Effect of Vitamin D Supplementation on Kidney Function in Adults with Prediabetes: A Secondary Analysis of a Randomized Trial.

BACKGROUND AND OBJECTIVES: Low serum 25-hydroxyvitamin D (25[OH]D) concentration has been associated with higher levels of proteinuria and lower levels of eGFR in observational studies. In the Vitamin D and Type 2 Diabetes (D2d) study, we investigated the effect of vitamin D supplementation on kidney outcomes in a population with prediabetes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Overweight/obese adults with high risk for type 2 diabetes (defined by meeting two of three glycemic criteria for prediabetes) were randomized to vitamin D3 4000 IU per day versus placebo. Median duration of treatment was 2.9 years (interquartile range 2.0-3.5 years). Kidney outcomes included (1) worsening in Kidney Disease: Improving Global Outcomes (KDIGO ) risk score (low, moderate, high, very high) on two consecutive follow-up visits after the baseline visit and (2) mean changes in eGFR and urine albumin-to-creatinine ratio (UACR). RESULTS: Among 2166 participants (mean age 60 years, body mass index 32 kg/m2, serum 25(OH)D 28 ng/ml, eGFR 87 ml/min per 1.73 m2, UACR 11 mg/g, 79% with hypertension), 10% had moderate, high, or very high KDIGO risk score. Over a median follow-up of 2.9 years, there were 28 cases of KDIGO worsening in the vitamin D group and 30 in the placebo group (hazard ratio, 0.89; 95% confidence interval [95% CI], 0.52 to 1.52]). Mean difference in eGFR from baseline was -1.0 ml/min per 1.73 m2 (95% CI, -1.3 to -0.7) in the vitamin D group and -0.1 ml/min per 1.73 m2 (95% CI, -0.4 to 0.2) in the placebo group; between-group difference was -1.0 ml/min per 1.73 m2 (95% CI, -1.4 to -0.6). Mean difference in UACR was 2.7 mg/g (95% CI, 1.2 to 4.3) in the vitamin D group and 2.0 (95% CI, 0.5 to 3.6) in the placebo group; between-group difference was 0.7 mg/g (95% CI, -1.5 to 2.9). CONCLUSIONS: Among persons with prediabetes, who were not preselected on the basis of serum 25(OH)D concentration, vitamin D supplementation did not affect progression of KDIGO risk scores and did not have a meaningful effect on change in UACR or eGFR.

Executive summary of the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease for patients not receiving dialysis represents an update to the KDIGO 2012 guideline on this topic. Development of this guideline update followed a rigorous process of evidence review and appraisal. Guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence. The strength of recommendations is based on the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The scope includes topics covered in the original guideline, such as optimal blood pressure targets, lifestyle interventions, antihypertensive medications, and specific management in kidney transplant recipients and children. Some aspects of general and cardiovascular health, such as lipid and smoking management, are excluded. This guideline also introduces a chapter dedicated to proper blood pressure measurement since all large randomized trials targeting blood pressure with pivotal outcomes used standardized preparation and measurement protocols adhered to by patients and clinicians. Based on previous and new evidence, in particular the Systolic Blood Pressure Intervention Trial (SPRINT) results, we propose a systolic blood pressure target of less than 120 mm Hg using standardized office reading for most people with chronic kidney disease (CKD) not receiving dialysis, the exception being children and kidney transplant recipients. The goal of this guideline is to provide clinicians and patients a useful resource with actionable recommendations supplemented with practice points. The burden of the recommendations on patients and resources, public policy implications, and limitations of the evidence are taken into consideration. Lastly, knowledge gaps and recommendations for future research are provided.

Executive summary of the KDIGO 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease.

The Kidney Disease: Improving Global Outcomes (KDIGO) 2021 Clinical Practice Guideline for the Management of Blood Pressure in Chronic Kidney Disease for patients not receiving dialysis represents an update to the KDIGO 2012 guideline on this topic. Development of this guideline update followed a rigorous process of evidence review and appraisal. Guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence. The strength of recommendations is based on the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) approach. The scope includes topics covered in the original guideline, such as optimal blood pressure targets, lifestyle interventions, antihypertensive medications, and specific management in kidney transplant recipients and children. Some aspects of general and cardiovascular health, such as lipid and smoking management, are excluded. This guideline also introduces a chapter dedicated to proper blood pressure measurement since all large randomized trials targeting blood pressure with pivotal outcomes used standardized preparation and measurement protocols adhered to by patients and clinicians. Based on previous and new evidence, in particular the Systolic Blood Pressure Intervention Trial (SPRINT) results, we propose a systolic blood pressure target of less than 120 mm Hg using standardized office reading for most people with chronic kidney disease (CKD) not receiving dialysis, the exception being children and kidney transplant recipients. The goal of this guideline is to provide clinicians and patients a useful resource with actionable recommendations supplemented with practice points. The burden of the recommendations on patients and resources, public policy implications, and limitations of the evidence are taken into consideration. Lastly, knowledge gaps and recommendations for future research are provided.

Sodium glucose cotransporter 2 inhibitors as diuretic adjuvants in acute decompensated heart failure: a case series.

AIMS: Diuretic resistance is common in acute decompensated heart failure (ADHF). When loop diuretic monotherapy is ineffective, thiazides are often recommended as adjunctive therapy, but these agents have many side effects and are associated with worsened survival. In contrast, sodium glucose cotransporter 2 inhibitors (SGLT-2i's), initially developed as glucose-lowering medications for type 2 diabetes, improve heart failure outcomes. A candidate contributory mechanism for this benefit is their diuretic effects. We sought to describe the safety and efficacy of SGLT-2i's as loop diuretic adjuvants in ADHF. METHODS AND RESULTS: We retrospectively analysed patients who received adjuvant SGLT-2i therapy between August 2016 and June 2018 at Yale-New Haven Hospital. Thirty-one patients comprised the cohort, 58% of whom had type 2 diabetes. Compared with the 24 h prior to SGLT-2i initiation, average weight loss improved (1.0 ± 2.2 kg, P = 0.03 at Day 1; 1.7 ± 4.9 kg, P = 0.08 at Day 2; and 2.1 ± 5.6 kg, P = 0.06 at Day 3), as did urine output (3.7 ± 2.0 L, P = 0.002 at Day 1; 3.4 ± 1.7 L, P = 0.02 at Day 2; and 3.1 ± 1.7 L, P = 0.02 at Day 3) while loop diuretic dosing remaining stable. Creatinine remained unchanged during the 3 days after initiation, as did blood pressure and the incidence of hypokalaemia (P = NS for all). CONCLUSIONS: In this cohort of patients with ADHF, SGLT-2i's improved weight loss, urine output, and diuretic efficiency without worsening of creatinine, potassium, or blood pressure. Further study of SGLT-2i's as a loop diuretic adjuvant is warranted.

Impact of Race on the Association of Mineral Metabolism With Heart Failure: the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Alterations in mineral metabolism, such as high phosphorus, high parathyroid hormone (PTH), and high fibroblast growth factor-23 (FGF-23) have been identified as potential risk factors for heart failure (HF). Important differences in the prevalence of mineral metabolism abnormalities and in the risk of HF have been reported across race and/or ethnic groups. In this study, we evaluated whether the associations of mineral metabolism markers with HF differed by race and/or ethnicity. METHODS: We included participants free of cardiovascular disease from the Multi-Ethnic Study of Atherosclerosis to quantify rates of HF overall and across race and/or ethnic groups. Using Cox models, we tested associations of baseline higher phosphorus (>4 mg/dL), PTH greater than 65 pg/mL, and FGF-23 greater than 46.5 pg/mL with incident HF, and for interactions by race and/or ethnicity, adjusting for sociodemographic and cardiovascular risk factors. RESULTS: Among the 6413 participants, median follow-up time was 14.9 years. The incidence rate for HF was highest for African Americans and lowest for Chinese (4.71 and 2.42 per 1000 person-years, respectively). The prevalence of elevated PTH (18.8% vs 7.4%) but not FGF-23 (23.1% vs 28.8%) was higher in African Americans vs Whites. In multivariable models, the associations of elevated PTH (hazard ratio [HR] 1.50, 95% CI: 1.13-1.99) and FGF-23 (HR 1.37, 95% CI: 1.07-1.75) with incident HF were statistically significant. However, the interactions by race and/or ethnicity were not statistically significant. CONCLUSIONS: In a multiethnic population, higher PTH and FGF-23 were associated with risk of HF in African American and Hispanic individuals. There is no evidence that race and/or ethnicity modifies the association of altered mineral metabolism with risk of HF.

Oral Anticoagulants to Prevent Stroke in Nonvalvular Atrial Fibrillation in Patients With CKD Stage 5D: An NKF-KDOQI Controversies Report.

Stroke risk may be more than 3-fold higher among patients with chronic kidney disease stage 5D (CKD-5D) compared to the general population, with the highest stroke rates noted among those 85 years and older. Atrial fibrillation (AF), a strong risk factor for stroke, is the most common arrhythmia and affects >7% of the population with CKD-5D. Warfarin use is widely acknowledged as an important intervention for stroke prevention with nonvalvular AF in the general population. However, use of oral anticoagulants for stroke prevention in patients with CKD-5D and nonvalvular AF continues to be debated by the nephrology community. In this National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) controversies report, we discuss the existing observational studies that examine warfarin use and associated stroke and bleeding risks in adults with CKD-5D and AF. Non-vitamin K-dependent oral anticoagulants and their potential use for stroke prevention in patients with CKD-5D and nonvalvular AF are also discussed. Data from randomized clinical trials are urgently needed to determine the benefits and risks of oral anticoagulant use for stroke prevention in the setting of AF among patients with CKD-5D.

Early and late effects of high- versus low-dose angiotensin receptor blockade on renal function and outcomes in patients with chronic heart failure.

OBJECTIVES: This study investigated the dose-related effect of losartan on changes in renal function using data from the HEAAL (Heart failure Endpoint evaluation of Angiotensin II Antagonist Losartan) trial. BACKGROUND: Angiotensin receptor blockers adversely affect renal function in patients with heart failure (HF). The time course and dose dependency of this time course, as well as the clinical implications of these changes in renal function, are not well described. METHODS: Subjects in the HEAAL dataset (n = 3,843) were studied. Changes in estimated glomerular filtration rate (eGFR) over time were compared between dose groups. The association between the timing of incident increases in serum creatinine (SCr) >0.3 mg/dl and clinical outcomes was explored. RESULTS: Compared with 50 mg, 150 mg losartan led to a greater reduction in eGFR across time (mean difference:-3.76 ml/min/1.73 m(2); p < 0.0001). This difference was driven by early changes, and differences in eGFRafter 4 months were not significant (mean difference: 0.42 ml/min/1.73 m(2); p = 0.15) [corrected]. Although an increase in SCr >0.3 mg/dl from baseline was associated with increased risk of death or hospitalization for HF (hazard ratio [HR]: 1.36; p < 0.0001), the relationship was not significant if the change occurred before 4 months (HR: 1.09; p = 0.20). Despite increased risk of worsening renal function, 150 mg losartan was associated with reduced risk of death or hospitalization for HF compared with 50 mg (HR: 0.85; p < 0.0001). CONCLUSIONS: Compared with 50 mg, 150 mg losartan is associated with an increased risk of acute rise in SCr, as well as with greater long-term reductions in eGFR. Despite these effects, high-dose losartan retains its net clinical benefit and is associated with reduced risk of death or hospitalization for HF. (Study to Evaluate Potential Decrease in Hospitalization Events, Time Between Events, and Increasing Longevity in Patients With Symptomatic Heart Failure; NCT00090259).

Serum 25-hydroxyvitamin D and change in estimated glomerular filtration rate.

BACKGROUND AND OBJECTIVES: Mounting evidence suggests that 1,25-dihydroxyvitamin D prevents the progression of chronic kidney disease (CKD). It is not clear whether "nutritional" forms of vitamin D affect GFR. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We tested whether serum 25-hydroxyvitamin D concentration (25(OH)D), a measure of total vitamin D intake from cutaneous synthesis and dietary consumption, is associated with loss of estimated GFR among 1705 older adults with predominantly normal baseline kidney function participating in the Cardiovascular Health Study. Baseline 25(OH)D was measured by HPLC-tandem mass spectrometry. GFR was estimated at baseline and 4 years later using the CKD-EPI formula, with rapid GFR loss defined as 12 ml/min per 1.73 m(2) or more over 4 years. RESULTS: Rapid GFR loss was observed for 207 participants (12%). Each 10 ng/ml lower 25(OH)D was associated with a 25% greater risk of rapid GFR loss (95% confidence interval [CI] 5%, 49%, P = 0.01), adjusting for potential confounding characteristics. Compared with 25(OH)D ≥30 ng/ml, 25(OH)D concentrations 15 to 29 ng/ml and <15 ng/ml were associated with 29% (95% CI -13%, 91%) and 68% (95% CI 1%, 177%) greater adjusted risks of rapid GFR loss, respectively. Magnitudes of association were largest among participants with diabetes. RESULTS: were similar evaluating a composite outcome of rapid GFR loss, end stage renal disease, and death. Conclusions Insufficient 25(OH)D may be a modifiable risk factor for early GFR loss. We recommend clinical trials to determine whether vitamin D supplementation prevents the development and progression of CKD.

Markers of mineral metabolism are not associated with aortic pulse wave velocity in community-living elderly persons: the Health Aging and Body Composition study.

BACKGROUND: Disorders in mineral metabolism are associated with risk for cardiovascular disease (CVD) events in patients with kidney disease as well as in the general population. This risk is thought to be mediated, in part, through the mechanism of stiffening of the arteries. METHODS: The objective of this study was to evaluate the relationships between serum calcium, phosphorus, intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D levels and arterial pulse wave velocity (aPWV) among 2,229 community-dwelling elderly persons participating in the Health Aging and Body Composition (Health ABC) study. RESULTS: The mean age of the participants was 72 years; 52% were woman, 39% were black, and 17% had chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2)). In parallel unadjusted analyses, the following associations were observed: 2.86% greater aPWV per 12 ng/ml (s.d.) lower 25-hydroxyvitamin D (95% confidence interval -4.38%, -1.31%), 3.04% greater aPWV per 28 pg/ml (s.d.) higher iPTH (95% confidence interval 1.42-4.68%), and 2.37% lower aPWV per 0.5 mg/dl (s.d.) higher phosphorus (95% confidence interval -3.90% to - 0.81%). Except for phosphorus, these associations were attenuated and rendered no longer statistically significant after adjustment for demographic risk factors, clinical site, season, medications and other CVD risk factors. The results were similar in men and women and were not dependent on the presence of CKD. CONCLUSIONS: Among well-functioning community-dwelling elderly persons, only serum phosphorus was associated with aPWV; and this association was in the opposite direction of the one hypothesized. Factors other than vascular stiffening may mediate the relationship between disordered mineral metabolism and CVD events in community-living elders.

Effect of a very low-protein diet on outcomes: long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study.

BACKGROUND: The long-term effect of a very low-protein diet on the progression of kidney disease is unknown. We examined the effect of a very low-protein diet on the development of kidney failure and death during long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study. STUDY DESIGN: Long-term follow-up of study B of the MDRD Study (1989-1993). SETTING & PARTICIPANTS: The MDRD Study examined the effects of dietary protein restriction and blood pressure control on progression of kidney disease. This analysis includes 255 trial participants with predominantly stage 4 nondiabetic chronic kidney disease. INTERVENTION: A low-protein diet (0.58 g/kg/d) versus a very low-protein diet (0.28 g/kg/d) supplemented with a mixture of essential keto acids and amino acids (0.28 g/kg/d). OUTCOMES: Kidney failure (initiation of dialysis therapy or transplantation) and all-cause mortality until December 31, 2000. RESULTS: Kidney failure developed in 227 (89%) participants, 79 (30.9%) died, and 244 (95.7%) reached the composite outcome of either kidney failure or death. Median duration of follow-up until kidney failure, death, or administrative censoring was 3.2 years, and median time to death was 10.6 years. In the low-protein group, 117 (90.7%) participants developed kidney failure, 30 (23.3%) died, and 124 (96.1%) reached the composite outcome. In the very low-protein group, 110 (87.3%) participants developed kidney failure, 49 (38.9%) died, and 120 (95.2%) reached the composite outcome. After adjustment for a priori-specified covariates, hazard ratios were 0.83 (95% confidence interval, 0.62 to 1.12) for kidney failure, 1.92 (95% confidence interval, 1.15 to 3.20) for death, and 0.89 (95% confidence interval, 0.67 to 1.18) for the composite outcome in the very low-protein diet group compared with the low-protein diet group. LIMITATIONS: Lack of dietary protein measurements during follow-up. CONCLUSION: In long-term follow-up of the MDRD Study, assignment to a very low-protein diet did not delay progression to kidney failure, but appeared to increase the risk of death.

The Nutrition, Aging, and Memory in Elders (NAME) study: design and methods for a study of micronutrients and cognitive function in a homebound elderly population.

BACKGROUND: Micronutrient status can affect cognitive function in the elderly; however, there is much to learn about the precise effects. Understanding mediating factors by which micronutrient status affects cognitive function would contribute to elders' quality of life and their ability to remain in the home. OBJECTIVES: The Nutrition, Aging, and Memory in Elders (NAME) Study is designed to advance the current level of knowledge by investigating potential mediating factors by which micronutrient status contributes to cognitive impairment and central nervous system abnormalities in the elderly. NAME targets homebound elders because they are understudied and particularly at risk for poor nutritional status. METHODS: Subjects are community-based elders aged 60 and older, recruited through area Aging Services Access Points. The NAME core data include demographics; neuropsychological testing and activities of daily living measures; food frequency, health and behavioral questionnaires; anthropometrics; gene status; plasma micronutrients, homocysteine, and other blood determinants. A neurological examination, psychiatric examination, and brain MRI and volumetric measurements are obtained from a sub-sample. RESULTS: Preliminary data from first 300 subjects are reported. These data show that the NAME protocol is feasible and that the enrolled subjects are racially diverse, at-risk, and had similar basic demographics to the population from which they were drawn. CONCLUSION: The goal of the NAME study is to evaluate novel relationships between nutritional factors and cognitive impairment. These data may provide important information on potential new therapeutic strategies and supplementation standards for the elderly to maintain cognitive function and potentially reduce the public health costs of dementia.

Relationship of phosphorus and calcium-phosphorus product with mortality in CKD.

BACKGROUND: Abnormalities of mineral metabolism are prevalent in patients with kidney failure and are associated with increased risk for cardiovascular events. There are limited data investigating relationships of phosphorus and calcium-phosphorus product with outcomes in patients with chronic kidney disease (CKD) stages 3 to 4. METHODS: Serum phosphorus and calcium were measured at baseline in 840 participants from the randomized cohort of the Modification of Diet in Renal Disease Study. Survival status until December 31, 2000, was obtained from the National Death Index. Cox models were performed to assess the relationship of serum phosphorus level and calcium-phosphorus product with all-cause and cardiovascular disease (CVD) mortality. RESULTS: Mean serum phosphorus level was 3.8 +/- 0.7 mg/dL (1.23 +/- 0.23 mmol/L), calcium-phosphorus product was 34.7 +/- 6.3 mg2/dL2, and glomerular filtration rate (GFR) was 33 +/- 12 mL/min/1.73 m2 (0.55 +/- 0.20 mL/s/1.73 m2). All-cause and CVD mortality rates were 25% and 15%. Serum phosphorus level was not related to all-cause mortality in multivariable models (P = 0.46). In unadjusted analysis, serum phosphorus level was associated with (hazard ratio [HR] per 1 mg/dL increase, 1.34; 95% confidence interval [CI], 1.05 to 1.71; P = 0.02) increased risk for CVD mortality, but this association was partly attenuated and not statistically significant after adjustment for GFR and other confounders (HR, 1.27; 95% CI, 0.94 to 1.73; P = 0.12). Calcium-phosphorus product was not associated with all-cause mortality in unadjusted (P = 0.23) or multivariate analysis (P = 0.35). Calcium-phosphorus product was related to CVD mortality in unadjusted (HR per 10 mg2/dL2 increase, 1.30; 95% CI, 1.01 to 1.69; P = 0.04) analysis, but this association was not statistically significant after adjustment for GFR and other confounders (HR, 1.22; 95% CI, 0.89 to 1.66; P = 0.23). CONCLUSION: In the Modification of Diet in Renal Disease Study cohort, serum phosphorus level and calcium-phosphorus product were not statistically associated with all-cause or CVD mortality after adjustment for GFR; however larger studies with additional statistical power are needed to evaluate these relationships, especially in the context of current practice patterns in patients with CKD.

Homocysteine in chronic kidney disease: Effect of low protein diet and repletion with B vitamins.

BACKGROUND: Data are limited on the determinants of homocysteine (tHcy) and its relationship with nutritional indices, and dietary protein intake, in the earlier stages of chronic kidney disease (CKD). METHODS: Levels of tHcy were assayed at baseline (N= 804) and 1 year postrandomization (N= 678) in the Modification of Diet in Renal Disease (MDRD) Study [study A, glomerular filtration rate (GFR) 25 to 55 mL/min/1.73 m(2) and study B GFR 13 to 24 mL/min/1.73 m(2)]. Participants were randomly assigned to different blood pressure targets and protein diets and all subjects received a multivitamin supplement containing 1 mg of folic acid, 10 mg pyridoxal 5'-phosphate (PLP) and 6 mug of vitamin B(12). Multivariable analyses were used to evaluate determinants of tHcy at baseline and 1 year. RESULTS: The prevalence of hyperhomocysteinemia (tHcy >15 mumol/L) at baseline was 56% in study A and 85% in study B. Baseline tHcy was negatively correlated with measures of body fat and dietary protein intake. Folate, vitamin B(12), and GFR were the major determinants of tHcy levels. Of the patients with hyperhomocysteinemia at baseline, 49% and 24% reduced their tHcy levels at 1 year to < or =15 micromol/L in study A and study B, respectively. There was no association between dietary protein intake and odds of developing hyperhomocysteinemia at 1 year in study A (P= 0.94) or study B (P= 0.10). CONCLUSION: Hyperhomocysteinemia is partly amenable to correction by vitamin supplementation in CKD stages 3 and 4. There is insufficient evidence to suggest that low tHcy is associated with poor nutritional status in the MDRD Study cohort. B vitamins and GFR, but not dietary protein, are the major determinants of tHcy in this patient population.

Cardiovascular complications in chronic kidney disease.

The risk for cardiovascular disease (CVD) morbidity and mortality remains alarmingly high in all stages of chronic kidney disease (CKD). CVD often begins before end-stage renal disease (ESRD), and patients with reduced kidney function are more likely to die of CVD than to develop ESRD. Three pathological forms of CVD should be considered in patients with CKD: alterations in cardiac geometry, including left ventricular hypertrophy, atherosclerosis, and arteriosclerosis. All are highly prevalent in patients with CKD. Although patients with CKD share many of the same risk factors for CVD as the general population, there are a number of uremia-related risk factors, such as anemia and alterations in calcium/phosphorus metabolism, that also play a role in promoting CVD. Treatment of both traditional and uremia-related risk factors should be initiated in the earlier stages of CKD. Additional clinical trials with a goal to reduce CVD are urgently needed in CKD.