A cohort study of sodium-glucose cotransporter-2 inhibitors after acute kidney injury among Veterans with diabetic kidney disease.

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) reduce the risk for several adverse outcomes among patients with diabetic kidney disease. Yet, optimal timing for SGLT2i after acute kidney injury (AKI) is uncertain, as are the providers responsible for post-AKI SGLT2i initiation. Using a retrospective cohort of United States Veterans with diabetes mellitus type 2 and proteinuria, we examined encounters by provider specialty before SGLT2i initiation and subsequent all-cause mortality after hospitalization with AKI, defined by a 50% or more rise in serum creatinine. Covariates included recovery, defined by return to a 110% or less of baseline creatinine, and time since AKI hospitalization. Among 21,330 eligible Veterans, 7,798 died (37%) and 6,562 received a SGLT2i (31%) over median follow-up of 2.1 years. Post-AKI SGLT2i use was associated with lower mortality risk [adjusted hazard ratio 0.63 (95% confidence interval 0.58-0.68)]. Compared with neither SGLT2i use nor recovery, mortality risk was similar with recovery without SGLT2i use [0.97 (0.91-1.02)] but was lower without recovery prior to SGLT2i use [0.62 (0.55-0.71)] and with SGLT2i use after recovery [0.60 (0.54-0.67)]. Finally, the effect of SGLT2i was stable over time (P for time-interaction 0.19). Thus, we observed reduced mortality with SGLT2i use after AKI among Veterans with diabetic kidney disease whether started earlier or later or before or after observed recovery. Hence, patients with diabetic kidney disease who receive a SGLT2i earlier after AKI experience no significant harm impacting mortality and experience a lower mortality risk than those who do not.

Vaccine Effectiveness Against SARS-CoV-2 Related Hospitalizations in People who had Experienced Homelessness or Incarceration - Findings from the Minnesota EHR Consortium.

COVID-19 disproportionately affects people experiencing homelessness or incarceration. While homelessness or incarceration alone may not impact vaccine effectiveness, medical comorbidities along with social conditions associated with homelessness or incarceration may impact estimated vaccine effectiveness. COVID-19 vaccines reduce rates of hospitalization and death; vaccine effectiveness (VE) against severe outcomes in people experiencing homelessness or incarceration is unknown. We conducted a retrospective, observational cohort study evaluating COVID-19 vaccine VE against SARS-CoV-2 related hospitalization (positive SARS-CoV-2 molecular test same week or within 3 weeks prior to hospital admission) among patients who had experienced homelessness or incarceration. We utilized data from 8 health systems in the Minnesota Electronic Health Record Consortium linked to data from Minnesota's immunization information system, Homeless Management Information System, and Department of Corrections. We included patients 18 years and older with a history of experiencing homelessness or incarceration. VE and 95% Confidence Intervals (CI) against SARS-CoV-2 hospitalization were estimated for primary series and one booster dose from Cox proportional hazard models as 100*(1-Hazard Ratio) during August 26, 2021, through October 8, 2022 adjusting for patient age, sex, comorbid medical conditions, and race/ethnicity. We included 80,051 individuals who had experienced homelessness or incarceration. Adjusted VE was 52% (95% CI, 41-60%) among those 22 weeks or more since their primary series, 66% (95% CI, 53-75%) among those less than 22 weeks since their primary series, and 69% (95% CI: 60-76%) among those with one booster. VE estimates were consistently lower during the Omicron predominance period compared with the combined Omicron and Delta periods. Despite higher exposure risk, COVID-19 vaccines provided good effectiveness against SARS-CoV-2 related hospitalizations in persons who have experienced homelessness or incarceration.

Risk for Chronic Kidney Disease Progression After Acute Kidney Injury: Findings From the Chronic Renal Insufficiency Cohort Study.

BACKGROUND: Prior studies associating acute kidney injury (AKI) with more rapid subsequent loss of kidney function had methodological limitations, including inadequate control for differences between patients who had AKI and those who did not. OBJECTIVE: To determine whether AKI is independently associated with subsequent kidney function trajectory among patients with chronic kidney disease (CKD). DESIGN: Multicenter prospective cohort study. SETTING: United States. PARTICIPANTS: Patients with CKD (n = 3150). MEASUREMENTS: Hospitalized AKI was defined by a 50% or greater increase in inpatient serum creatinine (SCr) level from nadir to peak. Kidney function trajectory was assessed using estimated glomerular filtration rate (eGFR) based on SCr level (eGFRcr) or cystatin C level (eGFRcys) measured at annual study visits. RESULTS: During a median follow-up of 3.9 years, 433 participants had at least 1 AKI episode. Most episodes (92%) had stage 1 or 2 severity. There were decreases in eGFRcr (-2.30 [95% CI, -3.70 to -0.86] mL/min/1.73 m2) and eGFRcys (-3.61 [CI, -6.39 to -0.82] mL/min/1.73 m2) after AKI. However, in fully adjusted models, the decreases were attenuated to -0.38 (CI, -1.35 to 0.59) mL/min/1.73 m2 for eGFRcr and -0.15 (CI, -2.16 to 1.86) mL/min/1.73 m2 for eGFRcys, and the CI bounds included the possibility of no effect. Estimates of changes in eGFR slope after AKI determined by either SCr level (0.04 [CI, -0.30 to 0.38] mL/min/1.73 m2 per year) or cystatin C level (-0.56 [CI, -1.28 to 0.17] mL/min/1.73 m2 per year) also had CI bounds that included the possibility of no effect. LIMITATIONS: Few cases of severe AKI, no adjudication of AKI cause, and lack of information about nephrotoxic exposures after hospital discharge. CONCLUSION: After pre-AKI eGFR, proteinuria, and other covariables were accounted for, the association between mild to moderate AKI and worsening subsequent kidney function in patients with CKD was small. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Renin-Angiotensin-Aldosterone System Blockade after AKI with or without Recovery among US Veterans with Diabetic Kidney Disease.

SIGNIFICANCE STATEMENT: Among patients with CKD, optimal use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers after AKI is uncertain. Despite these medications' ability to reduce risk of mortality and other adverse outcomes, there is concern that ACEi/ARB use may delay recovery of kidney function or precipitate recurrent AKI. Prior studies have provided conflicting data regarding the optimal timing of these medications after AKI and have not addressed the role of kidney recovery in determining appropriate timing. This study in US Veterans with diabetes mellitus and proteinuria demonstrated an association between ACEi/ARB use and lower mortality. This association was more pronounced with earlier post-AKI ACEi/ARB use and was not meaningfully affected by initiating ACEis/ARBs before versus after recovery from AKI. BACKGROUND: Optimal use of angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) after AKI is uncertain. METHODS: Using data derived from electronic medical records, we sought to estimate the association between ACEi/ARB use after AKI and mortality in US military Veterans with indications for such treatment (diabetes and proteinuria) while accounting for AKI recovery. We used ACEi/ARB treatment after hospitalization with AKI (defined as serum creatinine ≥50% above baseline concentration) as a time-varying exposure in Cox models. The outcome was all-cause mortality. Recovery was defined as return to ≤110% of baseline creatinine. A secondary analysis focused on ACEi/ARB use relative to AKI recovery (before versus after). RESULTS: Among 54,735 Veterans with AKI, 31,146 deaths occurred over a median follow-up period of 2.3 years. Approximately 57% received an ACEi/ARB <3 months after hospitalization. In multivariate analysis with time-varying recovery, post-AKI ACEi/ARB use was associated with lower risk of mortality (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.72 to 0.77). The association between ACEi/ARB use and mortality varied over time, with lower mortality risk associated with earlier initiation ( P for interaction with time <0.001). In secondary analysis, compared with those with neither recovery nor ACEi/ARB use, risk of mortality was lower in those with recovery without ACEi/ARB use (aHR, 0.90; 95% CI, 0.87 to 0.94), those without recovery with ACEi/ARB use (aHR, 0.69; 95% CI, 0.66 to 0.72), and those with ACEi/ARB use after recovery (aHR, 0.70; 95% CI, 0.67 to 0.73). CONCLUSIONS: This study demonstrated lower mortality associated with ACEi/ARB use in Veterans with diabetes, proteinuria, and AKI, regardless of recovery. Results favored earlier ACEi/ARB initiation.

Protection From COVID-19 mRNA Vaccination and Prior SARS-CoV-2 Infection Against COVID-19-Associated Encounters in Adults During Delta and Omicron Predominance.

BACKGROUND: Data assessing protection conferred from COVID-19 mRNA vaccination and/or prior SARS-CoV-2 infection during Delta and Omicron predominance periods in the United States are limited. METHODS: This cohort study included persons ≥18 years who had ≥1 health care encounter across 4 health systems and had been tested for SARS-CoV-2 before 26 August 2021. COVID-19 mRNA vaccination and prior SARS-CoV-2 infection defined the exposure. Cox regression estimated hazard ratios (HRs) for the Delta and Omicron periods; protection was calculated as (1-HR)×100%. RESULTS: Compared to unvaccinated and previously uninfected persons, during Delta predominance, protection against COVID-19-associated hospitalizations was high for those 2- or 3-dose vaccinated and previously infected, 3-dose vaccinated alone, and prior infection alone (range, 91%-97%, with overlapping 95% confidence intervals [CIs]); during Omicron predominance, estimates were lower (range, 77%-90%). Protection against COVID-19-associated emergency department/urgent care (ED/UC) encounters during Delta predominance was high for those exposure groups (range, 86%-93%); during Omicron predominance, protection remained high for those 3-dose vaccinated with or without a prior infection (76%; 95% CI = 67%-83% and 71%; 95% CI = 67%-73%, respectively). CONCLUSIONS: COVID-19 mRNA vaccination and/or prior SARS-CoV-2 infection provided protection against COVID-19-associated hospitalizations and ED/UC encounters regardless of variant. Staying up-to-date with COVID-19 vaccination still provides protection against severe COVID-19 disease, regardless of prior infection.

Renal denervation: recent developments in clinical and preclinical research.

PURPOSE OF REVIEW: Renal denervation represents a new dimension to hypertension treatment, with multiple device manufacturers seeking premarket FDA approval currently. Interest in the efficacy and safety of the treatment has spurred compelling mechanistic studies into the function of renal nerves and downstream impacts of denervation. RECENT FINDINGS: A trial of the ultrasound Paradise Catheter system (RADIANCE II) found a 6.3 mmHg reduction in SBP relative to sham controls. A trial of the Symplicity Spyral system (SPYRAL HTN-ON MED) found an insignificant reduction in SBP relative to sham controls. Individuals were taking antihypertensive medications during the study, and investigators note the sham group experienced a larger medication burden than the denervated group. Recent preclinical studies have evaluated potential risks of renal denervation, how sympathetic activity broadly is affected, as well as identifying possible biomarkers to identify individuals where denervation would be more successful. SUMMARY: Studies of renal denervation continue to find a robust antihypertensive effect, especially in studies wherein medications are withdrawn. Further investigation into mechanisms and indicators for usage of the technique will be important in identifying the patient population most likely to benefit from usage of renal denervation.

Effectiveness of BNT162b2 and mRNA-1273 Second Doses and Boosters for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection and SARS-CoV-2-Related Hospitalizations: A Statewide Report From the Minnesota Electronic Health Record Consortium.

Using vaccine data combined with electronic health records, we report that mRNA boosters provide greater protection than a 2-dose regimen against SARS-CoV-2 infection and related hospitalizations. The benefit of a booster was more evident in the elderly and those with comorbidities.

KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Blood Pressure in CKD.

The Kidney Disease Outcomes Quality Initiative (KDOQI) convened a work group to review the 2021 KDIGO (Kidney Disease: Improving Global Outcomes) guideline for the management of blood pressure in chronic kidney disease (CKD). This commentary is the product of that work group and presents the recommendations and practice points from the KDIGO guideline in the context of US clinical practice. A critical addition to the KDIGO guideline is the recommendation for accurate assessment of blood pressure using standardized office blood pressure measurement. In the general adult population with CKD, KDIGO recommends a goal systolic blood pressure less than 120 mm Hg on the basis of results from the Systolic Blood Pressure Intervention Trial (SPRINT) and secondary analyses of the Action to Control Cardiovascular Risk in Diabetes-Blood Pressure (ACCORD-BP) trial. The KDOQI work group agreed with most of the recommendations while highlighting the weak evidence base especially for patients with diabetes and advanced CKD.

Kidney-Metabolic Factors Associated with Cognitive Impairment in Chronic Kidney Disease: A Pilot Study.

INTRODUCTION: The associations of kidney-metabolic biomarkers with cognitive impairment (CI) beyond the estimated glomerular filtration rate (eGFR, in mL/min/1.73 m2) and albuminuria levels are not well understood. In exploratory analysis, our objective was to determine the extent that three kidney-metabolic factors, previously proposed as mechanisms of CI and commonly abnormal in chronic kidney disease (CKD), were associated with prevalent CI in CKD participants, adjusted for kidney function measures. METHODS: The study cohort included community-dwelling individuals aged ≥45 years with CKD (eGFR <60), not requiring dialysis, recruited from four health systems. We examined the serum biomarkers bicarbonate (CO2), TNFαR1, and cholesterol as primary exposures. A structured neuropsychological battery conducted by trained staff measured global and domain-specific cognitive performance. Logistic regression analyses estimated the cross-sectional associations between kidney-metabolic measures and global and cognitive domain-specific moderate/severe (Mod/Sev) CI, adjusted for the eGFR, urinary albumin-creatinine ratio (UACR, mg/g), demographics, comorbid conditions, and other kidney-metabolic biomarkers commonly abnormal in CKD. RESULTS: Among 436 CKD participants with mean age 70 years, 16% were Black, the mean eGFR was 34, and the median [IQR] UACR was 49 [0.0, 378] mg/g. In adjusted models, increased TNFαR1 was associated with global Mod/Sev CI (odds ratio [95% confidence interval] = 1.40 [1.02, 1.93]; p = 0.04); low bicarbonate (CO2 <20 mEq/L) with Mod/Sev memory impairment (3.04 [1.09, 8.47]; p = 0.03), and each 10-mg/dL lower cholesterol was associated with Mod/Sev executive function/processing speed impairment (1.12 [1.02, 1.23]; p = 0.02). However, after adjustment for multiple comparisons, these associations were no longer significant nor were any other kidney-metabolic factors significant for any CI classification. CONCLUSION: In exploratory analyses in a CKD population, three kidney-metabolic factors were associated with CI, but after adjustment for multiple comparisons, were no longer significant. Future studies in larger CKD populations are needed to assess these potential risk factors for CI.

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

RATIONALE & OBJECTIVE: Screening for chronic kidney disease (CKD) is recommended for patients with diabetes and hypertension as stated by the respective professional societies. However, CKD, a silent disease usually detected at later stages, is associated with low socioeconomic status (SES). We assessed whether adding census tract SES status to the standard screening approach improves our ability to identify patients with CKD. STUDY DESIGN: Screening test analysis. SETTINGS & PARTICIPANTS: Electronic health records (EHR) of 256,162 patients seen at a health care system in the 7-county Minneapolis/St. Paul area and linked census tract data. EXPOSURE: The first quartile of census tract SES (median value of owner-occupied housing units <$165,200; average household income <$35,935; percentage of residents >25 years of age with a bachelor's degree or higher <20.4%), hypertension, and diabetes. OUTCOMES: CKD (eGFR <60 mL/min/1.73 m2, or urinary albumin-creatinine ratio >30mg/g, or urinary protein-creatinine ratio >150mg/g, or urinary analysis [albuminuria] >30 mg/d). ANALYTICAL APPROACH: Sensitivity, specificity, and number needed to screen (NNS) to detect CKD if we screened patients who had hypertension and/or diabetes and/or who lived in low-SES tracts (belonging to the first quartile of any of the 3 measures of tract SES) versus the standard approach. RESULTS: CKD was prevalent in 13% of our cohort. Sensitivity, specificity, and NNS of detecting CKD after adding tract SES to the screening approach were 67% (95% CI, 66.2%-67.2%), 61% (95% CI, 61.1%-61.5%), and 5, respectively. With the standard approach, sensitivity of detecting CKD was 60% (95% CI, 59.4%-60.4%), specificity was 73% (95% CI, 72.4%-72.7%), and NNS was 4. LIMITATIONS: One health care system and selection bias. CONCLUSIONS: Leveraging patients' addresses from the EHR and adding tract-level SES to the standard screening approach modestly increases the sensitivity of detecting patients with CKD at a cost of decreased specificity. Identifying further factors that improve CKD detection at an early stage are needed to slow the progression of CKD and prevent cardiovascular complications.

Podocyte density is reduced in kidney allografts with high-risk APOL1 genotypes at transplantation.

Variants in apolipoprotein L1 (APOL1) gene are associated with nondiabetic kidney diseases in black subjects and reduced kidney transplant graft survival. Living and deceased black kidney donors (n = 107) were genotyped for APOL1 variants. To determine whether allografts from high-risk APOL1 donors have reduced podocyte densities contributing to allograft failure, we morphometrically estimated podocyte number, glomerular volume, and podocyte density. We compared allograft loss and eGFR trajectories stratified by APOL1 high-risk and low-risk genotypes. Demographic characteristics were similar in high-risk (n = 16) and low-risk (n = 91) donors. Podocyte density was significantly lower in high-risk than low-risk donors (108 ± 26 vs 127 ± 40 podocytes/106 um3 , P = .03). Kaplan-Meier graft survival (high-risk 61% vs. low-risk 91%, p-value = 0.049) and multivariable Cox models (hazard ratio = 2.6; 95% CI, 0.9-7.8) revealed higher graft loss in recipients of APOL1 high-risk allografts over 48 months. More rapid eGFR decline was seen in recipients of high-risk APOL1 allografts (P < .001). At 60 months, eGFR was 27 vs. 51 mL/min/1.73 min2 in recipients of APOL1 high-risk vs low-risk kidney allografts, respectively. Kidneys from high-risk APOL1 donors had worse outcomes versus low-risk APOL1 genotypes. Lower podocyte density in kidneys from high-risk APOL1 donors may increase susceptibility to CKD from subsequent stresses in both the recipients and donors.

Prognostic Significance of Ambulatory BP Monitoring in CKD: A Report from the Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND: Whether ambulatory BP monitoring is of value in evaluating risk for outcomes in patients with CKD is not clear. METHODS: We followed 1502 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study for a mean of 6.72 years. We evaluated, as exposures, ambulatory BP monitoring profiles (masked uncontrolled hypertension, white-coat effect, sustained hypertension, and controlled BP), mean ambulatory BP monitoring and clinic BPs, and diurnal variation in BP-reverse dipper (higher at nighttime), nondipper, and dipper (lower at nighttime). Outcomes included cardiovascular disease (a composite of myocardial infarction, cerebrovascular accident, heart failure, and peripheral arterial disease), kidney disease (a composite of ESKD or halving of the eGFR), and mortality. RESULTS: Compared with having controlled BP, the presence of masked uncontrolled hypertension independently associated with higher risk of the cardiovascular outcome and the kidney outcome, but not with all-cause mortality. Higher mean 24-hour systolic BP associated with higher risk of cardiovascular outcome, kidney outcome, and mortality, independent of clinic BP. Participants with the reverse-dipper profile of diurnal BP variation were at higher risk of the kidney outcome. CONCLUSIONS: In this cohort of participants with CKD, BP metrics derived from ambulatory BP monitoring are associated with cardiovascular outcomes, kidney outcomes, and mortality, independent of clinic BP. Masked uncontrolled hypertension and mean 24-hour BP associated with high risk of cardiovascular disease and progression of kidney disease. Alterations of diurnal variation in BP are associated with high risk of progression of kidney disease, stroke, and peripheral arterial disease. These data support the wider use of ambulatory BP monitoring in the evaluation of hypertension in patients with CKD. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/JASN/2020_09_24_JASN2020030236.mp3.

Acute Kidney Injury following Enhanced Recovery after Surgery in Patients Undergoing Radical Cystectomy.

PURPOSE: We assessed the effect of enhanced recovery after surgery protocol related fluid restriction on kidney function and the incidence of postoperative acute kidney injury and 3-month kidney function. MATERIALS AND METHODS: In a retrospectively collected, single institution cohort we studied 296 consecutive patients (146 pre-enhanced recovery after surgery vs 150 enhanced recovery after surgery) who underwent radical cystectomy from 2010 to 2018. The primary outcome was the incidence of postoperative acute kidney injury. Secondary outcomes were length of hospital stay, time to bowel movements, time to tolerate regular diet, postoperative complications and 30-day readmission rate. Study limitations include its retrospective design and relatively modest sample size. RESULTS: We observed an increased rate of postoperative acute kidney injury in patients on the enhanced recovery after surgery protocol (42.7% vs 30.1%, OR 1.725, p=0.025). On multivariate analysis enhanced recovery after surgery protocol remained a significant predictor of acute kidney injury even when controlling for other covariates including baseline kidney function (OR 1.8, 95% CI 1.04-3.30, p=0.036). Patients with postoperative acute kidney injury demonstrated significantly higher odds of stage 3 chronic kidney disease at 3 months even after controlling for baseline renal function (OR 2.5, 95% CI 1.3-4.9, p=0.016). CONCLUSIONS: Use of an enhanced recovery after surgery protocol following radical cystectomy was associated with a higher risk of postoperative acute kidney injury in patients who had baseline chronic kidney disease which could be related to the restricted perioperative fluid management mandated by enhanced recovery after surgery. Use of the enhanced recovery after surgery protocol did not impact the length of hospital stay or readmission rates.

Blood Pressure Measurement: A KDOQI Perspective.

The majority of patients with chronic kidney disease (CKD) have elevated blood pressure (BP). In patients with CKD, hypertension is associated with increased risk for cardiovascular disease, progression of CKD, and all-cause mortality. New guidelines from the American College of Cardiology/American Heart Association (ACC/AHA) recommend new thresholds and targets for the diagnosis and treatment of hypertension in patients with and without CKD. A new aspect of the guidelines is the recommendation for measurement of out-of-office BP to confirm the diagnosis of hypertension and guide therapy. In this KDOQI (Kidney Disease Outcomes Quality Initiative) perspective, we review the recommendations for accurate BP measurement in the office, at home, and with ambulatory BP monitoring. Regardless of location, validated devices and appropriate cuff sizes should be used. In the clinic and at home, proper patient preparation and positioning are critical. Patients should receive information about the importance of BP measurement techniques and be encouraged to advocate for adherence to guideline recommendations. Implementing appropriate BP measurement in routine practice is feasible and should be incorporated in system-wide efforts to improve the care of patients with hypertension. Hypertension is the number 1 chronic disease risk factor in the world; BP measurements in the office, at home, and with ambulatory BP monitoring should adhere to recommendations from the AHA.

Tubular Biomarkers and Chronic Kidney Disease Progression in SPRINT Participants.

BACKGROUND: Kidney tubular atrophy on biopsy is a strong predictor of chronic kidney disease (CKD) progression, but tubular health is poorly quantified by traditional measures including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of impaired tubule function would be associated with faster eGFR declines in persons with CKD. METHODS: We measured baseline urine concentrations of uromodulin, ß2-microglobulin (ß2m), and α1-microglobulin (α1m) among 2,428 participants of the Systolic Blood Pressure Intervention Trial with an eGFR <60 mL/min/1.73 m2. We used linear mixed models to evaluate biomarker associations with annualized relative change in eGFR, stratified by randomization arm. RESULTS: At baseline, the mean age was 73 ± 9 years and eGFR was 46 ± 11 mL/min/1.73 m2. In the standard blood pressure treatment arm, each 2-fold higher urinary uromodulin was associated with slower % annual eGFR decline (0.34 [95% CI: 0.08, 0.60]), whereas higher urinary ß2m was associated with faster % annual eGFR decline (-0.10 [95% CI: -0.18, -0.02]) in multivariable-adjusted models including baseline eGFR and albuminuria. Associations were weaker and did not reach statistical significance in the intensive blood pressure treatment arm for either uromodulin (0.11 [-0.13, 0.35], p value for interaction by treatment arm = 0.045) or ß2m (-0.01 [-0.08, 0.08], p value for interaction = 0.001). Urinary α1m was not independently associated with eGFR decline in the standard (0.01 [-0.22, 0.23]) or intensive (0.03 [-0.20, 0.25]) arm. CONCLUSIONS: Among trial participants with hypertension and CKD, baseline measures of tubular function were associated with subsequent declines in kidney function, although these associations were diminished by intensive blood pressure control.

Trends in Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Use among Those with Impaired Kidney Function in the United States.

BACKGROUND: Although hypertension is common in CKD and evidence-based treatment of hypertension has changed considerably, contemporary and nationally representative information about use of angiotensin-converting enzyme (ACEs) inhibitors or angiotensin II receptor blockers (ARBs) in CKD is lacking. METHODS: We examined ACE/ARB trends from 1999 to 2014 among 38,885 adult National Health and Nutrition Examination Survey participants with creatinine-based eGFR<60 ml/min per 1.73 m2 or urinary albumin-to-creatinine ratio ≥30 mg/g. RESULTS: Of 7085 participants with CKD, 34.9% used an ACE/ARB. Across four eras studied, rates of use rose significantly (rates were 25.5% in 1999-2002, 33.3% in 2003-2006, 39.0% in 2007-2010, and 40.1% in 2011-2014) but appeared to plateau after 2003. Among those with CKD, use was significantly greater among non-Hispanic white and black individuals (36.1% and 38.2%, respectively) and lower among Hispanic individuals (26.7%) and other races/ethnicities (29.3%). In age-, sex-, and race/ethnicity-adjusted models, ACE/ARB use was significantly associated with era (adjusted odds ratios [aOR], 1.41; 95% confidence interval [95% CI], 1.14 to 1.74 for 2003-2006, 1.84; 95% CI, 1.48 to 2.28 for 2007-2010, and 2.02; 95% CI, 1.61 to 2.53 for 2011-2014 versus 1999-2002); it also was significantly associated with non-Hispanic black versus non-Hispanic white race/ethnicity (aOR, 1.40; 95% CI, 1.19 to 1.66). Other multivariate associations included older age, men, elevated BMI, diabetes mellitus, treated hypertension, cardiac failure, myocardial infarction, health insurance, and receiving medical care within the prior year. CONCLUSIONS: Rates of ACE/ARB use increased in the early 2000s among United States adults with CKD, but for unclear reasons, use appeared to plateau in the ensuing decade. Research examining barriers to care and other factors is needed.

Urinary Biomarkers of Tubular Damage Are Associated with Mortality but Not Cardiovascular Risk among Systolic Blood Pressure Intervention Trial Participants with Chronic Kidney Disease.

BACKGROUND: Kidney tubulointerstitial fibrosis on biopsy is a strong predictor of chronic kidney disease (CKD) progression, and CKD is associated with elevated risk of cardiovascular disease (CVD). Tubular health is poorly quantified by traditional kidney function measures, including estimated glomerular filtration rate (eGFR) and albuminuria. We hypothesized that urinary biomarkers of tubular injury, inflammation, and repair would be associated with higher risk of CVD and mortality in persons with CKD. METHODS: We measured urinary concentrations of interleukin-18 (IL-18), kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and chitinase-3-like protein-1 (YKL-40) at baseline among 2,377 participants of the Systolic Blood Pressure Intervention Trial who had an eGFR < 60 mL/min/1.73 m2. We used Cox proportional hazards models to evaluate biomarker associations with CVD events and all-cause mortality. RESULTS: At baseline, the mean age of participants was 72 ± 9 years, and eGFR was 48 ± 11 mL/min/1.73 m2. Over a median follow-up of 3.8 years, 305 CVD events (3.6% per year) and 233 all-cause deaths (2.6% per year) occurred. After multivariable adjustment including eGFR, albuminuria, and urinary creatinine, none of the biomarkers showed statistically significant associations with CVD risk. Urinary IL-18 (hazard ratio [HR] per 2-fold higher value, 1.14; 95% CI 1.01-1.29) and YKL-40 (HR per 2-fold higher value, 1.08; 95% CI 1.02-1.14) concentrations were each incrementally associated with higher mortality risk. Associations were similar when stratified by randomized blood pressure arm. CONCLUSIONS: Among hypertensive trial participants with CKD, higher urinary IL-18 and YKL-40 were associated with higher risk of mortality, but not CVD.

The impact of outpatient acute kidney injury on mortality and chronic kidney disease: a retrospective cohort study.

BACKGROUND: Acute kidney injury (AKI) has been extensively studied in hospital settings. Limited data exist regarding outcomes for patients with outpatient AKI who are not subsequently admitted. We investigated whether outpatient AKI, defined by a 50% increase in creatinine (Cr), is associated with increased mortality and renal events. METHODS: In this retrospective study, outpatient serum Cr values from adults receiving primary care at a health system during an 18-month exposure period were used to categorize patients into one of five groups (no outpatient AKI, outpatient AKI with recovery, outpatient AKI without recovery, outpatient AKI without repeat Cr and no Cr). Principal outcomes of all-cause mortality and renal events (50% decline in estimated glomerular filtration rate to <30 mL/min/1.73 m2) were examined using Cox proportional hazards models. RESULTS: Among 384 869 eligible patients, 51% had at least one Cr measured during the exposure period. Outpatient AKI occurred in 1.4% of patients while hospital AKI occurred in only 0.3% of patients. The average follow-up was 5.3 years. Outpatient AKI was associated with an increased risk of all-cause mortality {adjusted hazard ratio [aHR] 1.90 [95% confidence interval (CI) 1.76-2.06]} and results were consistent across all AKI groups. Outpatient AKI was also associated with an increased risk of renal events [aHR 1.33 (95% CI 1.11-1.59)], even among those who recovered. CONCLUSIONS: Outpatient AKI is more prevalent than inpatient AKI and is a risk factor for all-cause mortality and renal events, even among those who recover kidney function. Further research is necessary to determine risk factors and identify strategies for preventing outpatient AKI.

Kidney Damage Biomarkers and Incident Chronic Kidney Disease During Blood Pressure Reduction: A Case-Control Study.

Background: Whether the increased incidence of chronic kidney disease (CKD) during intensive systolic blood pressure (SBP) lowering is accompanied by intrinsic kidney injury is unknown. Objective: To compare changes in kidney damage biomarkers between incident CKD case participants and matched control participants as well as between case participants in the intensive (<120 mm Hg) versus the standard (<140 mm Hg) SBP management groups of SPRINT (Systolic Blood Pressure Intervention Trial). Design: Nested case-control study within SPRINT. Setting: Adults with hypertension without baseline kidney disease. Participants: Case participants (n = 162), who developed incident CKD during trial follow-up (128 in the intensive and 34 in the standard group), and control participants (n = 162) without incident CKD, who were matched on age, sex, race, baseline estimated glomerular filtration rate, and randomization group. Measurements: 9 urinary biomarkers of kidney damage were measured at baseline and at 1 year. Linear mixed-effects models were used to estimate 1-year biomarker changes. Results: Higher concentrations of urinary albumin, kidney injury molecule-1, and monocyte chemoattractant protein-1 at baseline were significantly associated with greater odds of incident CKD (adjusted odds ratio per doubling: 1.50 [95% CI, 1.14 to 1.98], 1.51 [CI, 1.05 to 2.17], and 1.70 [CI, 1.13 to 2.56], respectively). After 1 year of blood pressure intervention, incident CKD case participants in the intensive group had significantly greater decreases in albumin-creatinine ratio (ACR), interleukin-18, anti-chitinase-3-like protein 1 (YKL-40), and uromodulin than the matched control participants. Compared with case participants in the standard group, those in the intensive group had significantly greater decreases in ACR, ß2-microglobulin, α1-microglobulin, YKL-40, and uromodulin. Limitation: Biomarker measurements were available only at baseline and 1 year. Conclusion: Incident CKD in the setting of intensive SBP lowering was accompanied by decreases, rather than elevations, in levels of kidney damage biomarkers and thus may reflect benign changes in renal blood flow rather than intrinsic injury. Primary Funding Source: National Institute for Diabetes and Digestive and Kidney Diseases.

Masked Hypertension in CKD: Increased Prevalence and Risk for Cardiovascular and Renal Events.

PURPOSE OF REVIEW: Hypertension and chronic kidney disease (CKD) are inextricably linked. The causal nature of the relationship is bidirectional. This relationship holds when blood pressure is assessed in the clinic and outside the clinic with home and ambulatory blood pressure monitoring. Patients with CKD are more likely to have high-risk hypertension phenotypes, such as masked and sustained hypertension, and are at increased risk for cardiovascular disease. The purpose of this review is to describe the increased prevalence of masked hypertension in patients with CKD and then describe the increased risk for target organ damage and adverse clinical events associated with masked hypertension in patients with CKD. RECENT FINDINGS: The prevalence of masked hypertension is greater in patients with CKD than that of the general population. Recent studies have demonstrated that masked hypertension is associated with increased risk for target organ damage including left ventricular hypertrophy, elevated pulse wave velocity, proteinuria, and decreased estimated glomerular filtration rate in patients with CKD. Additionally, in patients with CKD, masked hypertension is associated with increased risk for cardiovascular disease, end-stage renal disease, and all-cause mortality. Patients with CKD are at increased risk for masked hypertension. Masked hypertension is associated with increased risk for target organ damage and adverse cardiovascular and renal outcomes in patients with CKD. Further research is necessary to better understand the pathophysiology of masked hypertension, the optimal method for diagnosing masked hypertension, and to determine whether masked hypertension is a modifiable risk factor.