Associations of vitamin K status with mortality and cardiovascular events in peritoneal dialysis patients

Vitamin K for Vascular Calcification in Kidney Patients: Still Alive and Kicking, but Still a Lot to Learn

Patients with chronic kidney disease (CKD) suffer disproportionately from a high burden of cardiovascular disease, which, despite recent scientific advances, remains partly understood. Vascular calcification (VC) is the result of an ongoing process of misplaced calcium in the inner and medial layers of the arteries, which has emerged as a critical contributor to cardiovascular events in CKD. Beyond its established role in blood clotting and bone health, vitamin K appears crucial in regulating VC via vitamin K-dependent proteins (VKDPs). Among these, the matrix Gla protein (MGP) serves as both a potent inhibitor of VC and a valuable biomarker (in its inactive form) for reflecting circulating vitamin K levels. CKD patients, especially in advanced stages, often present with vitamin K deficiency due to dietary restrictions, medications, and impaired intestinal absorption in the uremic environment. Epidemiological studies confirm a strong association between vitamin K levels, inactive MGP, and increased CVD risk across CKD stages. Based on the promising results of pre-clinical data, an increasing number of clinical trials have investigated the potential benefits of vitamin K supplementation to prevent, delay, or even reverse VC, but the results have remained inconsistent.

Vascular calcification inhibitors and cardiovascular events in peritoneal dialysis patients

The prevalence of cardiovascular diseases is high among patients with chronic kidney disease (CKD) and peritoneal dialysis (PD) patients, which increases morbidity and mortality in this population and represents a significant financial burden for both the patients and the healthcare systems. Vascular calcification (VC) is associated with increased morbidity and mortality and VC risk is higher in patients with CKD than in healthy individuals. Calcification inhibitors, compounds that inhibit VC, were discovered as a result of efforts to explain why some patients are spared. It was found that certain proteins (e.g., fetuin-A, osteopontin, osteoprotegerin, bone morphogenetic protein-7) inhibit calcification in dialysis patients. In this narrative review, we provide an overview of known calcification inhibitors, describe the relevant regulatory mechanisms, and discuss their relation to VC development in PD patients.

Development of standardized nursing terminology for the process documentation of patients with chronic kidney disease

Introduction

European Nursing care Pathways (ENP) is a professional care language that utilizes software to map care processes and utilize the data for research purposes, process control, and personnel requirement calculations. However, there is a lack of internationally developed terminology systems and subset specifically designed for the nutritional management of CKD. The aim of this study was to create a subset of the standardized nursing terminology for nutrition management in patients with chronic kidney disease (CKD).

Materials and methods

According to the guidelines for subset development, four research steps were carried out: (i) Translation of version 3.2 of the ENP (chapter on kidney diseases) and understanding of the framework structure and coding rules of the ENP; (ii) Identification of relevant six-dimensional nursing terms; (iii) Creation of a framework for the subset; (iv) Review and validation by experts.

Results

A subset for CKD nutritional care was created as part of this project, comprising 630 terms, with 17 causal relationships related to nursing diagnoses, 115 symptoms, 31 causes, 34 goals/outcomes, 420 intervention specifications and 13 resources, including newly developed care terms. All terms within the subset have been created using a six-step maintenance procedure and a clinical standard pathway for nutrition management in the SAPIM mode.

Implications for nursing practice

This terminology subset can facilitate standardized care reports in CKD nutrition management, which is used to standardize nursing practice, quantify nursing, services, guidance on care decisions, promoting the exchange and use of CKD nutrition data and serve as a reference for the creation of standardized subset of nursing terminology in China.

Malnutrition accelerates the occurrence of infectious complications in patients with chronic kidney disease: A cross-sectional survey of 682 patients with chronic kidney disease

BACKGROUND

To investigate the influencing factors of infectious complications in patients with chronic kidney disease (CKD) and provide a basis for clinical diagnosis and prognosis evaluation of CKD.

METHODS

A total of 682 patients with CKD were selected and divided into CKD stage 1-5 subgroups according to their glomerular filtration rate. Infectious complications, length of hospital stay, and total cost of hospitalization were recorded. The Global Leadership Initiative on Malnutrition (GLIM) diagnostic tool was used to assess the detection rate of malnutrition among patients. Univariate and multivariate analyses were performed in patients with and without infectious complications.

RESULTS

The incidence rates of infectious complications in CKD stages 1-5 were 45.6%, 22.7%, 28.3%, 30.8%, and 40.4%, respectively. The overall detection rate of malnutrition among patients based on the GLIM criteria was 16.7%. The total detection rate of severe malnutrition was 14.2%, with all patients with severe malnutrition in CKD stages 3-5. The incidences of infectious complications in patients with and without malnutrition were 62.3% and 29%, respectively. Binary multivariate logistic regression analysis shows that malnutrition is a risk factor for infectious complications in patients with CKD, who are at 2.41 times higher risk than patients without malnutrition. There were significant differences in length of hospital stay and hospitalization costs between the patients with CKD with and without infectious complications (P < 0.01).

CONCLUSION

Infectious complications are relatively common in patients with CKD. As CKD advances, the incidence of infectious complications increases. Moreover, malnutrition accelerates the occurrence of infectious complications in patients with CKD.

Plant or Animal-Based or PLADO Diets: Which Should Chronic Kidney Disease Patients Choose?

Nutrition therapy is the cornerstone treatment for chronic kidney disease (CKD). Although much attention has been given to dietary protein intake in CKD patients, many findings now demonstrate that the type of dietary protein intake may be more critical for CKD patients. In protein bioavailability and malnutrition prevention, many physicians recommend that CKD patients adhere to a low protein diet and restrict their plant foods, such as vegetables, fruits, and soybeans. However, nephrologists should not ignore the potential benefits of plant foods for CKD patients. It is not advisable to restrict the intake of plant foods in the later stage of CKD simply to prevent the development of hyperkalemia and malnutrition. This article highlights the benefits and possible problems of a plant-dominant low protein diet (PLADO) diet, defined as an LPD with dietary protein intake of 0.6-0.8 g/kg/day with at least 50% plant-based source for CKD patients. We hope to provide new opinions for clinical work and CKD patients.

Analysis of malnutrition factors for inpatients with chronic kidney disease

Objective

Malnutrition is a common complication of Chronic Kidney Disease (CKD), and it is the risk factor of CKD prognosis. This study aim to evaluate the nutritional status of inpatients with CKD by using the Subjective Global Assessment (SGA), and to analyze the related factors of malnutrition; and to provide effective reference for early detection of malnutrition status in patients with CKD and timely nutrition intervention.

Methods

A total of 426 patients (238 male patients, 188 female patients) aged 62.62 ± 14.61 and 61.14 ± 14.82, respectively admitted to the Nephrology Department of Wannan Medical College from February 2020 to December 2020 were selected and included in to this study by convenience sampling. 426 patients with CKD were evaluated by SGA. Human body weight, hemoglobin (Hb), total protein (TP), albumin (ALB), pre-albumin (PA), qualitative analysis of urinary protein and other laboratory indexes were collected and measured. The correlation between malnutrition and age, education, gender, diet, CKD stage and other factors was analyzed by spearman correlation analysis.

Results

The incidence of malnutrition was 85.7% among 426 patients with CKD. Gender, age, education level, CKD stage, diabetes mellitus, weight loss and reduced food intake were related to SGA nutritional assessment (P < 0.05). The expression levels of ALB, PA and Hb in the malnutrition group were significantly lower than those in the normal group (P < 0.05). The degree of malnutrition in CKD patients was significant negatively correlated with the expression levels of ALB (r = -0.188), PA (r = -0.262) and Hb (r = -0.176) (P < 0.05). The multivariate Logistic regression analysis model showed that female (OR = 2.155), ≥60 years old (OR = 7.671), weight loss (OR = 10.691), reduced food intake (OR = 28.953), moderate and severe serum ALB expression (OR = 3.391 and 8.326) were risk factors for malnutrition in patients with CKD (P < 0.05). Malnutrition was correlated with the results of qualitative examination of urinary protein (r = 0.268, P < 0.05).

Conclusion

Gender, age, weight loss, reduced food intake, serum ALB expression were independently associated with malnutrition in patients with chronic kidney disease, Hence, the medical staff should take timely and effective nutrition intervention for the patients with malnutrition, delay the renal function damage of patients with CKD and improve the quality of life of patients. Inpatients with CKD, especially women, should increase their dietary intake, maintain normal weight and improve their nutritional status.

Association of Vitamin K Status with Arterial Calcification and Stiffness in Chronic Kidney Disease: The Chronic Renal Insufficiency Cohort

Background

Arterial calcification and stiffness are common in people with chronic kidney disease (CKD). Higher vitamin K status has been associated with less arterial calcification and stiffness in CKD in cross-sectional studies.

Objectives

To determine the association of vitamin K status with coronary artery calcium (CAC) and arterial stiffness [pulse wave velocity (PWV)] at baseline and over 2-4 follow-up years in adults with mild-to-moderate CKD.

Methods

Participants (n = 2722) were drawn from the well-characterized Chronic Renal Insufficiency Cohort. Two vitamin K status biomarkers, plasma phylloquinone and plasma dephospho-uncarboxylated matrix gla protein [(dp)ucMGP], were measured at baseline. CAC and PWV were measured at baseline and over 2-4 y of follow-up. Differences across vitamin K status categories in CAC prevalence, incidence, and progression (defined as ≥100 Agatston units/y increase) and PWV at baseline and over follow-up were evaluated using multivariable-adjusted generalized linear models.

Results

CAC prevalence, incidence, and progression did not differ across plasma phylloquinone categories. Moreover, CAC prevalence and incidence did not differ according to plasma (dp)ucMGP concentration. Compared with participants with the highest (dp)ucMGP (≥450 pmol/L), those in the middle category (300-449 pmol/L) had a 49% lower rate of CAC progression (incidence rate ratio: 0.51; 95% CI: 0.33, 0.78). However, CAC progression did not differ between those with the lowest (<300 pmol/L) and those with the highest plasma (dp)ucMGP concentration (incidence rate ratio: 0.82; 95% CI: 0.56, 1.19). Neither vitamin K status biomarker was associated with PWV at baseline or longitudinally.

Conclusions

Vitamin K status was not consistently associated with CAC or PWV in adults with mild-to-moderate CKD.

VItamin K In PEritonial DIAlysis (VIKIPEDIA): Rationale and study protocol for a randomized controlled trial

Vascular calcification (VC) is an active process, resulting from the disturbance of balance between inhibitors and promoters of calcification, in favor of the latter. Matrix Gla Protein, a powerful inhibitor of VC, needs vitamin K to become active. In vitamin K depletion, plasma levels of the inactive form of MGP, dephosphorylated, uncarboxylated MGP (dp-ucMGP) are increased and associated with VC and cardiovascular (CV) outcomes. End Stage Renal Disease (ESRD) patients have increased circulating dp-ucMGP levels and accelerated VC. VItamin K In PEritoneal DIAlysis (VIKIPEDIA) is a prospective, randomized, open label, placebo-controlled trial, evaluating the effect of vitamin K2 supplementation on arterial stiffness and CV events in ESRD patients undergoing peritoneal dialysis (PD). Forty-four PD patients will be included in the study. At baseline, dp-ucMGP and pulse-wave velocity (PWV) will be assessed and then patients will be randomized (1:1 ratio) to vitamin K (1000 μg MK-7/day) or placebo for 1.5 years. The primary endpoint of this trial is the change in PWV in the placebo group as compared to the treatment group. Secondary endpoints are the occurrence of CV events, mortality, changes in PD adequacy, change in 24-hour ambulatory blood pressure indexes and aortic systolic blood pressure and changes in calcium/phosphorus/parathormone metabolism. VIKIPEDIA is a new superiority randomized, open label, placebo-controlled trial aiming to determine the effect of vitamin K2 supplementation on VC, CV disease and calcium/phosphorus metabolism, in PD patients.

Trial registration: The protocol of this study is registered at ClinicalTrials.gov with identification number NCT04900610 (25 May 2021).

Vitamin K and vascular calcification in chronic kidney disease: An update of current evidence

Vascular calcification, characterized by calcium deposition in the intimal and medial layers of the arterial wall, is frequently encountered in patients with chronic kidney disease (CKD) and leads to an enhanced risk of adverse cardiovascular (CV) outcomes. However, the underlying complex pathophysiology remains incompletely understood. Recently, Vitamin K supplementation aimed at correcting Vitamin K deficiency highly prevalent in CKD holds great promise to mitigate the progression of vascular calcification. This article discusses the functional Vitamin K status in CKD, the pathophysiology linking Vitamin K deficiency and vascular calcification, and reviews current literature from animal models, observational studies, and clinical trials across the different spectrum of CKD. While favorable effects of Vitamin K on vascular calcification and CV outcomes are suggested in animal and observational studies, most recently published clinical trials investigating the effects of Vitamin K on vascular health failed to support the beneficial role of Vitamin K supplementation, despite improving the functional status of Vitamin K. We address the potential reasons for these discrepancies and provide further perspective on Vitamin K research in CKD.

Vitamin K status, all-cause mortality, and cardiovascular disease in adults with chronic kidney disease: the Chronic Renal Insufficiency Cohort

BACKGROUND

Vascular calcification contributes to cardiovascular disease (CVD) and mortality in individuals with chronic kidney disease (CKD). Vitamin K-dependent proteins function as calcification inhibitors in vascular tissue.

OBJECTIVES

We sought to determine the association of vitamin K status with mortality and CVD events in adults with CKD.

METHODS

Plasma dephospho-uncarboxylated matrix gla protein ((dp)ucMGP), which increases when vitamin K status is low, and plasma phylloquinone (vitamin K1), which decreases when vitamin K status is low, were measured in 3066 Chronic Renal Insufficiency Cohort participants (median age = 61 y, 45% female, 41% non-Hispanic black, median estimated glomerular filtration rate [eGFR] = 41 mL/min/1.73m2). The association of vitamin K status biomarkers with all-cause mortality and atherosclerotic-related CVD was determined using multivariable Cox proportional hazards regression.

RESULTS

There were 1122 deaths and 599 atherosclerotic CVD events over the median 12.8 follow-up years. All-cause mortality risk was 21-29% lower among participants with plasma (dp)ucMGP <450 pmol/L (n = 2361) compared with those with plasma (dp)ucMGP ≥450 pmol/L (adjusted HRs [95% CIs]: <300 pmol/L = 0.71 [0.61, 0.83], 300-449 pmol/L = 0.77 [0.66, 0.90]) and 16-19% lower among participants with plasma phylloquinone ≥0.50 nmol/L (n = 2421) compared to those with plasma phylloquinone <0.50 nmol/L (adjusted HRs: 0.50, 0.99 nmol/L = 0.84 [0.72, 0.99], ≥1.00 nmol/L = 0.81 [0.70, 0.95]). The risk of atherosclerotic CVD events did not significantly differ across plasma (dp)ucMGP or phylloquinone categories.

CONCLUSIONS

Two biomarkers of vitamin K status were associated with a lower all-cause mortality risk but not atherosclerotic CVD events. Additional studies are needed to clarify the mechanism underlying this association and evaluate the impact of improving vitamin K status in people with CKD.

Kidney function and cancer risk: An analysis using creatinine and cystatin C in a cohort study

BACKGROUND

We examined whether an increased risk of cancer incidence and death is associated with kidney function and albuminuria and whether the risk is more readily identified when kidney function is estimated using cystatin C.

METHODS

Participants were from UK Biobank (recruitment spanning 2007-2010), excluding those with a prior diagnosis of cancer. Estimated glomerular filtration rate (ml/min/1.73m2) was calculated using creatinine (eGFRcr), cystatin C (eGFRcys) and creatinine-cystatin C (eGFRcr-cys). Cox proportional hazards models tested associations between eGFR, urinary albumin:creatinine ratio (uACR) and cancer incidence and death.

FINDINGS

In 431,263 participants over median follow-up of 11.3 (IQR 10.6-12.0) years, there were 41,745 incident cancers and 11,764 cancer deaths. eGFRcys was most strongly associated with cancer incidence and death (HR 1.04 (95% CI 1.03-1.04) and 1.06 (1.05-1.07) per 10 ml/min/1.73m2 decline, respectively). eGFRcr was not associated with either outcome (incidence: HR 1.00 (1.00-1.01); death: HR 0.99 (0.98-1.01) per 10 ml/min/1.73m2 decline). Relative to eGFRcys>90 or uACR<3 mg/mmol, eGFRcys60-89 (HR 1.04 (95% CI 1.02-1.07)), eGFRcys<60 (HR 1.19 (1.14-1.24)) and uACR≥3 mg/mmol (HR 1.09 (1.06-1.12)) were associated with higher risk of incident cancer. eGFRcys60-89 (HR 1.15 (1.10-1.21)); eGFRcys<60 (HR 1.48 (1.38-1.59)) and uACR≥3 mg/mmol (HR 1.17 (1.11-1.24)) were associated with cancer death.

INTERPRETATION

Excess risk of cancer incidence and cancer death is more readily captured in early chronic kidney disease by eGFRcys than by current measures. The association between kidney function, uACR and cancer death in particular is concerning and warrants further scrutiny.

FUNDING

Chief Scientist Office; ANID Becas Chile; Medical Research Council; British Medical Association; British Heart Foundation.

Role of Vitamin K in CKD: Is Its Supplementation Advisable in CKD Patients?

BACKGROUND

Patients with CKD are at an increased risk of developing vascular calcification (VC) and bone complications which translate into a higher morbidity and mortality. The dephosphorylated and uncarboxylated matrix Gla protein (dp-ucMGP) is considered to be an indicator of vitamin K2 status and correlates with markers of VC. It is activated by γ-glutamyl carboxylase that converts inactive MGP into an active form, and vitamin K2 is a cofactor of this reaction. The active form of MGP is a known inhibitor of arterial wall calcification and plays an important role in bone turnover. Recent studies show poor vitamin K2 status in CKD patients. We aimed to review the literature for the association between vitamin K2 status and calcification and bone disease risk and the efficacy of vitamin K2 supplementation in CKD population.

SUMMARY

Most CKD patients, including those on renal replacement therapy, have vitamin K2 deficiency. The dp-ucMGP level, a marker of vitamin K2 status, is decreased by vitamin K2 supplementation in CKD patients, but there is no unequivocal proof that it influences arterial calcification progression and bone complications. Key Messages: CKD population are at risk of vitamin K deficiency. Supplementation of vitamin K2 is safe and improves the serum markers of its deficiency. There is lack of strong evidence that vitamin K2 supplementation slows progression of calcification or reduces the frequency of bone complications. More prospective studies are needed.

Vitamin K for the Treatment of Cardiovascular Disease in End-Stage Renal Disease Patients: Is there Hope?

In Chronic Kidney Disease, vascular calcification (VC) is highly prevalent even at early stages and is gradually enhanced, along with disease progression to End-Stage Renal Disease (ESRD). The calcification pattern in uremia includes all types of mineralization and contributes to the heavy cardiovascular (CV) burden that is common in these patients. Ectopic mineralization is the result of the imbalance between inhibitors and promoters of vascular calcification, with the latter overwhelming the former. The most powerful, natural inhibitor of calcification is Matrix Gla Protein (MGP), a small vitamin K dependent protein, secreted by chondrocytes and vascular smooth muscle cells. In uremia, MGP was reported as the only molecule able to reverse VC by "sweeping" calcium and hydroxyapatite crystals away from the arterial wall. To become biologically active, this protein needs to undergo carboxylation and phosphorylation, reactions highly dependent on vitamin K status. The inactive form of MGP reflects the deficiency of vitamin K and has been associated with CV events and mortality in ESRD patients. During the past decade, vitamin K status has emerged as a novel risk factor for vascular calcification and CV disease in various populations, including dialysis patients. This review presents evidence regarding the association between vitamin K and CV disease in ESRD patients, which are prone to atherosclerosis and atheromatosis.

Vascular Calcification in Chronic Kidney Disease: The Role of Vitamin K- Dependent Matrix Gla Protein

Arterial calcification is highly prevalent in chronic kidney disease (CKD) patients and is associated with cardiovascular (CV) morbidity and mortality. Patients at early CKD stages are more likely to suffer a fatal CV event than to develop end-stage renal disease and require hemodialysis treatment. The heavy CV burden of these patients cannot be solely explained by traditional calcification risk factors. Moreover, the pathophysiologic mechanisms underlying this association are complex and yet not fully understood. Although vascular calcification was regarded as a passive degenerative process for over a century, this theory changed by recent evidence that pointed toward an active process, where calcification promoters and inhibitors were involved. Matrix Gla Protein (MGP) has been established as a strong inhibitor of calcification both in vitro and in vivo. Not only it prevents mineralization of the arterial wall, but it is the only factor that can actually reverse it. To become fully active, MGP must undergo carboxylation of specific protein bound glutamate residues, a process fully dependent on the availability of vitamin K. Low vitamin K status leads to inactive, uncarboxylated forms of MGP and has been repeatedly associated with accelerated vascular calcification. Aim of this review is to present the pathophysiologic mechanisms underlying the activation and function of MGP and review the existing, accumulating data regarding the association between vitamin K, MGP and vascular calcification/CV disease in CKD patients.