Hyperemesis gravidarum and vitamin K deficiency: a systematic review.

Hyperemesis gravidarum (HG), severe nausea and vomiting in pregnancy, can lead to vitamin deficiencies. Little is known about HG-related vitamin K deficiency. We aimed to summarise available evidence on the occurrence of HG-related vitamin K deficiency and corresponding maternal and neonatal complications. A systematic review was conducted, searching Medline and EMBASE from inception to 12 November 2020. We identified 1564 articles, of which we included fifteen in this study: fourteen case reports (n 21 women) and one retrospective cohort study (n 109 women). Nine out of twenty-one women reported in case reports had a prolonged prothrombin time (PT). The cohort study measured PT in 39/109 women with HG, of whom 10/39 women (26 %) had prolonged PT. In total, 30-50 % women received vitamin K supplementation after vitamin K deficiency had been diagnosed. Four case reports (n 4 women) reported corresponding maternal complications, all consisting of coagulopathy-related haemorrhage. Nine case reports (n 16 neonates) reported corresponding neonatal complications including intracranial haemorrhage (n 2 neonates) and embryopathy (n 14 neonates), which consisted of Binder phenotype (n 14 neonates), chondrodysplasia punctata (n 9 neonates) and grey matter heterotopia (n 3 neonates). In conclusion, vitamin K deficiency and related complications occur among women with HG. In our systematic review, we were unable to assess the incidence rate.

Vitamin K metabolism as the potential missing link between lung damage and thromboembolism in Coronavirus disease 2019.

Coronavirus disease 2019 (Covid-19), caused by severe acute respiratory syndrome coronavirus (SARS-CoV)-2, exerts far-reaching effects on public health and socio-economic welfare. The majority of infected individuals have mild to moderate symptoms, but a significant proportion develops respiratory failure due to pneumonia. Thrombosis is another frequent manifestation of Covid-19 that contributes to poor outcomes. Vitamin K plays a crucial role in the activation of both pro- and anticlotting factors in the liver and the activation of extrahepatically synthesised protein S which seems to be important in local thrombosis prevention. However, the role of vitamin K extends beyond coagulation. Matrix Gla protein (MGP) is a vitamin K-dependent inhibitor of soft tissue calcification and elastic fibre degradation. Severe extrahepatic vitamin K insufficiency was recently demonstrated in Covid-19 patients, with high inactive MGP levels correlating with elastic fibre degradation rates. This suggests that insufficient vitamin K-dependent MGP activation leaves elastic fibres unprotected against SARS-CoV-2-induced proteolysis. In contrast to MGP, Covid-19 patients have normal levels of activated factor II, in line with previous observations that vitamin K is preferentially transported to the liver for activation of procoagulant factors. We therefore expect that vitamin K-dependent endothelial protein S activation is also compromised, which would be compatible with enhanced thrombogenicity. Taking these data together, we propose a mechanism of pneumonia-induced vitamin K depletion, leading to a decrease in activated MGP and protein S, aggravating pulmonary damage and coagulopathy, respectively. Intervention trials should be conducted to assess whether vitamin K administration plays a role in the prevention and treatment of severe Covid-19.

Vitamin K deficiency-induced hemorrhagic shock after thoracentesis: a case report.

BACKGROUND: Vitamin K deficiency results in serious coagulation dysfunction, but hemorrhagic shock is rare. Herein, we describe a case of vitamin K deficiency and abnormality in the path of the intercostal artery, the combination of which led to hemorrhagic shock. CASE PRESENTATION: An 83-year-old woman was hospitalized for suspected gallstones. She developed septic shock after 4 days of hospitalization. We considered cholecystitis or cholangitis and performed abdominal ultrasonography, which revealed gallbladder enlargement, biliary sludge, and hyperplasia of the bile duct wall. Antibiotic treatment with sulbactam/ampicillin (SBT/ABPC) was initiated on day four, and percutaneous transhepatic gallbladder drainage (PTGBD) was performed on day five. The treatment was successful, but the patient developed bilateral pleural effusion because of hypoalbuminemia. We performed drainage for bilateral pleural effusion on days 13 and 17. The patient developed hypotension on day 18; blood tests showed anemia and severe coagulation dysfunction but a normal platelet count. We suspected vitamin K deficiency-induced coagulation dysfunction because of previous antibiotic treatment and restricted diet, and it led to hemorrhagic shock. Massive right hemothorax was observed by computed tomography, and urgent interventional radiology was performed. We observed no injury to the intercostal artery truncus but confirmed an abnormality in the course of the intercostal artery; therefore, we inferred that the cause of hemothorax in this case was injury to a small vessel, not truncus because of the abnormality. Because of the likelihood of rebleeding, we performed coil embolization from the seventh to the ninth intercostal artery. Because we confirmed vitamin K deficiency-induced coagulation dysfunction, we referred to the concentration of protein induced by vitamin K absence/antagonist-II (PIVKA-II), and it was found to increase by 23,000. CONCLUSIONS: A combination of vitamin K deficiency and abnormality in the course of the intercostal artery led to hemorrhagic shock. When using certain antibiotics and restricting diet, it is important to measure coagulation function, even if the platelet count is normal. Further, when thoracentesis is performed, abnormalities in the course of the intercostal artery should be identified. Thoracentesis with ultrasound may prevent hemothorax.

Fat soluble vitamin levels in children with newly diagnosed celiac disease, a case control study.

BACKGROUND: In children diagnosed with celiac disease, fat soluble vitamin levels were aimed to be evaluated and it was intended to determine whether fat soluble vitamin levels were needed to be assessed routinely in these patients during diagnosis. METHODS: Between May 2015-May 2016, diagnosis symptoms of celiac patients (CD) in newly diagnosed pediatric group were questioned, fat soluble vitamin levels simultaneous with intestinal biopsies were evaluated. Vitamin levels were compared with those of healthy control group. RESULTS: A total of 52 patients involving 27 female (51.9%), 25 male (48.1%); and a total of 50 healthy control group including 25 female (50%), 25 male (50%) were evaluated. The average age of patients was 9 ± 4.3 years, and their average weight was determined as 16.2 ± 6.3 kg. Growth retardation was the most frequent symptom in our patients (61.5%). Abdominal pain (51.9%) and diarrhea (11.5%) are among the other most commonly seen symptoms. In the histological examination of patients, Marsh 3B n = 23 (45.1%) was mostly established. Vitamin A and vitamin D levels of patients were determined significantly lower compared to those of control group. Vitamin A and vitamin D deficiencies were identified significantly higher compared to those of healthy control group. Vitamin D insufficiency was observed in 48 patients (92.3%) and vitamin D deficiency was determined in 32 (61.5%) out of 48. Vitamin A deficiency was established in 17 (32.7%) patients. Vitamin E and vitamin K1 deficiency were determined in no patients. In the healthy control group, vitamin D deficiency was seen in 2 (4%) patients, vitamin D insufficiency was determined in 9 (18%) patients. Other vitamin levels were identified at normal levels in the healthy group. CONCLUSIONS: In newly diagnosed children with CD, a significant lowness was established in vitamin D and A. The evaluation of vitamin A and D levels will be helpful in the course of diagnosis in these patients.

High Dephosphorylated-Uncarboxylated MGP in Hemodialysis patients: risk factors and response to vitamin K2, A pre-post intervention clinical trial.

BACKGROUND: Vascular calcifications are highly prevalent in hemodialysis patients. Dephosphorylated-uncarboxylated MGP (dp-ucMGP) was found to increase in vitamin K-deficient patients and may be associated with vascular calcifications. Supplementation of hemodialysis patients with vitamin K2 (menaquinone-7) has been studied in Europe with a maximum 61% drop of dp-ucMGP levels. The aim of this study is to assess first the drop of dp-ucMGP in an Eastern Mediterranean cohort after vitamin K2 treatment and second the correlation between baseline dp-ucMGP and vascular calcification score. METHODS: This is a prospective, pre-post intervention clinical trial involving 50 hemodialysis patients who received daily 360 µg of menaquinone-7 for 4 weeks. At baseline they were assessed for plasma dp-ucMGP levels and vascular calcification scores (AC-24) as well as for other demographic, clinical and biological variables. Dp-ucMGP levels were measured a second time at 4 weeks. RESULTS: At baseline, dp-ucMGP levels were extremely elevated with a median of 3179.15 (1825.25; 4339.50) pM and correlated significantly with AC-24 (Spearman's rho = 0.43, P = 0.002). Using a bivariate regression analysis, the association between dp-ucMGP levels and AC-24 was most significant when comparing dp-ucMGP levels less than 1000 to those more than 1000 pM (P = 0.02). Dp-ucMGP levels higher than 5000 pM were significantly associated with females, patients with recent fracture and patients with lower serum albumin (respectively P = 0.02, 0.004 and 0.046). The average drop of dp-ucMGP at 4 weeks of treatment was found to be 86% with diabetics having the lowest drop rate (P = 0.01). CONCLUSION: Vitamin K deficiency, as assessed by high dp-ucMGP levels, is profound in hemodialysis patients from the Eastern Mediterranean region and it is significantly correlated with vascular calcifications. Daily 360 µg of menaquinone-7, given for 4 weeks, effectively reduces dp-ucMGP in this population. Future studies are needed to assess the changes in vascular calcifications in hemodialysis patients treated with vitamin K2 over a longer follow-up period. TRIAL REGISTRATION: The clinical trial was registered on clinicaltrials.gov (Identification number NCT02876354 , on August 11, 2016).

Establishing a rat model for the study of vitamin K deficiency.

The main vitamin K-deficient model, minidose warfarin, is different from the pathological mechanism of vitamin K deficiency, which is a shortage of vitamin K. The objective of this study was to establish a new method of vitamin K-deficient model combining a vitamin K-deficient diet with the intragastrical administration of gentamicin in rats. The clotting was assayed by an automated coagulation analyser. The plasma PIVKA-II was assayed by ELISA. The vitamin K status was detected by an HPLC-fluorescence system. In the diet- and gentamicin-induced vitamin K-deficient 14-day group, the rats had undetected vitamin K1 and vitamin K2 in the liver and a prolonged APTT. In the 21-day group, there was also a prolonged PT and a decrease of the FIX activities. In the 28-day group, the undetected vitamin K1 and vitamin K2, the prolonged PT and APTT, and the decrease of the FII, FVII, FIX, and FX activities prompted the suggestion that there were serious deficiencies of vitamin K and vitamin K-dependent coagulation in rats. It is suggested that the diet- and gentamicin-induced vitamin K-deficient 14-day or 21-day model can be used for studies related to the status of vitamin K. The vitamin K-deficient 28-day model can be applied to research involving both the status of vitamin K and of vitamin K-dependent coagulation. In conclusion, the combination of a vitamin K-deficient diet with the administration of gentamicin results in a useful model of vitamin K-deficieny.

The prevalence of fat-soluble vitamin deficiencies and a decreased bone mass in patients with chronic pancreatitis.

BACKGROUND/OBJECTIVES: In chronic pancreatitis, malabsorption of fat is common due to loss of exocrine function. Consequently, these patients are at risk to acquire deficiencies of the fat-soluble vitamins, which may result in a decreased bone mineral density (BMD) and the development of osteopenia and osteoporosis. METHODS: We prospectively enrolled all patients diagnosed with chronic pancreatitis, who visited our outpatient clinic between March and November 2011. Data were collected regarding demographic characteristics, symptoms, and pancreatic function. Serum concentrations of vitamins A, E, K, and D were determined, and BMD was assessed by means of bone densitometry. Results were analyzed according to pancreatic function status and enzyme use, and compared to reference data, when available. RESULTS: Forty patients were included (43% female; mean age of 52). Alcohol abuse was the major cause of pancreatitis (50%). Twenty-eight patients were exocrine insufficient (70%), of whom 19 used pancreatic enzymes. Vitamin A, D, E, and K deficiencies were present in 3, 53, 10, and 63% of patients, respectively. Osteopenia and osteoporosis were observed in 45% and 10% of patients. A decreased BMD was more frequently observed than expected, based on reference data, even in exocrine sufficient patients. CONCLUSIONS: Deficiencies of fat-soluble vitamins and a decreased BMD are frequently present in chronic pancreatitis, even in exocrine sufficient patients. Consequently, all patients with chronic pancreatitis should be routinely screened for fat-soluble vitamin deficiencies and a decreased BMD.

Yellow is pale: the complications and challenges of late diagnosis of extrahepatic biliary atresia.

Extrahepatic biliary atresia classically presents in the neonatal period with jaundice and pale stools. The lack of bile pigment in stool can be unrecognised, delaying diagnosis and surgical treatment. Vitamin K is given at birth to reduce the risk of haemorrhagic disease of the newborn, but this may be inadequate to prevent the development of coagulopathy secondary to fat soluble vitamin malabsorption. We present the case of a 3 month old infant who presented with an intracerebral haemorrhage and coagulopathy thought to be secondary to fat malabsorption resulting from delayed diagnosis of extrahepatic biliary atresia. This was despite the perinatal administration of intramuscular vitamin K. His parents did not recognise the stool pallor as being abnormal. This case illustrates the importance of educating parents on the significance of pale stools, and also the risk of coagulopathy in extrahepatic biliary atresia despite perinatal intramuscular vitamin K.

[Undercarboxylated osteocalcin (Glu-OC) bone metabolism and vascular calcification in hemodialyzed patients]. / Niedokarboksylowana osteokalcyna (Glu-OC) a metabolizm kostny i kalcyfikacja naczyn u chorych hemodializowanych.

UNLABELLED: Osteocalcin (OC) is witamino-K dependent calcium-binding protein comprising three gamma carboxy glutamic acid residues (Gla) which determines a strong bond with hydroxyapatite. In vitamin K deficiency and/or increased bone resorption undercarboxylated osteocalcin (Glu-OC) appears in the blood. The aim of this study was to evaluate the level of Glu-OC and markers of bone metabolism and their impact on coronary artery calcification in patients with end-stage renal failure treated with repeated hemodialysis. The study included 68 patients (29 women and 39 men) aged 60.3 +/- 12.3 years hemodialysis period 24.5 +/- 4.8 months. Control group consisted of 35 healthy volunteers comparable in terms of age and gender. CACS was evaluated based on multislice spiral computed tomography (MSCT). Measurement of carboxylated osteocalcin (Gla-OC) and Glu-OC, bone alkaline phosphatase (bALP), tartrate-resistant acid phosphatase (TRAP5) were assessed by ELISA and iPTH by Nichols method. Present study demonstrated that the Gla-OC and Glu-OC in hemodialysis patients were significantly higher than the control group 116.37 +/- 70.01 ng/ml and 93.72 +/- 112.63 ng/ml versus 19.51 +/- 3.78 ng/ml and 4.88 +/- 2.63 ng/ ml; p <0.001. Glu-OC level correlated significantly with iPTH, bALP, TRAP5 (p <0.001) and CaSc (p <0.014). CONCLUSIONS: 1. The results indicate a significant correlation between Glu-OC and assessed markers of bone metabolism. 2. Research has indicated a link between bone metabolism and the degree of calcification in the coronary arteries.

Warfarin hypersensitivity due to gluten-sensitive enteropathy: a case study.

A 53 year old female who was maintained on long-term warfarin therapy due to history of pulmonary embolism, repeatedly presents with an abnormally prolonged Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT). After many asymptomatic episodes were corrected with Vitamin K therapy to temporarily reverse the effects of the warfarin, the cause of the apparent coagulopathy was further investigated. Factor Activity Assays of the common pathway factors II, IX, and X all revealed critically low values; below the threshold even a loading dose of warfarin is typically capable of eliciting. The patient tested strongly positive for Tissue Transglutaminase IgA, which is highly suggestive of a gluten-sensitive enteropathy. One effect of this condition is malabsorption due to flattened intestinal villi. The patient was determined to have an acquired vitamin K deficiency secondary to gluten-sensitive enteropathy. Her condition was exacerbated by the long-term warfarin therapy, resulting in the prolonged PT and PTT. The patient was treated with vitamin K therapy, which reversed the deficiency and corrected her abnormal coagulation results.

Vitamin K-Dependent Carboxylation of Osteocalcin in Bone-Ally or Adversary of Bone Mineral Status in Rats with Experimental Chronic Kidney Disease?

Chronic kidney disease (CKD) commonly occurs with vitamin K (VK) deficiency and impaired bone mineralization. However, there are no data explaining the metabolism of endogenous VK and its role in bone mineralization in CKD. In this study, we measured serum levels of phylloquinone (VK1), menaquinone 4 and 7 (MK4, MK7), and VK-dependent proteins: osteocalcin, undercarboxylated osteocalcin (Glu-OC), and undercarboxylated matrix Gla protein (ucMGP). The carboxylated osteocalcin (Gla-OC), Glu-OC, and the expression of genes involved in VK cycle were determined in bone. The obtained results were juxtaposed with the bone mineral status of rats with CKD. The obtained results suggest that the reduced VK1 level observed in CKD rats may be caused by the accelerated conversion of VK1 to the form of menaquinones. The bone tissue possesses all enzymes, enabling the conversion of VK1 to menaquinones and VK recycling. However, in the course of CKD with hyperparathyroidism, the intensified osteoblastogenesis causes the generation of immature osteoblasts with impaired mineralization. The particular clinical significance seems to have a finding that serum osteocalcin and Glu-OC, commonly used biomarkers of VK deficiency, could be inappropriate in CKD conditions, whereas Gla-OC synthesized in bone appears to have an adverse impact on bone mineral status in this model.

Hydrolysed formula is a risk factor for vitamin K deficiency in infants with unrecognised cholestasis.

OBJECTIVES: Vitamin K deficiency (VKD) may cause life-threatening haemorrhages, especially in breast-fed infants with unrecognised cholestasis. Interestingly, hypoallergenic formulas appear overrepresented in reported cases of VKD bleeding (VKDB) in formula-fed infants. We therefore assessed whether the risk of VKD in formula-fed infants with cholestasis is associated with hypoallergenic formulas. PATIENTS AND METHODS: Infants born in the Netherlands between January 1991 and December 2006 with cholestatic jaundice due to biliary atresia (BA) or to α-1-antitrypsin deficiency (A1ATD) were identified in the Netherlands Study Group for Biliary Atresia Registry and the A1ATD registry, respectively. The relative risk (RR) of VKDB in patients with BA or A1ATD was calculated for different formula types. The influence of prior or ongoing breast-feeding on the RR of VKDB was also assessed. RESULTS: A total of 179 infants with either BA (139) or A1ATD (40) were included. One hundred eighteen infants were formula fed; 8 presented with VKD. Six of these 8 infants (75%) received hypoallergenic formula (whey-based hydrolysate in 4). One infant on whey-based hydrolysed formula presented with VKDB. Risk factor analysis revealed that infants receiving hydrolysed, especially whey-based, formula, had a strongly increased risk of VKD (RR 25.0 [6.4-97.2], P < 0.001)) compared with infants receiving regular formula. Prior or ongoing breast-feeding was not significantly associated with VKD. CONCLUSIONS: Infants with cholestasis receiving (whey-based) hydrolysed formula are at increased risk of developing VKD, compared with infants receiving regular formula. Because VKD may lead to serious haemorrhages, infants receiving whey-based hydrolysed formulas may need additional vitamin K supplementation.

Awareness of glucose-6 phosphate-dehydrogenase deficiency in celiac disease.

UNLABELLED: Individuals with celiac disease (CD) are predisposed to a number of haematological abnormalities including anaemia secondary to malabsorption of iron, vitamin B12 or folate; anaemia of chronic disease and coagulopathy secondary to vitamin K deficiency. Correction of coagulopathy with vitamin K is necessary before endoscopic biopsy in patients with suspected CD. However, vitamin K causes haemolysis in glucose-6 phosphate-dehydrogenase deficiency. CONCLUSION: When vitamin K administration becomes necessary for correction of coagulopathy in patients with CD; glucose-6 phosphate-dehydrogenase deficiency should be considered.

Coagulation disorder as a presentation of cystic fibrosis.

Cystic fibrosis (CF) is the most common life-limiting inherited disease in the Caucasian population. Coagulation disorder in infancy is a rare presentation of CF, with few recent cases reported in the English literature. We report a case of an infant with CF who presented to our hospital with bruising, occult gastrointestinal bleeding, and anemia secondary to vitamin K deficiency.

[Dementia and fracture].

A high incidence of fractures, particularly of the hip, represents an important problem in patients with AD, who are prone to falls and may have osteoporosis. The odds ratio reported for fracture prevalence between elderly persons with and without AD is 6.9. We previously demonstrated that deficiency of 25-hydroxyvitamin D due to sunlight deprivation and vitamin K deficiency due to malnutrition contributed to reduced bone mineral density in patients with AD and were associated with a high risk of hip fracture. Treatment with menatetrenone, risedronate or regular sunlight exposure are safe and effective in increasing bone mass and reducing the risk of hip fracture in patients with AD.

Treatment to reduce vascular calcification in hemodialysis patients using vitamin K (Trevasc-HDK): A study protocol for a randomized controlled trial.

INTRODUCTION: End stage renal failure patients on hemodialysis have significant vascular calcification This is postulated to be related to sub-clinical vitamin K deficiency, which is prevalent in hemodialysis patients. Vitamin K deficiency result in the failure of the matrix GLA protein (MGP) to undergo carboxylation. MGP is a natural local inhibitor of vascular calcification and the lack of functional carboxylated MGP may contribute to increase vascular calcification. Vitamin K supplement should therefore correct this anomaly and decrease the rate or severity of vascular calcification in this population of patients on long-term maintenance hemodialysis. Our study seeks to evaluate the prevalence and the progression of vascular calcification in a cohort of maintenance hemodialysis patients. It will also evaluate the efficacy of vitamin K supplementation in reducing the progression of vascular calcification in this group of patients. METHODS: This will be a single-center randomized, prospective and open-label interventional clinical trial of end stage renal failure patients on hemodialysis. We aim to recruit 200 patients. Eligible patients will be randomized to either the standard care arm or active treatment arm. Active treatment arm patients will receive standard care plus supplementation with oral vitamin K2 isoform 360 mcg 3 times weekly for a total duration of 18 months. Primary outcome measured will be absolute difference in coronary artery calcification score at 18-month between control and intervention arms. Secondary outcomes will be to compare absolute difference in aortic valve calcification, percentage of patients with regression of coronary artery calcification of at least 10%, absolute difference in aortic and systemic arterial stiffness, mortality from any cause and major adverse cardiovascular over the same period. DISCUSSION: Evidence of successful regression or retardation of vascular calcification will support the conduct of larger and longer-term trials aimed at reducing cardiovascular disease mortality and major adverse cardiovascular events in this high-risk population using a safe and inexpensive strategy TRIAL REGISTRATION:: ClinicalTrials.gov NCT02870829. Registered on 17 August 2016 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02870829National University Hospital's Institutional Review Board (2015/01000).

The Relationship between Vitamin K and Osteoarthritis: A Review of Current Evidence.

Vitamin K is a cofactor of γ-glutamyl carboxylase, which plays an important role in the activation of γ-carboxyglutamate (gla)-containing proteins that negatively regulate calcification. Thus, vitamin K status might be associated with osteoarthritis (OA), in which cartilage calcification plays a role in the pathogenesis of the disease. This review collates the evidence on the relationship between vitamin K status (circulating or dietary intake level of vitamin K, or circulating uncarboxylated gla proteins) and OA from human observational studies and clinical trial, to examine its potential as an agent in preventing OA. The current literature generally agrees that a sufficient level of vitamin K is associated with a lower risk of OA and pathological joint features. However, evidence from clinical trials is limited. Mechanistic study shows that vitamin K activates matrix gla proteins that inhibit bone morphogenetic protein-mediated cartilage calcification. Gla-rich proteins also inhibit inflammatory cascade in monocytic cell lines, but this function might be independent of vitamin K-carboxylation. Although the current data are insufficient to establish the optimal dose of vitamin K to prevent OA, ensuring sufficient dietary intake seems to protect the elderly from OA.

Severe Rifampicin-induced Vitamin K Deficiency Coagulopathy in a Child.

An 8-month-old child under tuberculosis treatment presented with multiple ecchymotic lesions. A severe coagulopathy was evidenced compatible with vitamin K deficiency [II (3%), VII (2%), IX (3%) and X (1%)]. It was reversed with vitamin K and plasma administration. Rifampicin-induced vitamin K deficiency is very rare, reported only once before, possibly related to an inhibition of vitamin K cycle.

Causes of Vitamin K Deficiency in Patients on Haemodialysis.

Background: A low vitamin K status is common in patients on haemodialysis, and this is considered one of the reasons for the accelerated atherosclerosis in these patients. The vitamin is essential in activation of the protein Matrix Gla Protein (MGP), and the inactive form, dp-ucMGP, is used to measure vitamin K status. The purpose of this study was to investigate possible underlying causes of low vitamin K status, which could potentially be low intake, washout during dialysis or inhibited absorption capacity. Moreover, the aim was to investigate whether the biomarker dp-ucMGP is affected in these patients. Method: Vitamin K intake was assessed by a Food Frequency Questionnaire (FFQ) and absorption capacity by means of D-xylose testing. dp-ucMGP was measured in plasma before and after dialysis, and phylloquinine (vitamin K1) and dp-ucMGP were measured in the dialysate. Changes in dp-ucMGP were measured after 14 days of protein supplementation. Results: All patients had plasma dp-ucMGP above 750 pmol/L, and a low intake of vitamin K. The absorption capacity was normal. The difference in dp-ucMGP before and after dialysis was -1022 pmol/L (p < 0.001). Vitamin K1 was not present in the dialysate but dp-ucMGP was at a high concentration. The change in dp-ucMGP before and after protein supplementation was -165 pmol/L (p = 0.06). Conclusion: All patients had vitamin K deficiency. The reason for the low vitamin K status is not due to removal of vitamin K during dialysis or decreased absorption but is plausibly due to a low intake of vitamin K in food. dp-ucMGP is washed out during dialysis, but not affected by protein intake to a clinically relevant degree.