are associated with early glomerular lesions in type 2 diabetes.

Elevated serum tumor necrosis factor receptor 1 (TNFR1) and 2 (TNFR2) concentrations are strongly associated with increased risk of end-stage renal disease in type 2 diabetes. However, little is known about the early glomerular structural lesions that develop in patients when these markers are elevated. Here, we examined the relationships between TNFRs and glomerular structure in 83 American Indians with type 2 diabetes. Serum TNFRs and glomerular filtration rate (GFR, iothalamate) were measured during a research exam performed within a median of 0.9 months from a percutaneous kidney biopsy. Associations of TNFRs with glomerular structural variables were quantified by Spearman's correlations and by multivariable linear regression after adjustment for age, gender, diabetes duration, hemoglobin A1c, body mass index, and mean arterial pressure. The baseline mean age was 46 years, median GFR 130 ml/min, median albumin/creatinine ratio 26 mg/g, median TNFR1 1500 pg/ml, and median TNFR2 3284 pg/ml. After multivariable adjustment, TNFR1 and TNFR2 significantly correlated inversely with the percentage of endothelial cell fenestration and the total filtration surface per glomerulus. There were significant positive correlations with mesangial fractional volume, glomerular basement membrane width, podocyte foot process width, and percentage of global glomerular sclerosis. Thus, TNFRs may be involved in the pathogenesis of early glomerular lesions in diabetic nephropathy.

Filtration markers as predictors of ESRD and mortality in Southwestern American Indians with type 2 diabetes.

BACKGROUND: A growing number of serum filtration markers are associated with mortality and end-stage renal disease (ESRD) in adults. Whether ß-trace protein (BTP) and ß2-microglobulin (B2M) are associated with these outcomes in adults with type 2 diabetes is not known. STUDY DESIGN: Longitudinal cohort study. SETTING & PARTICIPANTS: 250 Pima Indians with type 2 diabetes (69% women; mean age, 42 years; mean diabetes duration, 11 years). PREDICTORS: Serum BTP, B2M, and glomerular filtration rate measured by iothalamate clearance (mGFR) or estimated using creatinine (eGFRcr) or cystatin C level (eGFRcys). OUTCOMES & MEASUREMENTS: Incident ESRD and all-cause mortality through December 2013. HRs were reported per interquartile range decrease of the inverse of BTP and B2M (1/BTP and 1/B2M) using Cox regression. Improvement in risk prediction with the addition of BTP or B2M level to established markers (eGFRcys with mGFR or eGFRcr) was evaluated using C statistics, continuous net reclassification improvement, and relative integrated discrimination improvement (RIDI). RESULTS: During a median follow-up of 14 years, 69 participants developed ESRD and 95 died. Both novel markers were associated with ESRD in multivariable models. BTP level remained statistically significant after further adjustment for mGFR (1/BTP, 1.53 [95% CI, 1.01-2.30]; 1/B2M, 1.54 [95% CI, 0.98-2.42]). B2M level was associated with mortality in multivariable models and after further adjustment for mGFR (HR, 2.12; 95% CI, 1.38-3.26). The addition of B2M level to established markers increased the C statistic for mortality but only weakly when assessed by either continuous net reclassification improvement or RIDI; none was improved for ESRD by the addition of these markers. LIMITATIONS: Small sample size, single measurements of markers. CONCLUSIONS: In Pima Indians with type 2 diabetes, BTP and, to a lesser extent, B2M levels were associated with ESRD. B2M level was associated with mortality after adjustment for traditional risk factors and established filtration markers. Further studies are warranted to confirm whether inclusion of B2M level in a multimarker approach leads to improved risk prediction for mortality in this population.

Elevation of circulating TNF receptors 1 and 2 increases the risk of end-stage renal disease in American Indians with type 2 diabetes.

In Caucasians with type 2 diabetes, circulating TNF receptors 1 (TNFR1) and 2 (TNFR2) predict end-stage renal disease (ESRD). Here we examined this relationship in a longitudinal cohort study of American Indians with type 2 diabetes with measured glomerular filtration rate (mGFR, iothalamate) and urinary albumin-to-creatinine ratio (ACR). ESRD was defined as dialysis, kidney transplant, or death attributed to diabetic kidney disease. Age-gender-adjusted incidence rates and incidence rate ratios of ESRD were computed by Mantel-Haenszel stratification. The hazard ratio of ESRD was assessed per interquartile range increase in the distribution of each TNFR after adjusting for baseline age, gender, mean blood pressure, HbA1c, ACR, and mGFR. Among the 193 participants, 62 developed ESRD and 25 died without ESRD during a median follow-up of 9.5 years. The age-gender-adjusted incidence rate ratio of ESRD was higher among participants in the highest versus lowest quartile for TNFR1 (6.6, 95% confidence interval (CI) 3.3-13.3) or TNFR2 (8.8, 95% CI 4.3-18.0). In the fully adjusted model, the risk of ESRD per interquartile range increase was 1.6 times (95% CI 1.1-2.2) as high for TNFR1 and 1.7 times (95% CI 1.2-2.3) as high for TNFR2. Thus, elevated serum concentrations of TNFR1 or TNFR2 are associated with increased risk of ESRD in American Indians with type 2 diabetes after accounting for traditional risk factors including ACR and mGFR.

Awareness of kidney disease among US adults: Findings from the 2011 behavioral risk factor surveillance system.

BACKGROUND: The prevalence of chronic kidney disease as measured by biomarkers is increasing, but the recognition for this condition remains low in the USA. Little is known about the awareness of kidney disease at the state level. METHODS: Data from 490,302 adults aged 18 years or older in all 50 states as well as the District of Columbia who participated in the 2011 Behavioral Risk Factor Surveillance System were analyzed. Kidney disease diagnosis, a measure of individual awareness, was ascertained by participants' self-report in the telephone survey. Prevalence ratios of self-reported kidney disease in subpopulations were estimated and tested using log-linear regression analyses with a robust variance estimator. RESULTS: The unadjusted prevalence of self-reported kidney disease was estimated to be 2.5%. After adjustment for age and all other selected covariates, Hispanics had a higher prevalence than non-Hispanic whites (adjusted prevalence ratio 1.2, 95% CI 1.0-1.4). Persons who were unemployed (adjusted prevalence ratio 1.4, 95% CI 1.2-1.5) had a higher prevalence than those who were employed. Persons who had hypertension (adjusted prevalence ratio 1.9, 95% CI 1.7-2.1), diabetes (adjusted prevalence ratio 1.7, 95% CI 1.5-1.8), cardiovascular disease (coronary heart disease, myocardial infarction or stroke; adjusted prevalence ratio 1.5, 95% CI 1.4-1.6) or cancer (adjusted prevalence ratio 1.5, 95% CI 1.3-1.6) had a higher prevalence of self-reported kidney disease than those without these conditions. CONCLUSION: The overall awareness of kidney disease was low in the general population. Efforts are needed to promote the awareness and early detection of kidney disease in public health services and clinical practice.

Comparison of serum cystatin C, serum creatinine, measured GFR, and estimated GFR to assess the risk of kidney failure in American Indians with diabetic nephropathy.

BACKGROUND: We compared values of baseline serum cystatin C (SCysC), serum creatinine (SCr), and measured glomerular filtration rate (mGFR) for predicting end-stage renal disease (ESRD) in patients with type 2 diabetes and elevated albuminuria. STUDY DESIGN: Observational longitudinal study. SETTING & PARTICIPANTS: Pima Indians with type 2 diabetes and elevated albumin-creatinine ratio (ACR ≥30 mg/g). PREDICTORS: Baseline SCysC, SCr, and mGFR. OUTCOMES & MEASUREMENTS: Individuals were followed up from their first examination with diabetes and ACR ≥30 mg/g until December 2010, onset of ESRD, or death, whichever came first. Incidence rates adjusted for age and sex were computed by Mantel-Haenszel stratification. The abilities of SCysC, SCr, and mGFR values to predict ESRD were compared with receiver operating characteristic curves. RESULTS: Of 234 Pima Indians with a mean age of 42.8 years who were followed up for a median of 10.7 (range, 0.6-21.3) years, 68 (29%) developed ESRD. The incidence of ESRD was significantly higher in patients in the lowest versus highest tertile of 1/SCysC (incidence rate ratio, 2.43; 95% CI, 1.31-4.50). By contrast, mGFR and 1/SCr had J-shaped associations with ESRD. In unadjusted analyses, 1/SCysC had the highest area under the receiver operating characteristic curve (AUROC; 0.719 ± 0.035) and mGFR had the lowest (0.585 ± 0.042; P < 0.001); the AUROC for 1/SCr was intermediate (0.672 ± 0.040; P = 0.1 and P = 0.03 vs 1/SCysC and mGFR, respectively). In analyses adjusted for age, sex, diabetes duration, height, weight, hemoglobin A1c level, and ACR, 1/SCysC had the highest AUROC (0.845 ± 0.026). Models with mGFR or 1/SCr alone had similar AUROCs (P = 0.9) and both were lower than the model with 1/SCysC alone (P = 0.02 and P = 0.03, respectively). LIMITATIONS: The predictive values of the filtration markers are limited to the extent that their precision is based on a single measurement. CONCLUSIONS: SCysC level was a better predictor of ESRD than mGFR or SCr level in Pima Indians with type 2 diabetes and elevated albuminuria.