Association Between Renin-Angiotensin System Blockade Discontinuation and All-Cause Mortality Among Persons With Low Estimated Glomerular Filtration Rate

IMPORTANCE

It is uncertain whether and when angiotensin-converting enzyme inhibitor (ACE-I) and angiotensin II receptor blocker (ARB) treatment should be discontinued in individuals with low estimated glomerular filtration rate (eGFR).

OBJECTIVE

To investigate the association of ACE-I or ARB therapy discontinuation after eGFR decreases to below 30 mL/min/1.73 m2 with the risk of mortality, major adverse cardiovascular events (MACE), and end-stage kidney disease (ESKD).

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, propensity score-matched cohort study included 3909 patients from an integrated health care system that served rural areas of central and northeastern Pennsylvania. Patients who initiated ACE-I or ARB therapy from January 1, 2004, to December 31, 2018, and had an eGFR decrease to below 30 mL/min/1.73 m2 during therapy were enrolled, with follow-up until January 25, 2019.

EXPOSURES

Individuals were classified based on whether they discontinued ACE-I or ARB therapy within 6 months after an eGFR decrease to below 30 mL/min/1.73 m2.

MAIN OUTCOMES AND MEASURES

The association between ACE-I or ARB therapy discontinuation and mortality during the subsequent 5 years was assessed using multivariable Cox proportional hazards regression models, adjusting for patient characteristics at the time of the eGFR decrease in a propensity score-matched sample. Secondary outcomes included MACE and ESKD.

RESULTS

Of the 3909 individuals receiving ACE-I or ARB treatment who experienced an eGFR decrease to below 30 mL/min/1.73 m2 (2406 [61.6%] female; mean [SD] age, 73.7 [12.6] years), 1235 discontinued ACE-I or ARB therapy within 6 months after the eGFR decrease and 2674 did not discontinue therapy. A total of 434 patients (35.1%) who discontinued ACE-I or ARB therapy and 786 (29.4%) who did not discontinue therapy died during a median follow-up of 2.9 years (interquartile range, 1.3-5.0 years). In the propensity score-matched sample of 2410 individuals, ACE-I or ARB therapy discontinuation was associated with a higher risk of mortality (hazard ratio [HR], 1.39; 95% CI, 1.20-1.60]) and MACE (HR, 1.37; 95% CI, 1.20-1.56), but no statistically significant difference in the risk of ESKD was found (HR, 1.19; 95% CI, 0.86-1.65).

CONCLUSIONS AND RELEVANCE

The findings suggest that continuing ACE-I or ARB therapy in patients with declining kidney function may be associated with cardiovascular benefit without excessive harm of ESKD.

Particulate Matter and Albuminuria, Glomerular Filtration Rate, and Incident CKD

BACKGROUND AND OBJECTIVES

Exposure to particulate matter (PM) <2.5 μm in aerodynamic diameter (PM2.5) has been linked to detrimental health effects. This study aimed to describe the relationship between long-term PM2.5 exposure and kidney disease, including eGFR, level of albuminuria, and incident CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study included 10,997 participants from the Atherosclerosis Risk in Communities cohort who were followed from 1996-1998 through 2016. Monthly mean PM2.5 concentrations (μg/m3) were estimated at geocoded participant addresses using geographic information system-based, spatiotemporal generalized additive mixed models-including geospatial covariates such as land use-and then averaged over the 12-month period preceding participant examination. Covariate-adjusted, cross-sectional associations of PM2.5, baseline eGFR, and urinary albumin-creatinine ratio (UACR) were estimated using linear regression. PM2.5 and incident CKD (defined as follow-up eGFR <60 ml/min per 1.73 m2 with ≥25% eGFR decline relative to baseline, CKD-related hospitalization or death based on International Classification of Diseases 9/10 codes, or development of ESKD) associations were estimated using Cox proportional hazards regression. Modeling was stratified by study site, and stratum-specific estimates were combined using random-effects meta-analyses.

RESULTS

Baseline mean participant age was 63 (±6) years and eGFR was 86 (±16) ml/min per 1.73 m2. There was no significant PM2.5-eGFR association at baseline. Each 1-μg/m3 higher annual average PM2.5 was associated with higher UACR after adjusting for demographics, socioeconomic status, and clinical covariates (percentage difference, 6.6%; 95% confidence interval [95% CI], 2.6% to 10.7%). Each 1-μg/m3 higher annual average PM2.5 was associated with a significantly higher risk of incident CKD (hazard ratio, 1.05; 95% CI, 1.01 to 1.10).

CONCLUSIONS

Exposure to higher annual average PM2.5 concentrations was associated with a higher level of albuminuria and higher risk for incident CKD in a community-based cohort.

Incident Hospitalization with Major Cardiovascular Diseases and Subsequent Risk of ESKD: Implications for Cardiorenal Syndrome

BACKGROUND

Cardiorenal syndrome is a well known concept, bolstered by extensive investigations of CKD as a risk factor of cardiovascular disease. However, data on whether cardiovascular disease increases long-term risk of ESKD are sparse.

METHODS

We assessed the association of incident hospitalization with major cardiovascular diseases (heart failure, atrial fibrillation, coronary heart disease, and stroke) with subsequent risk of ESKD among individuals enrolled in the Atherosclerosis Risk in Communities study; the analysis included 9047 individuals without prevalent cardiovascular disease at their fourth study visit. Each relevant incident cardiovascular disease event was entered into multivariable Cox proportional hazard models as a time-varying exposure to estimate hazard ratios.

RESULTS

During a median follow-up of 17.5 years, there were 2598 cases of hospitalization with cardiovascular disease (heart failure, n=1269; atrial fibrillation, n=1337; coronary heart disease, n=696; and stroke, n=559) and 210 cases of incident ESKD. The incidence of major cardiovascular disease was associated with increased risk of ESKD, with the highest risk for heart failure (hazard ratio, 11.40; 95% confidence interval, 8.38 to 15.50), followed by coronary heart disease, atrial fibrillation, and stroke. When we analyzed heart failure with preserved ejection fraction and heart failure with reduced ejection fraction separately, the risk was nominally higher for heart failure with preserved ejection fraction.

CONCLUSIONS

Major incident cardiovascular disease events were associated with ESKD, independent of kidney risk factors. In particular, heart failure showed a very strong association with ESKD. Our findings highlight the importance of monitoring and managing kidney disease in patients with cardiovascular disease. The potentially distinct contribution to ESKD of heart failure with preserved versus reduced ejection fraction deserves future investigation.

GSTM1 Deletion Exaggerates Kidney Injury in Experimental Mouse Models and Confers the Protective Effect of Cruciferous Vegetables in Mice and Humans

BACKGROUND

GSTM1 encodes glutathione S-transferase μ-1 (GSTM1), which belongs to a superfamily of phase 2 antioxidant enzymes. The highly prevalent GSTM1 deletion variant is associated with kidney disease progression in human cohorts: the African American Study of Kidney Disease and Hypertension and the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

We generated a Gstm1 knockout mouse line to study its role in a CKD model (involving subtotal nephrectomy) and a hypertension model (induced by angiotensin II). We examined the effect of intake of cruciferous vegetables and GSTM1 genotypes on kidney disease in mice as well as in human ARIC study participants. We also examined the importance of superoxide in the mediating pathways and of hematopoietic GSTM1 on renal inflammation.

RESULTS

Gstm1 knockout mice displayed increased oxidative stress, kidney injury, and inflammation in both models. The central mechanism for kidney injury is likely mediated by oxidative stress, because treatment with Tempol, an superoxide dismutase mimetic, rescued kidney injury in knockout mice without lowering BP. Bone marrow crosstransplantation revealed that Gstm1 deletion in the parenchyma, and not in bone marrow-derived cells, drives renal inflammation. Furthermore, supplementation with cruciferous broccoli powder rich in the precursor to antioxidant-activating sulforaphane significantly ameliorated kidney injury in Gstm1 knockout, but not wild-type mice. Similarly, among humans (ARIC study participants), high consumption of cruciferous vegetables was associated with fewer kidney failure events compared with low consumption, but this association was observed primarily in participants homozygous for the GSTM1 deletion variant.

CONCLUSIONS

Our data support a role for the GSTM1 enzyme in the modulation of oxidative stress, inflammation, and protective metabolites in CKD.

Alcohol Consumption and Incident Kidney Disease: Results From the Atherosclerosis Risk in Communities Study

OBJECTIVE(S)

Moderate alcohol consumption has been found to be associated with lower risk of coronary heart disease and myocardial infarction, which share similar risk factors and pathophysiology with chronic kidney disease (CKD). However, there is inconsistent evidence on the association between alcohol consumption and CKD.

DESIGN AND METHODS

We conducted a prospective analysis of 12,692 participants aged 45-64 years from the Atherosclerosis Risk in Communities (ARIC) study. We categorized participants into 6 alcohol consumption categories: never drinkers, former drinkers, ≤1 drink per week, 2 to 7 drinks per week, 8 to 14 drinks per week, and ≥15 drinks per week based on food frequency questionnaire responses at visit 1 (1987-1989). Incident CKD was defined as estimated glomerular filtration rate <60 mL/minute/1.73 m2 accompanied by ≥25% estimated glomerular filtration rate decline, a kidney disease-related hospitalization or death or end-stage renal disease.

RESULTS

During a median follow-up of 24 years, there were 3,664 cases of incident CKD. Current drinkers were more likely to be men, whites, and to have a higher income level and education level. After adjusting for total energy intake, age, sex, race-center, income, education level, health insurance, smoking, and physical activity, there was no significant association between being a former drinker and risk of incident CKD. Participants who drank ≤1 drink per week, 2 to 7 drinks per week, 8 to 14 drinks per week, and ≥15 drinks per week had, respectively, a 12% (hazard ratio [HR]: 0.88, 95% confidence interval [CI]: 0.79-0.97), 20% (HR: 0.80, 95% CI: 0.72-0.89), 29% (HR: 0.71, 95% CI: 0.62-0.83), and 23% (HR: 0.77, 95% CI: 0.65-0.91) lower risk of CKD compared with never drinkers.

CONCLUSION(S)

Consuming a low or moderate amount of alcohol may lower the risk of developing CKD. Therefore, moderate consumption of alcohol may not likely be harmful to the kidneys.

Development of Risk Prediction Equations for Incident Chronic Kidney Disease

IMPORTANCE

Early identification of individuals at elevated risk of developing chronic kidney disease (CKD) could improve clinical care through enhanced surveillance and better management of underlying health conditions.

OBJECTIVE

To develop assessment tools to identify individuals at increased risk of CKD, defined by reduced estimated glomerular filtration rate (eGFR).

DESIGN, SETTING, AND PARTICIPANTS

Individual-level data analysis of 34 multinational cohorts from the CKD Prognosis Consortium including 5 222 711 individuals from 28 countries. Data were collected from April 1970 through January 2017. A 2-stage analysis was performed, with each study first analyzed individually and summarized overall using a weighted average. Because clinical variables were often differentially available by diabetes status, models were developed separately for participants with diabetes and without diabetes. Discrimination and calibration were also tested in 9 external cohorts (n = 2 253 540).

EXPOSURES

Demographic and clinical factors.

MAIN OUTCOMES AND MEASURES

Incident eGFR of less than 60 mL/min/1.73 m2.

RESULTS

Among 4 441 084 participants without diabetes (mean age, 54 years, 38% women), 660 856 incident cases (14.9%) of reduced eGFR occurred during a mean follow-up of 4.2 years. Of 781 627 participants with diabetes (mean age, 62 years, 13% women), 313 646 incident cases (40%) occurred during a mean follow-up of 3.9 years. Equations for the 5-year risk of reduced eGFR included age, sex, race/ethnicity, eGFR, history of cardiovascular disease, ever smoker, hypertension, body mass index, and albuminuria concentration. For participants with diabetes, the models also included diabetes medications, hemoglobin A1c, and the interaction between the 2. The risk equations had a median C statistic for the 5-year predicted probability of 0.845 (interquartile range [IQR], 0.789-0.890) in the cohorts without diabetes and 0.801 (IQR, 0.750-0.819) in the cohorts with diabetes. Calibration analysis showed that 9 of 13 study populations (69%) had a slope of observed to predicted risk between 0.80 and 1.25. Discrimination was similar in 18 study populations in 9 external validation cohorts; calibration showed that 16 of 18 (89%) had a slope of observed to predicted risk between 0.80 and 1.25.

CONCLUSIONS AND RELEVANCE

Equations for predicting risk of incident chronic kidney disease developed from more than 5 million individuals from 34 multinational cohorts demonstrated high discrimination and variable calibration in diverse populations. Further study is needed to determine whether use of these equations to identify individuals at risk of developing chronic kidney disease will improve clinical care and patient outcomes.

Discontinuation of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers in Chronic Kidney Disease

OBJECTIVE

To assess the patterns of angiotensin converting enzyme inhibitors and angiotensin receptor blockers (ACE-I/ARB) discontinuation in the setting of chronic kidney disease (CKD) progression in real-world clinical practice.

PATIENTS AND METHODS

We identified incident ACE-I/ARB users with a baseline estimated glomerular filtration rate (eGFR) ≥15 mL/min/1.73 m2 and without end-stage renal disease in the Geisinger Health System between January 1, 2004, and December 31, 2015. We investigated the associations of CKD stage, hospitalizations with and without acute kidney injury (AKI), serum potassium, bicarbonate level, thiazide, and loop diuretic use with ACE-I/ARB discontinuation.

RESULTS

Among the 53,912 ACE-I/ARB users, the mean age was 59.9 years, and 50.6% were female. More than half of users discontinued ACE-I/ARB within 5 years of therapy initiation. The risk of ACE-I/ARB discontinuation increased with more advanced CKD stage. For example, patients who initiated ACE-I/ARB with CKD stage G4 (eGFR: 15-29 mL/min/1.73 m2) were 2.09-fold (95% CI, 1.87-2.34) more likely to discontinue therapy than those with eGFR ≥ 90 mL/min/1.73 m2. Potassium level greater than 5.3 mEq/L, systolic blood pressure ≤ 90 mm Hg, bicarbonate level < 22 mmol/L, and intervening hospitalization-particularly AKI-related-were also strong risk factors for ACE-I/ARB discontinuation. Thiazide diuretic use was associated with lower risk, whereas loop diuretic use was associated with higher risk of discontinuation.

CONCLUSION

In a real-world cohort, discontinuation of ACE-I/ARB was common, particularly in patients with lower eGFR. Hyperkalemia, hypotension, low bicarbonate level, and hospitalization (AKI-related, in particular) were associated with a higher risk of ACE-I/ARB discontinuation. Additional studies are needed to evaluate the risk-benefit balance of discontinuing ACE-I/ARB in the setting of CKD progression.

Associations of Opioid Prescriptions with Death and Hospitalization across the Spectrum of Estimated GFR

BACKGROUND AND OBJECTIVES

Most opioids undergo kidney excretion. The goal of this study was to evaluate opioid-associated risks of death and hospitalization across the range of eGFR.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study population included adult primary care patients in Geisinger Health (Danville, PA) between 2008 and 2017. People receiving their first opioid prescription were propensity matched to people receiving NSAIDS (and, in sensitivity analysis, gabapentinoids) and the risk of death and hospitalization were compared, classifying opioid medication exposure as time-varying daily oral morphine milligram equivalents (MMEs) across time-varying eGFR.

RESULTS

The propensity-matched cohort included 46,246 patients prescribed either opioids or NSAIDs between 2008 and 2017 (mean [SD] age, 54 [16] years; 56% female; 3% of black race). Prescriptions for 1-59 and ≥60 MMEs were associated with higher risk of death (HR, 1.70; 95% CI, 1.41 to 2.05 for 1-59 MMEs; HR, 2.25; 95% CI, 1.82 to 2.79 for ≥60 MMEs) and hospitalization (HR, 1.38; 95% CI, 1.30 to 1.46 for 1-59 MMEs; HR, 1.68; 95% CI, 1.56 to 1.81 for ≥60 MMEs) compared with NSAID prescriptions, when evaluated at eGFR 80 ml/min per 1.73 m². The relative risk of death associated with ≥60 MMEs was higher at lower GFR (e.g., eGFR, 40 ml/min per 1.73 m²; HR, 3.94; 95% CI, 2.70 to 5.75; P for interaction, 0.01). When gabapentinoids were used as the comparison medication, only ≥60 MMEs were significantly associated with higher risk of death (HR, 2.72; 95% CI, 1.71 to 4.34), although both 1-59 and ≥60 MMEs were associated with risk of hospitalization (HR, 1.22; 95% CI, 1.04 to 1.43 for 1-59 MMEs; HR, 1.54; 95% CI, 1.28 to 1.86 for ≥60 MMEs).

CONCLUSIONS

The receipt of prescription opioids was associated with a higher risk of death and hospitalization compared with other pain medications, particularly with higher doses and at lower eGFR.

Chronic Kidney Disease Diagnosis and Management: A Review

Importance

Chronic kidney disease (CKD) is the 16th leading cause of years of life lost worldwide. Appropriate screening, diagnosis, and management by primary care clinicians are necessary to prevent adverse CKD-associated outcomes, including cardiovascular disease, end-stage kidney disease, and death.

Observations

Defined as a persistent abnormality in kidney structure or function (eg, glomerular filtration rate [GFR] <60 mL/min/1.73 m2 or albuminuria ≥30 mg per 24 hours) for more than 3 months, CKD affects 8% to 16% of the population worldwide. In developed countries, CKD is most commonly attributed to diabetes and hypertension. However, less than 5% of patients with early CKD report awareness of their disease. Among individuals diagnosed as having CKD, staging and new risk assessment tools that incorporate GFR and albuminuria can help guide treatment, monitoring, and referral strategies. Optimal management of CKD includes cardiovascular risk reduction (eg, statins and blood pressure management), treatment of albuminuria (eg, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers), avoidance of potential nephrotoxins (eg, nonsteroidal anti-inflammatory drugs), and adjustments to drug dosing (eg, many antibiotics and oral hypoglycemic agents). Patients also require monitoring for complications of CKD, such as hyperkalemia, metabolic acidosis, hyperphosphatemia, vitamin D deficiency, secondary hyperparathyroidism, and anemia. Those at high risk of CKD progression (eg, estimated GFR <30 mL/min/1.73 m2, albuminuria ≥300 mg per 24 hours, or rapid decline in estimated GFR) should be promptly referred to a nephrologist.

Conclusions and Relevance

Diagnosis, staging, and appropriate referral of CKD by primary care clinicians are important in reducing the burden of CKD worldwide.

Neighborhood Poverty and Sex Differences in Live Donor Kidney Transplant Outcomes in the United States

BACKGROUND

Neighborhood poverty has been associated with worse outcomes after live donor kidney transplantation (LDKT), and prior work suggests that women with kidney disease may be more susceptible to the negative influence of poverty than men. As such, our goal was to examine whether poverty differentially affects women in influencing LDKT outcomes.

METHODS

Using data from the Scientific Registry of Transplant Recipients and US Census, we performed multivariable Cox regression to compare outcomes among 18 955 women and 30 887 men who received a first LDKT in 2005-2014 with follow-up through December 31, 2016.

RESULTS

Women living in poor (adjusted hazard ratio [aHR], 1.30; 95% confidence interval [CI], 1.13-1.50) and middle-income (aHR, 1.26; 95% CI, 1.14-1.40) neighborhoods had higher risk of graft loss than men, but there were no differences in wealthy areas (aHR, 1.07; 95% CI, 0.88-1.29). Women living in wealthy (aHR, 0.71; 95% CI, 0.59-0.87) and middle-income (aHR, 0.82; 95% CI, 0.74-0.92) neighborhoods incurred a survival advantage over men, but there were no statistically significant differences in mortality in poor areas (aHR, 0.85; 95% CI, 0.72-1.01).

CONCLUSIONS

Given our findings that poverty is more strongly associated with graft loss in women, targeted efforts are needed to specifically address mechanisms driving these disparities in LDKT outcomes.

Lifetime Risk of Lower-Extremity Peripheral Artery Disease Defined by Ankle-Brachial Index in the United States

Background There are no available lifetime risk estimates of lower-extremity peripheral artery disease (PAD). Methods and Results Using data from 6 US community-based cohorts and the vital statistics, we estimated the prevalence and incidence of PAD, defined as an ankle-brachial index < 0.90, at each year of age from birth to 80 years for white, black, and Hispanic men and women. Then, we used Markov Monte Carlo simulations in a simulated cohort of 100 000 individuals to estimate lifetime risk of PAD. On the basis of odds ratios of PAD for traditional atherosclerotic risk factors (eg, diabetes mellitus and smoking), we developed a calculator providing residual lifetime risk of PAD. In an 80-year horizon, lifetime risks of PAD were 30.0% in black men and 27.6% in black women, but ≈19% in white men and women and ≈22% in Hispanic men and women. From another perspective, 9% of blacks were estimated to develop PAD by 60 years of age, while the same proportion was seen at ≈70 years for whites and Hispanics. The residual lifetime risk within the same race/ethnicity varied by 3.5- to 5-fold according to risk factors (eg, residual lifetime risk in 45-year-old black men was 19.9% when current smoking, diabetes mellitus, and history of cardiovascular disease were absent versus 70.4% when all were present). Conclusions In the United States, ≈30% of blacks are estimated to develop PAD during their lifetime, whereas the corresponding estimate is ≈20% for whites and Hispanics. The residual lifetime risk within the same race/ethnicity substantially varies according to traditional risk factors.

Dietary patterns and risk of incident chronic kidney disease: the Atherosclerosis Risk in Communities study

BACKGROUND

Adherence to healthy dietary patterns, measured by the Healthy Eating Index (HEI), Alternative Healthy Eating Index (AHEI), and alternate Mediterranean diet (aMed) scores, is associated with a reduced risk of cardiovascular disease. The association between these scores and chronic kidney disease (CKD) is undetermined.

OBJECTIVE

We aimed to estimate the association between the HEI, AHEI, and aMed scores and risk of incident CKD.

METHODS

We conducted a prospective analysis in 12,155 participants aged 45-64 y from the Atherosclerosis Risk in Communities (ARIC) Study. We calculated HEI-2015, AHEI-2010, and aMed scores for each participant and categorized them into quintiles of each dietary score. Incident CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2 accompanied by ≥25% decline in estimated glomerular filtration rate, a kidney disease-related hospitalization or death, or end-stage renal disease. We used cause-specific hazard models to estimate risk of CKD from the quintile of the dietary score through to 31 December 2017.

RESULTS

There were 3980 cases of incident CKD over a median follow-up of 24 y. Participants who had higher adherence to the HEI-2015, AHEI-2010, and aMed scores were more likely to be female, have higher educational attainment, higher income level, be nonsmokers, more physically active, and diabetic compared with participants who scored lower. All 3 dietary scores were associated with lower CKD risk (P-trend < 0.001). Participants who were in the highest quintile of HEI-2015 score had a 17% lower risk of CKD (HR: 0.83; 95% CI: 0.74, 0.92) compared with participants in the lowest quintile. Those in quintile 5 of AHEI-2010 and aMed scores, respectively, had a 20% and 13% lower risk of CKD compared with those in quintile 1.

CONCLUSION

Higher adherence to healthy dietary patterns during middle age was associated with lower risk of CKD.

Association Between Hypertension and Kidney Function Decline: The Atherosclerosis Risk in Communities (ARIC) Study

RATIONALE & OBJECTIVE

The relationship between hypertension, antihypertension medication use, and change in glomerular filtration rate (GFR) over time among individuals with preserved GFR requires investigation.

STUDY DESIGN

Observational study.

SETTING & PARTICIPANTS

14,854 participants from the Atherosclerosis Risk in Communities (ARIC) Study.

PREDICTORS

Baseline hypertension status (1987-1989) was categorized according to the 2017 American College of Cardiology/American Heart Association Clinical Practice Guideline as normal blood pressure, elevated blood pressure, stage 1 hypertension, stage 2 hypertension without medication, or stage 2 hypertension with medication.

OUTCOMES

Slope of estimated GFR (eGFR) at 5 study visits over 30 years.

ANALYTICAL APPROACH

Mixed models with random intercepts and random slopes were fit to evaluate the association between baseline hypertension status and slope of eGFR.

RESULTS

At baseline, 13.2%, 7.3%, and 19.4% of whites and 15.8%, 14.9%, and 39.9% of African Americans had stage 1 hypertension, stage 2 hypertension without medication, and stage 2 hypertension with medication. Compared with those with normal blood pressure, the annual eGFR decline was greater in people with higher blood pressure (whites: elevated blood pressure, -0.11mL/min/1.73m2; stage 1 hypertension, -0.15mL/min/1.73m2; stage 2 hypertension without medication, -0.36mL/min/1.73m2; stage 2 hypertension with medication, -0.17mL/min/1.73m2; African Americans: elevated blood pressure, -0.21mL/min/1.73m2; stage 1 hypertension, -0.16mL/min/1.73m2; stage 2 hypertension without medication, -0.50mL/min/1.73m2; stage 2 hypertension with medication, -0.16mL/min/1.73m2). The 30-year predicted probabilities of developing chronic kidney disease stage G3a+with normal blood pressure, elevated blood pressure, stage 1 hypertension, stage 2 hypertension without medication, or stage 2 hypertension with medication among whites were 54.4%, 61.6%, 64.7%, 78.1%, and 70.9%, respectively, and 55.4%, 62.8%, 60.9%, 76.1%, and 66.6% among African Americans.

LIMITATIONS

Slope estimated using a maximum of 5 eGFR assessments; differential loss to follow-up.

CONCLUSIONS

Compared to normotension, baseline hypertension status was associated with faster kidney function decline over 30-year follow-up in a general population cohort. This difference was attenuated among people using antihypertensive medications.

Change in Albuminuria and GFR as End Points for Clinical Trials in Early Stages of CKD: A Scientific Workshop Sponsored by the National Kidney Foundation in Collaboration With the US Food and Drug Administration and European Medicines Agency

The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) are currently willing to consider a 30% to 40% glomerular filtration rate (GFR) decline as a surrogate end point for kidney failure for clinical trials of kidney disease progression under appropriate conditions. However, these end points may not be practical for early stages of kidney disease. In March 2018, the National Kidney Foundation sponsored a scientific workshop in collaboration with the FDA and EMA to evaluate changes in albuminuria or GFR as candidate surrogate end points. Three parallel efforts were presented: meta-analyses of observational studies (cohorts), meta-analyses of clinical trials, and simulations of trial design. In cohorts, after accounting for measurement error, relationships between change in urinary albumin-creatinine ratio (UACR) or estimated GFR (eGFR) slope and the clinical outcome of kidney disease progression were strong and consistent. In trials, the posterior median R² of treatment effects on the candidate surrogates with the clinical outcome was 0.47 (95% Bayesian credible interval [BCI], 0.02-0.96) for early change in UACR and 0.72 (95% BCI, 0.05-0.99) when restricted to baseline UACR>30mg/g, and 0.97 (95% BCI, 0.78-1.00) for total eGFR slope at 3 years and 0.96 (95% BCI, 0.63-1.00) for chronic eGFR slope (ie, the slope excluding the first 3 months from baseline, when there might be acute changes in eGFR). The magnitude of the relationships of changes in the candidate surrogates with risk for clinical outcome was consistent across cohorts and trials: a UACR reduction of 30% or eGFR slope reduction by 0.5 to 1.0mL/min/1.73m² per year were associated with an HR of ∼0.7 for the clinical outcome in cohorts and trials. In simulations, using GFR slope as an end point substantially reduced the required sample size and duration of follow-up compared with the clinical end point when baseline eGFR was high, treatment effects were uniform, and there was no acute effect of the treatment. We conclude that both early change in albuminuria and GFR slope fulfill criteria for surrogacy for use as end points in clinical trials for chronic kidney disease progression under certain conditions, with stronger support for change in GFR than albuminuria. Implementation requires understanding conditions under which each surrogate is likely to perform well and restricting its use to those settings.

APOL1 Kidney Risk Variants and Cardiovascular Disease: An Individual Participant Data Meta-Analysis

BACKGROUND

Two coding variants in the apo L1 gene (APOL1) are strongly associated with kidney disease in blacks. Kidney disease itself increases the risk of cardiovascular disease, but whether these variants have an independent direct effect on the risk of cardiovascular disease is unclear. Previous studies have had inconsistent results.

METHODS

We conducted a two-stage individual participant data meta-analysis to assess the association of APOL1 kidney-risk variants with adjudicated cardiovascular disease events and death, independent of kidney measures. The analysis included 21,305 blacks from eight large cohorts.

RESULTS

Over 8.9±5.0 years of follow-up, 2076 incident cardiovascular disease events occurred in the 16,216 participants who did not have cardiovascular disease at study enrollment. In fully-adjusted analyses, individuals possessing two APOL1 kidney-risk variants had similar risk of incident cardiovascular disease (coronary heart disease, myocardial infarction, stroke and heart failure; hazard ratio 1.11, 95% confidence interval, 0.96 to 1.28) compared to individuals with zero or one kidney-risk variant. The risk of coronary heart disease, myocardial infarction, stroke and heart failure considered individually was also comparable by APOL1 genotype. APOL1 genotype was also not associated with death. There was no difference in adjusted associations by level of kidney function, age, diabetes status, or body-mass index.

CONCLUSIONS

In this large, two-stage individual participant data meta-analysis, APOL1 kidney-risk variants were not associated with incident cardiovascular disease or death independent of kidney measures.

Coffee consumption and liver-related hospitalizations and deaths in the ARIC study

BACKGROUND/OBJECTIVES

Coffee consumption has been found to be associated with reduced risk of chronic conditions such as liver disease. However, less is known about the association between coffee and liver-related hospitalizations and deaths.

SUBJECTS/METHODS

We conducted a prospective analysis on 14,208 participants aged 45-64 years from the Atherosclerosis Risk in Communities (ARIC) study. Coffee consumption (cups/day) was assessed using food frequency questionnaires at visit 1 (1987-89) and visit 3 (1993-95). Liver-related hospitalizations were defined as a hospitalization with any International Classification of Diseases, Ninth Revision (ICD-9) code related to liver disease identified through cohort surveillance. Liver-related death was defined as any death with a liver disease ICD-9 code listed anywhere on the death certificate form.

RESULTS

There were 833 incident cases of liver-related hospitalizations over a median follow-up of 24 years and 152 liver-related deaths over a median follow-up of 25 years. Participants who were in the highest category of coffee consumption (≥ 3 cups/day) were more likely to be men, whites, current smokers, and current alcohol drinkers. In our fully adjusted model, consuming ≥ 3 cups/day of coffee was significantly associated with a reduced risk of liver-related hospitalizations compared with never drinkers (hazard ratio: 0.79, 95% CI: 0.63-0.99). There were no significant associations between coffee consumption and liver-related deaths after adjusting for covariates.

CONCLUSIONS

Coffee drinkers may be at lower risk for liver-related hospitalizations. This supports current evidence that low and moderate levels of coffee may be protective to the liver.

Hospitalization Risk among Older Adults with Chronic Kidney Disease

INTRODUCTION

Chronic kidney disease (CKD) risk staging is based on estimated glomerular filtration rate (eGFR) and albumin-creatinine ratio (ACR). However, the relationship between all-cause hospitalization risk and the current CKD staging system has not been well studied among older adults, despite a high prevalence of CKD and a high risk of hospitalization in old age.

METHODS

Among 4,766 participants of the Atherosclerosis Risk in Communities study, CKD was staged according to Kidney Disease Improving Global Outcomes (KDIGO) criteria, using creatinine-based eGFR (eGFRcr) and ACR. Incidence rates of all-cause hospitalization associated with each CKD risk group were analyzed using negative binomial regression. Additionally, cause-specific hospitalization risks for cardiovascular, infectious, kidney, and other diseases were estimated. The impacts of using cystatin C-based eGFR (eGFRcys) to estimate the prevalence of CKD and risks of hospitalization were also quantified.

RESULTS

Participants experienced 5,548 hospitalizations and 29% had CKD. Hospitalization rates per 1,000 person-years according to KDIGO risk categories were 208-223 ("low risk"), 288-376 ("moderately increased risk"), 363-548 ("high risk"), and 499-1083 ("very high risk"). The increased risk associated with low eGFR and high ACR persisted in adjusted analyses, examinations of cause-specific hospitalizations, and when CKD was staged by eGFRcys or eGFRcr-cys, a combined equation based on both creatinine and cystatin C. In comparison to eGFRcr, staging by eGFRcys increased the prevalence of CKD to 50%, but hospitalization risks remained similarly high.

DISCUSSION/CONCLUSION

In older adults, decreased eGFR, increased ACR, and KDIGO risk stages based on a combination of these measures, were strong risk factors for hospitalization. These relationships were consistent, regardless of the marker used to estimate GFR, but the use of cystatin C resulted in a substantially higher prevalence of CKD than the use of creatinine. Older adults in the population with very high risk stages of CKD have hospitalization rates exceeding 500 per 1,000 person-years.

Evaluating Glomerular Filtration Rate Slope as a Surrogate End Point for ESKD in Clinical Trials: An Individual Participant Meta-Analysis of Observational Data

BACKGROUND

Decline in eGFR is a biologically plausible surrogate end point for the progression of CKD in clinical trials. However, it must first be tested to ensure strong associations with clinical outcomes in diverse populations, including patients with higher eGFR.

METHODS

To investigate the association between 1-, 2-, and 3-year changes in eGFR (slope) with clinical outcomes over the long term, we conducted a random effects meta-analysis of 3,758,551 participants with baseline eGFR≥60 ml/min per 1.73 m² and 122,664 participants with eGFR<60 ml/min per 1.73 m² from 14 cohorts followed for an average of 4.2 years.

RESULTS

Slower eGFR decline by 0.75 ml/min per 1.73 m² per year over 2 years was associated with lower risk of ESKD in participants with baseline eGFR≥60 ml/min per 1.73 m² (adjusted hazard ratio, 0.70; 95% CI, 0.68 to 0.72) and eGFR<60 ml/min per 1.73 m² (0.71; 95% CI, 0.68 to 0.74). The relationship was stronger with 3-year slope. For a rapidly progressing population with predicted 5-year risk of ESKD of 8.3%, an intervention that reduced eGFR decline by 0.75 ml/min per 1.73 m² per year over 2 years would reduce the ESKD risk by 1.6%. For a hypothetical low-risk population with a predicted 5-year ESKD risk of 0.58%, the same intervention would reduce the risk by only 0.13%.

CONCLUSIONS

Slower decline in eGFR was associated with lower risk of subsequent ESKD, even in participants with eGFR≥60 ml/min per 1.73 m², but those with the highest risk would be expected to benefit the most.

Plant-Based Diets and Incident CKD and Kidney Function

BACKGROUND AND OBJECTIVES

The association between plant-based diets, incident CKD, and kidney function decline has not been examined in the general population. We prospectively investigated this relationship in a population-based study, and evaluated if risk varied by different types of plant-based diets.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Analyses were conducted in a sample of 14,686 middle-aged adults enrolled in the Atherosclerosis Risk in Communities study. Diets were characterized using four plant-based diet indices. In the overall plant-based diet index, all plant foods were positively scored; in the healthy plant-based diet index, only healthful plant foods were positively scored; in the provegetarian diet, selected plant foods were positively scored. In the less healthy plant-based diet index, only less healthful plant foods were positively scored. All indices negatively scored animal foods. We used Cox proportional hazards models to study the association with incident CKD and linear mixed models to examine decline in eGFR, adjusting for confounders.

RESULTS

During a median follow-up of 24 years, 4343 incident CKD cases occurred. Higher adherence to a healthy plant-based diet (HR comparing quintile 5 versus quintile 1 [HRQ5 versus Q1], 0.86; 95% confidence interval [95% CI], 0.78 to 0.96; P for trend =0.001) and a provegetarian diet (HRQ5 versus Q1, 0.90; 95% CI, 0.82 to 0.99; P for trend =0.03) were associated with a lower risk of CKD, whereas higher adherence to a less healthy plant-based diet (HRQ5 versus Q1, 1.11; 95% CI, 1.01 to 1.21; P for trend =0.04) was associated with an elevated risk. Higher adherence to an overall plant-based diet and a healthy plant-based diet was associated with slower eGFR decline. The proportion of CKD attributable to lower adherence to healthy plant-based diets was 4.1% (95% CI, 0.6% to 8.3%).

CONCLUSIONS

Higher adherence to healthy plant-based diets and a vegetarian diet was associated with favorable kidney disease outcomes.