Association between 25-hydroxyvitamin D, somatic muscle weakness and falls risk in end-stage renal failure

Association between Serum 25-Hydroxyvitamin D Levels and Sarcopenia in Patients Undergoing Chronic Haemodialysis

INTRODUCTION

Sarcopenia and vitamin D deficiency are highly prevalent among patients undergoing haemodialysis. Although vitamin D deficiency, assessed using serum 25-hydroxyvitamin D (25(OH)D) levels, is known to be associated with sarcopenia in the general population, whether serum 25(OH)D levels are associated with sarcopenia in patients undergoing haemodialysis with suppressed renal activation of 25(OH)D remains unclear. This study aimed to examine the association between serum 25(OH)D levels and sarcopenia in patients undergoing haemodialysis.

METHODS

Serum 25(OH)D level measurements and assessment of sarcopenia using the Asian Working Group for Sarcopenia criteria were conducted in 95 stable outpatients undergoing maintenance haemodialysis therapy.

RESULTS

Sarcopenia was observed in 22 (23.1%) patients. In multiple logistic regression analysis, serum 25(OH)D levels were associated with sarcopenia (odds ratio [OR] 0.87, 95% confidence interval [CI] 0.77-0.99, p = 0.039) independent of traditional risk factors for sarcopenia. In multiple linear regression analyses, serum 25(OH)D levels were associated with parameters of skeletal muscle mass and strength (β = 0.145, p = 0.046, and β = 0.194, p = 0.020, respectively). The adjusted OR for sarcopenia was 5.60 (95% CI 1.52-20.57, p = 0.009) in the vitamin D deficiency group categorized based on the cut-off serum 25(OH)D level of 10 ng/mL. Regarding model discrimination, adding vitamin D deficiency to the traditional risk factors significantly improved the integrated discrimination improvement score (0.093, p = 0.007).

CONCLUSION

Lower serum 25(OH)D levels were associated with sarcopenia independent of traditional risk factors in patients undergoing haemodialysis with suppressed vitamin D activation in the kidney. This finding implies that circulating 25(OH)D may have an important relationship with the skeletal muscle function of patients undergoing haemodialysis, and its measurement may be recommended to identify patients at high risk for sarcopenia among those undergoing haemodialysis.

Vitamin Needs and Treatment for Chronic Kidney Disease Patients

This paper summarizes the biochemistry, metabolism, and dietary needs of vitamins in patients with chronic kidney disease (CKD) and kidney transplant recipients. Evidence indicates that the dietary intake, in vivo synthesis, urinary excretion or metabolism of different vitamins may be substantially altered in kidney failure. There are discrepancies in vitamin status assessment depending on whether the assay is functional or measuring the blood vitamin level. Whether vitamin supplements should be routinely prescribed for patients with CKD is controversial. Because low dietary intake and compounds that interfere with vitamin activity are not uncommon in patients with CKD, and water-soluble vitamin supplements appear safe and not costly, the authors recommend that supplements of the water-soluble vitamins should be routinely offered to these individuals. More research is needed to assess vitamin nutrition and function and to determine the daily vitamin needs for all patients with CKD.

A Sarcopenia Index Derived from Malnutrition Parameters in Elderly Haemodialysis Patients

(1) Background: Persons with chronic kidney disease may have sarcopenia characterized by the loss of muscle mass and loss of muscle strength. However, EWGSOP2 criteria to diagnose sarcopenia are technically challenging, especially in elderly persons on hemodialysis. Sarcopenia may be associated with malnutrition. We aimed at defining a sarcopenia index derived from malnutrition parameters for use in elderly haemodialysis patients. (2) Methods: A retrospective study of 60 patients aged 75 to 95 years treated with chronic hemodialysis was conducted. Anthropometric and analytical variables, EWGSOP2 sarcopenia criteria and other nutrition-related variables were collected. Binomial logistic regressions were used to define the combination of anthropometric and nutritional parameters that best predict moderate or severe sarcopenia according to EWGSOP2, and performance for moderate and severe sarcopenia was assessed by the area under the curve (AUC) of receiver operating characteristic (ROC) curves. (3) Results: The combination of loss of strength, loss of muscle mass and low physical performance correlated with malnutrition. We developed regression-equation-related nutrition criteria that predicted moderate sarcopenia (elderly hemodialysis sarcopenia index-moderate, EHSI-M) and severe sarcopenia (EHSI-S) diagnosed according to EWGSOP2 with an AUC of 0.80 and 0.866, respectively. (4) Conclusions: There is a close relationship between nutrition and sarcopenia. The EHSI may identify EWGSOP2-diagnosed sarcopenia from easily accessible anthropometric and nutritional parameters.

25-OH vitamin D threshold for optimal bone mineral density in elderly patients with chronic kidney disease

Introduction: Vitamin D deficiency is common in chronic kidney disease (CKD) and is associated with lower bone mineral density (BMD), decreased muscle strength, and increased hip fracture risk. Guidelines have suggested targeting 25-OH vitamin D (25(OH)D) levels between 20 and 30 ng/ml. However, vitamin D metabolism is altered in CKD, and threshold levels for optimal BMD are unknown. Methods: We included 1097 patients with hip fractures. CKD was defined as estimated glomerular filtration rate <60 ml/min/1.73 m (Mucsi et al., Clin. Nephrol., 2005, 64(4), 288-294) and low BMD defined as T score ≤ -2.5 at femoral neck. We assessed the association of 25(OH)D with low BMD in patients with and without CKD: using the conventional threshold 25(OH)D < 30 ng/dl, as well as a new threshold. Results: CKD was present in 479 (44%) patients. Using a threshold of 25(OH)D < 30 ng/ml, there were no significant differences in patients with CKD and low BMD when compared to the other groups. We identified 27 ng/ml as a better threshold with the Youden index. Using 25(OH)D < 27 ng/ml as a threshold, 360 of 482 patients (74.7%) with low 25(OH)D had low BMD, compared to only 185/276 (67%) of patients with adequate vitamin D, p = 0.02, which was irrespective of the presence or absence of CKD. Furthermore, patients with CKD and 25(OH)D < 27 ng/ml had a higher odds ratio of mortality upon follow-up, 1.61, 95% CI: 1.08-2.39, compared to those with CKD and 25(OH)D ≥ 27 ng/ml. Conclusion: We find that 25(OH)D < 27 ng/ml is associated with low BMD in patients with and without CKD. Further prospective studies targeting vitamin D repletion to at least 27 ng/ml and the outcome of hip fractures will be useful to validate these findings.

Muscle Wasting in Chronic Kidney Disease: Mechanism and Clinical Implications—A Narrative Review

Muscle wasting, known to develop in patients with chronic kidney disease (CKD), is a deleterious consequence of numerous complications associated with deteriorated renal function. Muscle wasting in CKD mainly involves dysregulated muscle protein metabolism and impaired muscle cell regeneration. In this narrative review, we discuss the cardinal role of the insulin-like growth factor 1 and myostatin signaling pathways, which have been extensively investigated using animal and human studies, as well as the emerging concepts in microRNA- and gut microbiota-mediated regulation of muscle mass and myogenesis. To ameliorate muscle loss, therapeutic strategies, including nutritional support, exercise programs, pharmacological interventions, and physical modalities, are being increasingly developed based on advances in understanding its underlying pathophysiology.

Unraveling the Metabolic Hallmarks for the Optimization of Protein Intake in Pre-Dialysis Chronic Kidney Disease Patients

The daily amount and quality of protein that should be administered by enteral nutrition in pre-dialysis chronic kidney disease (CKD) patients is a widely studied but still controversial issue. This is due to a compromise between the protein necessary to maintain muscular proteostasis avoiding sarcopenia, and the minimal amount required to prevent uremia and the accumulation of nitrogenous toxic substances in blood because of the renal function limitations. This review underlines some intracellular and extracellular features that should be considered to reconcile those two opposite factors. On one hand, the physiological conditions and usual side effects associated with CKD, mTOR and other proteins and nutrients involved in the regulation of protein synthesis in the muscular tissue are discussed. On the other hand, the main digestive features of the most common proteins used for enteral nutrition formulation (i.e., whey, casein and soy protein) are highlighted, due to the importance of supplying key amino acids to serum and tissues to maintain their concentration above the anabolic threshold needed for active protein synthesis, thereby minimizing the catabolic pathways leading to urea formation.

Low serum 1,25(OH)2D3 in end-stage renal disease: is reduced 1α-hydroxylase the only problem?

Low serum 1,25-dihydroxyvitamin D (1,25(OH)2D) in end-stage renal disease (ESRD) is considered a consequence of elevated fibroblast growth factor 23 (FGF23) and concomitant reduced activity of renal 1α-hydroxylase (CYP27B1). Current ESRD treatment strategies to increase serum calcium and suppress secondary hyperparathyroidism involve supplementation with vitamin D analogues that circumvent 1α-hydroxylase. This overlooks the potential importance of 25-hydroxyvitamin D (25(OH)D) deficiency as a contributor to low serum 1,25(OH)2D. We investigated the effects of vitamin D (cholecalciferol) supplementation (40,000 IU for 12 weeks and maintenance dose of 20,000 IU fortnightly), on multiple serum vitamin D metabolites (25(OH)D, 1,25(OH)2D3 and 24,25(OH)2D3) in 55 haemodialysis patients. Baseline and 12 month data were compared using related-samples Wilcoxon signed rank test. All patients remained on active vitamin D analogues as part of routine ESRD care. 1,25(OH)2D3 levels were low at baseline (normal range: 60-120 pmol/L). Cholecalciferol supplementation normalised both serum 25(OH)D and 1,25(OH)2D3. Median serum 25(OH)D increased from 35.1 nmol/L (IQR: 23.0-47.5 nmol/L) to 119.9 nmol/L (IQR: 99.5-143.3 nmol/L) (P < 0.001). Median serum 1,25(OH)2D3 and 24,25(OH)2D3 increased from 48.3 pmol/L (IQR: 35.9-57.9 pmol/L) and 3.8 nmol/L (IQR: 2.3-6.0 nmol/L) to 96.2 pmol/L (IQR: 77.1-130.6 pmol/L) and 12.3 nmol/L (IQR: 9-16.4 nmol/L), respectively (P < 0.001). A non-significant reduction in daily active vitamin D analogue dose occurred, 0.94 µmcg at baseline to 0.77 µmcg at 12 months (P = 0.73). The ability to synthesise 1,25(OH)2D3 in ESRD is maintained but is substrate dependent, and serum 25(OH)D was a limiting factor at baseline. Therefore, 1,25(OH)2D3 deficiency in ESRD is partly a consequence of 25(OH)D deficiency, rather than solely due to reduced 1α-hydroxylase activity as suggested by current treatment strategies.

A review and perspective on the assessment, management and prevention of fragility fractures in patients with osteoporosis and chronic kidney disease

This article aims to review the methods used for the assessment of fracture risk and the use of osteoporosis medications for fracture prevention in the population with CKD, and highlights the difficulties faced by clinicians in the management of these patients and the latest recommendations and guidelines. Chronic kidney disease (CKD) and osteoporosis often co-exist in older adults, and they present a major healthcare challenge. CKD mineral and bone disorder (CKD-MBD) occurs as renal function declines and this syndrome affects most patients in CKD stages 4 and 5. The biochemical abnormalities of CKD-MBD, renal bone disease and risk factors associated with age-related bone loss and osteoporosis lead to a cumulative effect on fracture risk and mortality. There is a need for routine evaluation of fracture risk and fracture prevention in this population. Measurement of bone mineral density (BMD) and the use of the FRAX tool have predictive value for incident fractures in the general population and in CKD. This enables physicians to identify CKD patients most at risk of sustaining a fragility fracture and allows a more targeted approach to fracture prevention. Data analysis from the pivotal trials of therapeutic agents used in osteoporosis show that these drugs can be considered in mild and moderate CKD (stages 1-3 CKD). Off-label drug use in patients with CKD-MBD and more severe renal impairment (CKD stages 4 and 5) could offer significant benefits to sub-groups of patients when carefully tailored to each individual's bone turnover and calcium and phosphate balance. However, this requires a selective approach and treatment decisions based on inference from pathophysiology while we await further trials. Guidelines advocate the correction and/or reduction of the biochemical abnormalities of CKD-MBD before initiation of treatment with osteoporosis drugs and close monitoring during treatment.

Welfare receipt and the risk of vitamin D deficiency in Japanese patients on maintenance hemodialysis: a cross-sectional, retrospective study

BACKGROUND

Vitamin D deficiency is often observed in patients undergoing maintenance hemodialysis and is associated with significantly increased risk of overall mortality. Despite reports of poor nutrition/intake, vitamin D status among patients on maintenance hemodialysis receiving welfare remains unknown. This study investigated the vitamin D status in welfare recipients undergoing maintenance hemodialysis.

METHODS

This cross-sectional study investigated vitamin D status among 106 outpatients undergoing maintenance hemodialysis at two medical facilities in Japan. Patients were divided into welfare and non-welfare groups based on their status as of September 2018. Patients were divided into two categories: serum vitamin D deficiency, defined as serum 25(OH)D concentrations < 12 ng/mL, or non-deficiency. Vitamin D deficiency was used as a dependent variable, while welfare receipt was used as the main predictor variable.

RESULTS

Mean [± standard deviation] patient age, median [interquartile range] body mass index, and hemodialysis duration were 66.9 [± 10.8] years, 21.5 [19.6, 24.3] kg/m2, and 7.9 [2.9, 12.3] years, respectively. Among 106 patients, 45 were women (42.5%) and 16 (15.1%) were receiving welfare. The welfare group had a higher diabetes prevalence (P = 0.003) and significantly lower median serum 25-hydroxyvitamin D concentrations (11.5 [8.7, 14.0] vs. 14.8 [11.2, 19.9] ng/mL, P = 0.005). Multiple logistic regression analysis revealed that welfare receipt was a significant risk factor for vitamin D deficiency (odds ratio [95% confidence interval], 4.41 [1.08, 18.07]).

CONCLUSIONS

Welfare recipients undergoing maintenance hemodialysis are at significantly increased risks of vitamin D deficiency compared with patients not receiving welfare.

Association between vitamin D deficiency and exercise capacity in patients with CKD, a cross-sectional analysis

BACKGROUND

Evidence is growing for a role of vitamin D in regulating skeletal muscle mass, strength and functional capacity. Given the role the kidneys play in activating total vitamin D, and the high prevalence of vitamin D deficiency in Chronic Kidney Disease (CKD), it is possible that deficiency contributes to the low levels of physical function and muscle mass in these patients.

METHODS

This is a secondary cross-sectional analysis of previously published interventional study, with in vitro follow up work. 34 CKD patients at stages G3b-5 (eGFR 25.5 ± 8.3 mL/min/1.73m2; age 61 ± 12 years) were recruited, with a sub-group (n = 20) also donating a muscle biopsy. Vitamin D and associated metabolites were analysed in plasma by liquid chromatography tandem-mass spectroscopy and correlated to a range of physiological tests of muscle size, function, exercise capacity and body composition. The effects of 1α,25(OH)2D3 supplementation on myogenesis and myotube size was investigated in primary skeletal muscle cells from vitamin D deficient donors.

RESULTS

In vivo, there was no association between total or active vitamin D and muscle size or strength, but a significant correlation with V̇O_2Peak was seen with total vitamin D (25OHD). in vitro, 1α,25(OH)₂D3 supplementation reduced IL-6 mRNA expression, but had no effect upon proliferation, differentiation or myotube diameter.

CONCLUSIONS

Vitamin D deficiency is not a prominent factor driving the loss of muscle mass in CKD, but may play a role in reduced exercise capacity.

VITADIAL "Does correction of 25 OH-VITAmin D with cholecalciferol supplementation increase muscle strength in hemoDIALysis patients?": study protocol for a randomized controlled trial

BACKGROUND

Muscle strength decreases as kidney failure progresses. Low muscle strength affects more than 50% of hemodialysis patients and leads to daily life activities impairment. In the general population, numerous studies have linked low 25OH-vitamin D (25OHD) concentrations to the loss of the muscle strength and low physical performances. Data on native vitamin D and muscle function are scarce in the chronic kidney disease (CKD) population, but low 25OHD levels have been associated with poor muscle strength. We present in this article the protocol of an ongoing study named VITADIAL testing if cholecalciferol supplementation in hemodialysis patients with low 25OHD improves their muscle strength.

METHODS/DESIGN

VITADIAL is a prospective open randomized French multicenter study. All patients will have 25OHD levels ≤50nmol/L at randomization. One group will receive 100,000 UI cholecalciferol once a month during 6 months; the other group will receive no treatment during 6 months. In order to randomize patients with 25OHD ≤50nmol/L, supplemented patients will undergo a 3 months wash-out period renewable 3 times (maximum of 12 months wash-out) until 25OHD reaches a level ≤50nmol/L. The main objective of this study is to analyze if a 6-month period of oral cholecalciferol (i.e., native vitamin D) supplementation improves muscle strength of hemodialysis patients with low 25OHD vitamin D levels. Muscle strength will be assessed at 0, 3, and 6 months, by handgrip strength measured with a quantitative dynamometer. Secondary objectives are (1) to analyze 25OHD plasma levels after vitamin D wash-out and/or supplementation, as well as factors associated with 25OHD lowering speed during wash-out, and (2) to analyze if this supplementation improves patient's autonomy, reduces frailty risk, and improves quality of life. Fifty-four patients are needed in each group to meet our main objective.

DISCUSSION

In the general population, around 30 randomized studies analyzed the effects of vitamin D supplementation on muscle strength. These studies had very different designs, sizes, and studied population. Globally, these studies and the meta-analysis of studies favor a beneficial effect of vitamin D supplementation on muscle strength, but this effect is mainly found in the subgroup of aged patients and those with the lowest 25OHD concentrations at inclusion. We reported a positive independent association between 25OHD and handgrip strength in a population of 130 hemodialysis patients in a dose-dependent manner. In our cohort, a plateau effect was observed above 75 nmol/L. Only two randomized studies analyzed the effect of native vitamin D supplementation on muscle strength in hemodialysis patients, but unfortunately, these two studies were underpowered. VITADIAL is a trial specifically designed to assess whether cholecalciferol might benefit to hemodialysis patient's muscle strength.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04262934 . Registered on 10 February 2020 - Retrospectively registered.

Risk factors for high fall risk in elderly patients with chronic kidney disease

PURPOSE

Patients with chronic kidney disease (CKD) usually represent an aging population, and both older age and CKD are associated with a higher risk of falling. Studies on risk factors among subjects with CKD are lacking.

METHODS

Records of outpatients from one geriatric clinic in Turkey were retrospectively reviewed. A result of ≥ 13.5 s on the timed up and go (TUG) test was accepted as a high risk of falls. Independent predictors of an increased risk of falls among subjects with CKD (estimated glomerular filtration rate of < 60 mL/min/1.73 m²) were identified using logistic regression models.

RESULTS

Patients with CKD (n = 205), represented the 20.2% of the entire cohort and was identified as an independent predictor of increased fall risk (OR 2.59). Within the CKD cohort, serum folic acid levels and frailty were independent predictors of an increased risk of falls. The CKD/fall risk group was older, had a lower median years of education, lower vitamin D levels, and lower serum folic acid levels than the CKD/non-fall risk group. In addition to higher serum creatinine and potassium levels, the only significant difference between patients with CKD/fall risk and a matched non-CKD/fall risk was a lower median folic acid level in the former group.

CONCLUSIONS

Frailty and low folic acid levels are independently associated with an increased risk of falls among elderly outpatients with CKD. Prevention of frailty may reduce the risk of falls in these subjects. Possible benefit of folic acid supplementation requires further studies.

Relation of Serum 25-Hydroxyvitamin D Status with Skeletal Muscle Mass and Grip Strength in Patients on Peritoneal Dialysis

The aim of this study was to investigate the association of serum 25-hydroxyvitamin D (25(OH)D) with skeletal muscle mass (SMM) and grip strength in patients on peritoneal dialysis. In this single center retrospective study, a total of 113 incident peritoneal dialysis patients (65 men, 48 women) were included. Serum concentrations of 25(OH)D were measured through radioimmunoassay. Hypovitaminosis was classified when the level of serum 25(OH)D was <20 ng/mL. SMM was assessed through bioelectrical impendence analysis, whereas grip strength was assessed through handgrip dynamometer. On the basis of expert consensus of the Asian Working Group for Sarcopenia, low muscle mass was defined as relative skeletal mass index (RSMI)<7.0 kg/m² for men and <5.7 kg/m² for women. The general linear and noncondition logistical regression model were employed to explore the association between vitamin D and both muscle mass and grip strength. The mean serum 25(OH)D level was 19.3(±8.4) ng/mL. Compared with 25(OH)D<20 ng/mL, the mean values of SMM, appendicular skeletal muscle mass (ASM), ASMI, and grip strength were higher for ≥20 ng/mL. Subjects (25(OH)D<20 ng/mL) had a greater proportion of low SMM (55.8%) and low grip strength (66.4%). After adjusting for multiple factors, serum 25(OH)D was positively associated with grip strength (β=0.18, p=0.009), ASM (β=0.14, p<0.001), and RSMI (β=0.07, p<0.001); 25(OH)D<20 ng/mL was significantly associated with low grip strength (OR=2.97, 95% CI: 1.17-7.55), and low SMM (OR=2.73, 95% CI: 1.15-6.45). The present study demonstrated a positive association between serum vitamin D status and skeletal muscle mass and grip strength in patients on peritoneal dialysis.

Risk factors for decreased upper-limb muscle strength and its impact on survival in maintenance hemodialysis patients

PURPOSE

Protein-energy wasting, characterized by decreased muscle mass, is one of the strongest predictors of mortality in patients on maintenance hemodialysis (MHD). As people get older, their muscle strength usually declines faster than muscle mass. However, the association between lower-limb muscle strength and all-cause mortality remains unclear. We aimed to evaluate risk factors for decreased upper-limb muscle strength in MHD patients and its impact on patient survival.

METHODS

The cross-sectional part of the study included 174 MHD patients. Subsequently, they were followed up for 52 weeks. Biceps muscle strength, anthropometry, body composition, dietary intake, daily steps, and biochemical indicators of malnutrition and inflammation were evaluated. Risk factors for muscle weakness were screened by multiple linear regression analysis, and patient survival was analyzed by Kaplan-Merier and Cox multivariate analysis.

RESULTS

The 174 MHD patients (93 men; 63.05 ± 12.29 years) were classified as a young (< 65 years, n = 97) group and an elderly group (≥ 65 years, n = 77). Gender, daily steps, muscle mass, 25(OH)D level and IL-6 in young group, and muscle mass, 25(OH)D, daily steps, and NT-proBNP in elderly group were associated with the decreased biceps muscle strength. The survival rate in high muscle strength group was significantly higher than that in low muscle strength group (P = 0.002). The association between low muscle strength and high mortality risk remained strong in the fully adjusted model.

CONCLUSION

Risk factors of muscle weakness were different between young and elderly MHD patients. There was a strong correlation between strong biceps muscle strength and high patient survival.

Association between Vitamin D Level and Muscle Strength in Patients Undergoing Hemodialysis

INTRODUCTION

Identification of the risk factors and treatment of the decrease in muscle mass or strength are important to improve the prognosis of patients undergoing hemodialysis (HD). Previous studies have investigated the association between vitamin D level and muscle mass or strength in patients undergoing HD. However, there are conflicting results regarding this association.

OBJECTIVE

To evaluate the association between vitamin D level and muscle mass indices, strength, or physical performance in patients undergoing HD.

METHODS

This study was performed in a tertiary medical center. We included patients undergoing HD aged ≥20 years. A total of 84 patients were enrolled. The patients were divided into tertiles based on the 25-hydroxy (25-OH) vitamin D level as follows: lowest tertile (Lowest T, n = 28), middle tertile (Middle T, n = 28), and highest tertile (Highest T, n = 28). We evaluated the association between the tertiles and clinical outcomes including nutritional status, muscle mass, muscle function, handgrip strength (HGS), physical performance, and health-related quality of life (HRQoL) scales.

RESULTS

There were no significant differences in the muscle mass indices and nutritional markers according to tertiles of 25-OH vitamin D level. However, 25-OH vitamin D level as a continuous variable or the tertile of 25-OH vitamin D level as a categorical variable was positively associated with HGS. Logistic and linear regression analyses showed a consistent superiority of the Highest T in HGS compared with the Lowest or Middle T. Although the statistical significance was weak, the scores of various physical performance tests and the HRQoL scales were highest in the Highest T among the 3 tertiles.

CONCLUSION

The present study demonstrated that serum vitamin D level is associated with HGS in patients undergoing HD regardless of muscle mass indices or nutritional status.

Benefit-risk balance of native vitamin D supplementation in chronic hemodialysis: what can we learn from the major clinical trials and international guidelines?

For some years, there has been a great renewal of interest in native vitamin D and its major involvement in osseous and non-osseous effects in the organism. Patients in chronic hemodialysis (CHD) constitute a specific population with different physiopathologic characteristics and needs, since morbidity and mortality are strongly correlated with vitamin D insufficiency. Vitamin D supplementation raises very pertinent questions for which we have only partial answers and we lack solid scientific proof to establish certain truths. Thus, we try through this mini-review to analyze the results of the main randomized clinical trials conducted during the last decade, and to discuss international guidelines concerning native vitamin D supplementation in CHD patients. Seven double-blind randomized clinical trials have evaluated native Vitamin D supplementation in CHD patients. These clinical trials began between 2007 and 2013 and studied relatively small samples of patients with an average of 50. All of these trials are important, but do not provide sufficient scientific proof concerning the advantages, consequences, and secondary effects of native vitamin D supplementation in CHD. None of the European, American, English, Asian, Australian, or Canadian recommendations have specified the targets, doses, duration, or the molecule of vitamin D supplementation in the patient on CHD. In 2017, the long-awaited KDIGO recommendations were published and despite the results of clinical trials conducted, the recommendations on native vitamin D supplementation in CHD were very imprecise and sparse, limited to suggesting correction of any state of vitamin D insufficiency or deficiency.

Effect of Resistance Exercise Plus Cholecalciferol on Nutritional Status Indicators in Adults With Stage 4 Chronic Kidney Disease

OBJECTIVE

Decreased serum concentrations of 25-hydroxyvitamin D (25(OH)D) affect people with chronic kidney disease (CKD); lower concentrations of 25(OH)D have been associated with decrease in nutritional status indicators. On the other hand, muscle resistance exercise has improved the nutritional status of patients with CKD.The aim of this study was to evaluate the effect of resistance exercise and dietary supplementation with cholecalciferol on nutritional status indicators in adults with stage 4 CKD.

METHODS

Patients with an estimated glomerular filtration rate between 15 and 29 mL/min/1.73 m² in an open-label clinical trial were followed for 12 weeks. The intervention group received exercise resistance training sessions three times per week with oral cholecalciferol supplementation each day. The control group only received standard medical care. The outcomes were anthropometric measurements, handgrip strength, and bioelectrical impedance analysis.

RESULTS

Thirty-nine patients of a median age of 48 (36-52) years had an estimated glomerular filtration rate of 21.8 ± 6.5 mL/min/1.73 m². A total of 57.5% of the patients were women. In 41% of the patients, the etiology of CKD was diabetes. After 12 weeks, in the intervention group, the adherence to the resistance training was 77%, and the adherence to the supplementation with cholecalciferol was 96.2%. Significant improvements in 25(OH)D serum concentrations and in handgrip strength were detected in the intervention group (P < .05). In the control group, a decrease in 25(OH)D serum concentrations and a loss in handgrip strength were observed, although the difference was not statistically significant. Anthropometrics and biochemical and dietary indicators, but not bioelectrical impedance data, exhibited changes.

CONCLUSION

Supplementation with cholecalciferol improves serum concentrations of 25(OH)D and, when combined with resistance exercise, improved muscle function as measured by handgrip strength in a study of patients with CKD not on dialysis.

Sarcopenia and relationships between muscle mass, measured glomerular filtration rate and physical function in patients with chronic kidney disease stages 3-5

Background

Sarcopenia and poor physical function are common in patients with chronic kidney disease (CKD). Our aim was to investigate the relationships between muscle mass and measured glomerular filtration rate (GFR) and between muscle mass and strength and balance, respectively, in patients with CKD stages 3-5.

Methods

This is a baseline data analysis of a randomized controlled clinical trial. A total of 148 adult patients with an estimated GFR <30 mL/min/1.72 m2, not on renal replacement therapy, irrespective of the number of comorbidities were included from the Department of Nephrology, Skåne University Hospital, Lund, from 2011 to 2016. Body composition was measured by dual-energy X-ray absorptiometry (DEXA). GFR was measured by iohexol clearance. Balance was measured by functional reach and the Berg balance test and strength by handgrip strength and isometric quadriceps strength.

Results

Measured GFR ranged from 8 to 55 mL/min/1.73 m2. Lean mass (P < 0.05), fat mass (P < 0.05), appendicular skeletal muscle (P < 0.001) and appendicular skeletal muscle index (P < 0.05) were associated with GFR. Functional reach was associated with leg lean mass (P < 0.05) and the Berg balance test score was associated with trunk lean mass (P < 0.05). Handgrip strength was associated with arm lean mass (P < 0.001). Isometric quadriceps strength was associated with leg lean mass (P < 0.001). More men (44%) suffered from low muscle mass than women (22%), whereas more women (36%) suffered from low muscle strength than men (26%). However, when combining both, men (16%) suffered from sarcopenia to a greater extent than women (8%).

Conclusions

Among patients with CKD stages 3-5, loss of lean body mass, especially appendicular skeletal muscle, was significantly related to GFR decline. Two important markers of physical function, balance and strength, were significantly related to muscle mass. Moreover, men were more prone to sarcopenia than women during kidney function decline.

The use of LP533401 as a therapeutic option for renal osteodystrophy affects, renal calcium handling, vitamin D metabolism, and bone health in uremic rats

BACKGROUND

Klotho is a key regulator of phosphate and Ca²⁺-transport in the kidney. Recently, we showed that treatment with LP533401 improved bone health in rats with chronic kidney disease (CKD) via the normalization of serum phosphate resulting from the reduced renal expression of phosphate cotransporters, including Klotho.

METHODS

We evaluated the effect of LP533401 therapy on Klotho-expression-dependent Ca²⁺-transporters, renal calcium handling, and the potential consequences for the bone of uremic rats.

RESULTS

Treatment with LP533401 and its vehicle resulted in the inhibition of transient receptor potential vanilloid receptor subtypes 5 and 6 (TRPV5, TRPV6) and calbindin (CaBP-28k, CaBP-9k) expression. The compensatory acceleration in renal expression of Na+/Ca²⁺-exchanger, 25-hydroxyvitamin d-1α-hydroxylase (CYP27B1), the intensification of vitamin D metabolism, and disruption of sophisticated balance between 1,25-dihydroxyvitamin D-serotonin was observed, especially in rats treated with LP533401. The imbalance between 1,25-dihydroxyvitamin D-serotonin levels led to intensified bone remodeling and improvement in bone geometry, mineral status, and strength in animals treated with LP533401.

CONCLUSION

The modulation of circulating serotonin and its relation to other regulators of calcium handling can play an important role in calcium homeostasis and bone integrity in CKD rats treated with LP533401.

Mineral bone disorders in chronic kidney disease

As the GFR loss aggravates, the disturbed mineral metabolism worsens the bone microstructure and remodelling - scenario, which is known as CKD-mineral bone disease (MBD). CKD-MBD is characterized by : (i) abnormal metabolism of calcium, phosphorus, parathyroid hormone (PTH), or vitamin D; (ii) abnormalities in bone turnover, mineralization, volume linear growth or strength; (iii) soft-tissue calcifications, either vascular or extra-osseous. Uremic vascular calcification and osteoporosis are the most common complications related to CKD-MBD. Disregulated bone turnover by uremic toxin or secondary hyperparathyroidism disturbed bone mineralization and makes it difficult for calcium and inorganic phosphate to enter into bone, resulting in increased serum calcium and inorganic phosphate. Vascular calcification worsens by hyperphosphatemia and systemic inflammation. Since vitamin D deficiency plays an important role in renal osteodystrophy, supplement of nutritional vitamin D is important in treating uremic osteoporosis and vascular calcification at the same time. Its pleotropic effect improves the bone remodeling initiated by osteoblast and alleviates the risk factors for vascular calcification with less hypercalcemia than vitamin D receptor analogs. Therefore, nutritional vitamin D should be considered in managing CKDMBD.

The Likelihood of Self-reporting Balance Problems in Those With Advanced Chronic Kidney Disease, Slow Gait Speed, or Low Vitamin D

OBJECTIVE

The purpose of this study was to determine the prevalence of vitamin D (25(OH)D) and balance deficits in persons with chronic kidney disease (CKD) and the likelihood of self-reporting balance and falling problems, measured gait speed in persons with kidney disease, and low levels of vitamin D and albumin.

DESIGN

Analysis of the National Health and Nutrition Examination Survey 1999-2004 data set.

SUBJECTS

The study included 8,554 subjects aged >40 years who were categorized into CKD stages based on the glomerular filtration rate (normal kidney function and stages 1 and 2 served as the control group, and stages 3 and 4/5 served as the CKD groups).

MAIN OUTCOME MEASURES

Measured 25(OH)D levels, timed 20-feet walk, Romberg standing balance task, and self-reported balance and falling issues.

RESULTS

The prevalence of balance deficits was found to be high in this CKD sample, with fail rates increasing with kidney disease severity. Similarly, when examining the relationship between CKD stage and the measurement of balance, fail rates (impaired balance) increased and gait speed decreased with kidney disease severity. In addition, the likelihood of self-reporting a balance and falling problem in the past year was higher in persons who had advanced CKD, were of older age, were of female sex, were with former or current smoking status, had lower 25(OH)D levels, and had lower albumin levels. Similarly, the likelihood of having a 20-feet walk time of more than 8 seconds was associated with those who were older, had higher body mass index, and had lower levels of 25(OH)D and albumin.

CONCLUSION

The unique finding of this study is that increased reporting of balance and falling issues (both perceived and measured) and slower gait were found in persons with increased CKD severity and lower 25(OH)D status.

Vitamin D Deficiency in Chronic Kidney Disease: Recent Evidence and Controversies

Vitamin D (VD) is a pro-hormone essential for life in higher animals. It is present in few types of foods and is produced endogenously in the skin by a photochemical reaction. The final step of VD activation occurs in the kidneys involving a second hydroxylation reaction to generate the biologically active metabolite 1,25(OH)₂-VD. Extrarenal 1α-hydroxylation has also been described to have an important role in autocrine and paracrine signaling. Vitamin D deficiency (VDD) has been in the spotlight as a major public healthcare issue with an estimated prevalence of more than a billion people worldwide. Among individuals with chronic kidney disease (CKD), VDD prevalence has been reported to be as high as 80%. Classically, VD plays a pivotal role in calcium and phosphorus homeostasis. Nevertheless, there is a growing body of evidence supporting the importance of VD in many vital non-skeletal biological processes such as endothelial function, renin-angiotensin-aldosterone system modulation, redox balance and innate and adaptive immunity. In individuals with CKD, VDD has been associated with albuminuria, faster progression of kidney disease and increased all-cause mortality. Recent guidelines support VD supplementation in CKD based on extrapolation from cohorts conducted in the general population. In this review, we discuss new insights on the multifactorial pathophysiology of VDD in CKD as well as how it may negatively modulate different organs and systems. We also critically review the latest evidence and controversies of VD monitoring and supplementation in CKD patients.

Factors associated with falls in older adults with cancer: a validated model from the Cancer and Aging Research Group

BACKGROUND

Falls in older adults with cancer are common, yet factors associated with fall-risk are not well-defined and may differ from the general geriatric population. This study aims to develop and validate a model of factors associated with prior falls among older adults with cancer.

METHODS

In this cross-sectional secondary analysis, two cohorts of patients aged ≥ 65 with cancer were examined to develop and validate a model of factors associated with falls in the prior 6 months. Potential independent variables, including demographic and laboratory data and a geriatric assessment (encompassing comorbidities, functional status, physical performance, medications, and psychosocial status), were identified. A multivariate model was developed in the derivation cohort using an exhaustive modeling approach. The model selected for validation offered a low Akaike Information Criteria value and included dichotomized variables for ease of clinical use. This model was then applied in the validation cohort.

RESULTS

The development cohort (N = 498) had a mean age of 73 (range 65-91). Nearly one-fifth (18.2%) reported a fall in the prior 6 months. The selected model comprised nine variables involving functional status, objective physical performance, depression, medications, and renal function. The AUC of the model was 0.72 (95% confidence intervals 0.65-0.78). In the validation cohort (N = 250), the prevalence of prior falls was 23.6%. The AUC of the model in the validation cohort was 0.62 (95% confidence intervals 0.51-0.71).

CONCLUSION

In this study, we developed and validated a model of factors associated with prior falls in older adults with cancer. Future study is needed to examine the utility of such a model in prospectively predicting incident falls.

Glucocorticoid-Induced Myopathy in a Patient with Systemic Lupus Erythematosus (SLE): A Case Report and Review of the Literature

Patient: Female, 35

Final Diagnosis: Glucocorticoid-induced myopathy

Symptoms: Generalized weakness

Medication: Prednisone

Clinical Procedure: —

Specialty: General and Internal Medicine

Whole body vibration improves maximum voluntary isometric contraction of knee extensors in patients with chronic kidney disease: A randomized controlled trial

BACKGROUND

Whole body vibration (WBV) training improves maximum voluntary isometric contraction (MVIC) of knee extensors, postural balance, functional capacity, and quality of life (QOL) in several diseases. The objective was to assess the efficacy of WBV training in patients with chronic kidney disease (CKD) on hemodialysis (HD) in the interdialytic period.

METHOD

A randomized, controlled trial study with concealed allocation, intention-to-treat analysis, and triple blinding. Sixteen patients with CKD of both genders aged over 40 years were allocated in two groups, the WBV group or the sham group, training 2 times a week for 12 weeks. The primary outcome was knee extensor muscle strength, and the secondary outcomes were quadriceps thickness, distance walked, balance, and QOL.

RESULTS

The WBV group improved MVIC of knee extensors with a difference between groups in improvement of 117.29 N (95% CI, 32.25-202.24) at the end of training. The other outcomes were not different between groups. Practical applications: The WBV program has shown to be effective and may be able to help in prescribing the appropriate training program for CKD.

CONCLUSION

WBV training improves MVIC of knee extensors in patients with CKD on HD in the interdialytic period. WBV training could be considered in the management of patients with CKD.

Non-musculoskeletal benefits of vitamin D

The aim of this study is to determine and critically evaluate the plausible relationships of vitamin D with extra-skeletal tissues in humans. Severe vitamin D deficiency results in rickets in children and osteomalacia in adults; these beneficial effects in the musculoskeletal system and certain physiological functions are well understood. Nevertheless, mounting reports support additional beneficial effects of vitamin D, outside the musculoskeletal system. This review explores the recent advances in knowledge about the non-skeletal effects of vitamin D. Peer-reviewed papers were extracted from research databases using key words, to assess correlations between vitamin D and extra-skeletal diseases and conditions. As per the guidelines of the Preferred Reporting Items for Systematic Reviews (PRISMA); general interpretations of results are included; taking into consideration the broader evidence and implications. This review summarizes current knowledge of the effects of vitamin D status on extra-skeletal tissues with special attention given to relationships between vitamin D status and various diseases commonly affecting adults; the effects of intervention with vitamin D and exposure to sunlight. Evidence suggests that vitamin D facilitates the regulation of blood pressure; and cardiac; endothelial; and smooth muscle cell functions; playing an important role in cardiovascular protection. In addition; 1,25(OH)₂D improves immunity; subdues inflammation; and reduces the incidence and severity of common cancers; autoimmune diseases and infectious diseases. Almost all adequately powered; epidemiological and biological studies that use; adequate doses of vitamin D supplementation in D-deficient populations have reported favorable outcomes. These studies have concluded that optimizing 25(OH)D status improves the functionality of bodily systems; reduces comorbidities; improves the quality of life; and increases survival. Although accumulating evidence supports biological associations of vitamin D sufficiency with improved physical and mental functions; no definitive evidence exists from well-designed; statistically powered; randomized controlled clinical trials. Nevertheless, most studies point to significant protective effects of vitamin D in humans when the minimum 25(OH)D serum level exceeds 30ng/mL and is maintained throughout the year.

Vitamin D in Chronic Kidney Disease and Dialysis Patients

Vitamin D deficiency (<20 ng/mL) and insufficiency (20–29 ng/mL) are common among patients with chronic kidney disease (CKD) or undergoing dialysis. In addition to nutritional and sunlight exposure deficits, factors that affect vitamin D deficiency include race, sex, age, obesity and impaired vitamin D synthesis and metabolism. Serum 1,25(OH)₂D levels also decrease progressively because of 25(OH)D deficiency, together with impaired availability of 25(OH)D by renal proximal tubular cells, high fibroblast growth factor (FGF)-23 and decreased functional renal tissue. As in the general population, this condition is associated with increased morbidity and poor outcomes. Together with the progressive decline of serum calcitriol, vitamin D deficiency leads to secondary hyperparathyroidism (SHPT) and its complications, tertiary hyperparathyroidism and hypercalcemia, which require surgical parathyroidectomy or calcimimetics. Kidney Disease Outcomes Quality Initiative (KDOQI) and Kidney Disease Improving Global Outcomes (KDIGO) experts have recognized that vitamin D insufficiency and deficiency should be avoided in CKD and dialysis patients by using supplementation to prevent SHPT. Many vitamin D supplementation regimens using either ergocalciferol or cholecalciferol daily, weekly or monthly have been reported. The benefit of native vitamin D supplementation remains debatable because observational studies suggest that vitamin D receptor activator (VDRA) use is associated with better outcomes and it is more efficient for decreasing the serum parathormone (PTH) levels. Vitamin D has pleiotropic effects on the immune, cardiovascular and neurological systems and on antineoplastic activity. Extra-renal organs possess the enzymatic capacity to convert 25(OH)D to 1,25(OH)₂D. Despite many unanswered questions, much data support vitamin D use in renal patients. This article emphasizes the role of native vitamin D replacement during all-phases of CKD together with VDRA when SHPT persists.

Evaluating the fall risk among elderly population by choice step reaction test

Falls during daily activities are often associated with injuries and physical disabilities, thereby affecting quality of life among elder adults. Balance control, which is crucial in avoiding falls, is composed of two elements: muscle strength and central nervous system (CNS) control. A number of studies have reported that reduced muscle strength raises the risk of falling. However, to date there has been only limited research focused on the relationship between fall risk and the CNS. This study aimed to investigate the relationship between CNS and risk of falling among the elderly. A total of 140 elderly people (92 females and 48 males) were divided into faller and nonfaller groups based on questionnaire responses concerning falls in their daily life. Participants undertook a choice step reaction test in which they were required to respond to random visual stimuli using foot movements as fast as possible in the left or right directions. Response time was quantified as premotor time (PMT) and motor time (MT). In addition, the participants’ electro-myography data were recorded during the choice step reaction test. A maximal isokinetic torque test was also performed. PMT was greater in the fallers than in the nonfallers group. There was a significant difference between fall status and direction on PMT. PMT of the left limb in nonfallers was faster than the right, but in fallers there was no difference between left and right limbs. A similar phenomenon was also observed for MT. There were significant differences between fallers and nonfallers in maximum isokinetic torque at knee and ankle joints. The correct rate of PMT was higher than other variables, such as MT and maximal isokinetic torque, in evaluating elderly fall risk by using logistic regression analyses. The results suggest that PMT in the choice step reaction test could be a useful parameter to assess risk of fall among elder adults. In addition, decreased maximal isokinetic torque was related to greater PMT and disappearance of asymmetry in older adults who were at higher risk of fall, especially in the lower limb.

Ageing Renal Patients: We Need More Collaboration between Geriatric Services and Nephrology Departments

There has been a significant increase in the number of frail older patients diagnosed with advanced chronic kidney disease (CKD) over the past thirty years. These elderly patients have high levels of comorbidity, and as a consequence the face of renal medicine is changing—There is an increasing need to focus on traditionally geriatric areas of expertise such as falls prevention and rehabilitation, and to shift our emphasis onto improving patient well-being rather than longevity. Over the past decade, many nephrologists have found that they are already acting as de facto “amateur geriatricians”. This denies patients both the benefits of specialist geriatric assessment, and equally importantly denies them access to the wider geriatric multidisciplinary team. This article describes the prevalence and underlying causes of the so-called “Geriatric Giants” in patients with advanced CKD, and discusses possible improvements in care that closer working with geriatricians could bring.

Renal disease and accidental falls: a review of published evidence

BACKGROUND

The pathogenesis of falling is complex, and identification of risk factors may be essential for prevention. The relationship between renal disease and falls is unclear, and the goal of this study was to collect the available evidence and investigate the relationship between accidental falls and renal dysfunction.

METHODS

Electronic searches were performed in the MEDLINE, Scopus, Ovid SP and Web of Science databases to identify the appropriate literature. The themes used were: falls (combined in the title/abstract fall or falls or falling or faller* or fallen or slip* or trip* or (MeSH) accidental falls) and renal insufficiency (chronic or renal insufficiency or kidney diseases combined in title/abstract renal disease* or kidney disease* or renal insufficiency or kidney insufficiency or kidney failure or renal failure or MeSH renal insufficiency, chronic or renal insufficiency or kidney diseases). The incidence, risk factors, complications, and characteristics of the falls were analyzed.

RESULTS

Eight prospective cohorts including five cross-sectional studies, and one case-control study were identified. No randomized controlled studies were found. The incidence of falls in chronic kidney disease patients ranged between 1.18 and 1.60 fall/patient year. These were frequent in frail older adults on hemodialysis treatment. Falling relapses in the same group of patients caused serious consequences. Data on pre-end stage renal disease (ESRD) were scarce.

CONCLUSIONS

The risk of falling appears to be common in patients with renal dysfunction especially in older adults undergoing hemodialysis. On the other hand, we could not find any conclusive data on pre-ESRD patients.

The "Dose-Effect" Relationship Between 25-Hydroxyvitamin D and Muscle Strength in Hemodialysis Patients Favors a Normal Threshold of 30 ng/mL for Plasma 25-Hydroxyvitamin D

OBJECTIVE

Muscle strength is weakened in maintenance hemodialysis patients. Strength is both a measure of a functional parameter and of frailty as it is independently associated with mortality. In the general population, observational studies show that plasma 25-hydroxyvitamin D (25[OH]D) is positively correlated with muscle strength and function. We analyzed the determinants of muscle strength measured by handgrip and 25(OH)D in a maintenance hemodialysis population.

METHODS

In this observational cross-sectional study, data from all hemodialysis patients from our nephrology department were recorded in July 2014. Daily nutritional oral intake, handgrip strength, body composition measured by bioimpedancemetry analysis, as well as biological and dialysis parameters, were obtained from medical files. We used a linear regression model to assess nutritional, biological, and dialysis parameters as well as body composition associated with handgrip strength.

RESULTS

The median age (interquartile range) of the 130 included patients was 77.3 (69.5-84.7) years, 57.7% were men, and 50.8% had diabetes mellitus. Median handgrip strength value (interquartile range) was 14.3 (10.6-22.2) kg. In univariate analyses, the factors associated with handgrip strength were age, gender, albumin, transthyretin, predialysis creatinine and urea, normalized protein nitrogen appearance, lean mass, and muscle mass measured by bioimpedancemetry analysis as well as phase angle, and 25(OH)D. In multivariate analyses, lower age, male gender, higher albumin, higher muscle mass, and 25(OH)D level ≥ 30 ng/mL were independently correlated with muscle strength measured by handgrip.

CONCLUSIONS

This study found a positive correlation between plasma 25(OH)D and muscle strength measured by handgrip in hemodialysis patients. We report a "dose-effect" relationship between 25(OH)D and handgrip strength under 30 ng/mL, which is no more present above 30 ng/mL. Prospective randomized studies are needed to prove that supplementation with cholecalciferol, leading to 25(OH)D levels ≥ 30 ng/mL, improves muscle strength in hemodialysis patients.

Prevalence and prognostic implications of vitamin D deficiency in chronic kidney disease

Vitamin D is an important nutrient involved in bone mineral metabolism, and vitamin D status is reflected by serum total 25-hydroxyvitamin D (25[OH]D) concentrations. Vitamin D deficiency is highly prevalent in patients with chronic kidney disease (CKD), and nutritional vitamin D supplementation decreases elevated parathyroid hormone concentrations in subgroups of these patients. Furthermore, vitamin D is supposed to have pleiotropic effects on various diseases such as cardiovascular diseases, malignancies, infectious diseases, diabetes, and autoimmune diseases. Indeed, there is cumulative evidence showing the associations of low vitamin D with the development and progression of CKD, cardiovascular complication, and high mortality. Recently, genetic polymorphisms in vitamin D-binding protein have received great attention because they largely affect bioavailable 25(OH)D concentrations. This finding suggests that the serum total 25(OH)D concentrations would not be comparable among different gene polymorphisms and thus may be inappropriate as an index of vitamin D status. This finding may refute the conventional definition of vitamin D status based solely on serum total 25(OH)D concentrations.

Biochemical parameters after cholecalciferol repletion in hemodialysis: results From the VitaDial randomized trial

BACKGROUND

The 2009 KDIGO (Kidney Disease: Improving Global Outcomes) chronic kidney disease-mineral and bone disorder clinical practice guideline suggests correcting 25-hydroxyvitamin D3 (25[OH]D) levels<30ng/mL in patients treated with maintenance hemodialysis, but does not provide a specific treatment protocol.

STUDY DESIGN

2-center, double-blind, randomized, 13-week, controlled trial followed by a 26-week open-label study.

SETTING & PARTICIPANTS

55 adult maintenance hemodialysis patients with 25(OH)D levels<30ng/mL were recruited from June 2008 through October 2009.

INTERVENTION

Cholecalciferol, 25,000IU, per week orally versus placebo for 13 weeks, then 26 weeks of individualized cholecalciferol prescription based on NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) guidelines.

OUTCOMES

Primary end point was the percentage of patients with 25(OH)D levels≥30ng/mL at 13 weeks. Secondary outcomes included the percentage of patients with normal calcium, phosphorus, and intact parathyroid hormone (iPTH) blood levels. Safety measures included incidence of hypercalcemia and hypervitaminosis D.

MEASUREMENTS

Blood calcium and phosphate were measured weekly; iPTH, 25(OH)D, 1,25-dihydroxyvitamin D3 (1,25[OH]2D), and bone turnover markers, trimonthly; fetuin A and fibroblast growth factor 23 (FGF-23) serum levels and aortic calcification scores were determined at weeks 0 and 39.

RESULTS

The primary end point significantly increased in the treatment group compared with the placebo group (61.5% vs 7.4%; P<0.001), as well as 1,25(OH)2D levels (22.5 [IQR, 15-26] vs 11 [IQR, 10-15]pg/mL; P<0.001) and the proportion of patients achieving the target calcium level (76.9% vs 48.2%; P=0.03). Incidence of hypercalcemia and phosphate and iPTH levels were similar between groups. The second 26-week study phase did not significantly modify the prevalence of 25(OH)D level≥30ng/mL in patients issued from the placebo group.

LIMITATIONS

Small size of the study population.

CONCLUSIONS

Oral weekly administration of 25,000IU of cholecalciferol for 13 weeks is an effective, safe, inexpensive, and manageable way to increase 25(OH)D and 1,25(OH)2D levels in hemodialysis patients. Further evaluation of clinical end points is suggested.

Accidental falls and risk of mortality among older adults on chronic peritoneal dialysis

BACKGROUND AND OBJECTIVES

More than 40% of elderly hemodialysis patients experience one or more accidental falls within a 1-year period. Such falls are associated with higher mortality. The objectives of this study were to assess whether falls are also common in elderly patients established on peritoneal dialysis and evaluate if patients with falls have a higher risk of mortality than patients who do not experience a fall.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a prospective cohort study design, patients ages ≥ 65 years on chronic peritoneal dialysis from April 2002 to April 2003 at the University Health Network were recruited. Patients were followed biweekly, and falls occurring within the first 15 months were recorded. Outcome data were collected until death, study end (July 31, 2012), transplantation, or transfer to another dialysis center.

RESULTS

Seventy-four of seventy-six potential patients were recruited, assessed at baseline, and followed biweekly for falls; 40 of 74 (54%) peritoneal dialysis patients experienced 89 falls (adjusted mean fall rate, 1.7 falls per patient-year; 95% confidence interval, 1.0 to 2.7). Patients with falls were more likely to have had previous falls, be more recently initiated onto dialysis, be men, be older, and have higher comorbidity. Twenty-eight patients died during the follow-up period. After adjustment for known risk factors, each successive fall was associated with a 1.62-fold higher mortality (hazard ratio, 1.62; 95% confidence interval, 1.29 to 2.02; P<0.001).

CONCLUSIONS

Accidental falls are common in the peritoneal dialysis population and often go unrecognized. Falls were associated with higher mortality risk. Because fall interventions are effective in other populations, screening peritoneal dialysis patients for falls may be a simple measure of clinical importance.

Falls among hemodialysis patients: potential opportunities for prevention?

Background

Falls among patients undergoing maintenance hemodialysis (HD) have significant consequences for quality of life and functional independence, morbidity, healthcare utilization and even mortality, but studies on the etiology of falls within large HD cohorts are limited.

Methods

Falls during the past 12 months were ascertained for a prevalent multi-center HD cohort (n = 762) aged 20–92 years, and associations with demographic and treatment characteristics, comorbidities, cognitive function, prescribed medications, balance tests, frailty and depressive symptoms were assessed.

Results

Falls were sustained by 28.4% of participants. In multivariable-adjusted analyses, participants classified as frail were over two times more likely to report falls [odds ratio (OR): 2.39, 95% confidence interval (CI): 1.22–4.71, P = 0.01], and participants with a CES-D score 18+ and/or prescribed antidepressants were over 80% more likely to be fallers (OR: 1.83, 95% CI: 1.23–2.74, P = 0.003) than were participants with a CES-D score <18 and no prescribed antidepressants.

Conclusions

Frailty and depressed mood, factors that are potentially modifiable, are prominently associated with falls.

Serum 25-hydroxy vitamin D concentrations are more deficient/insufficient in peritoneal dialysis than haemodialysis patients in a sunny climate

BACKGROUND

Research has identified associations between serum 25(OH)D and a range of clinical outcomes in chronic kidney disease and wider populations. The present study aimed to investigate vitamin D deficiency/insufficiency in dialysis patients and the relationship with vitamin D intake and sun exposure.

METHODS

A cross-sectional study was used. Participants included 30 peritoneal dialysis (PD) (43.3% male; 56.87 ± 16.16 years) and 26 haemodialysis (HD) (80.8% male; 63.58 ± 15.09 years) patients attending a department of renal medicine. Explanatory variables were usual vitamin D intake from diet/supplements (IU day(-1) ) and sun exposure (min day(-1) ). Vitamin D intake, sun exposure and ethnic background were assessed by questionnaire. Weight, malnutrition status and routine biochemistry were also assessed. Data were collected during usual department visits. The main outcome measure was serum 25(OH)D (nm).

RESULTS

Prevalence of inadequate/insufficient vitamin D intake differed between dialysis modality, with 31% and 43% found to be insufficient (<50 nm) and 4% and 33% found to be deficient (<25 nm) in HD and PD patients, respectively (P < 0.001). In HD patients, there was a correlation between diet and supplemental vitamin D intake and 25(OH)D (ρ = 0.84, P < 0.001) and average sun exposure and 25(OH)D (ρ = 0.50, P < 0.02). There were no associations in PD patients. The results remained significant for vitamin D intake after multiple regression, adjusting for age, gender and sun exposure.

CONCLUSIONS

The results highlight a strong association between vitamin D intake and 25(OH)D in HD but not PD patients, with implications for replacement recommendations. The findings indicate that, even in a sunny climate, many dialysis patients are vitamin D deficient, highlighting the need for exploration of determinants and consequences.

Oral postdialysis cholecalciferol supplementation in patients on maintenance hemodialysis: a dose-response approach

The aim of the present study was to evaluate the dose of postdialysis cholecalciferol needed to maintain the 25-hydroxyvitamin D [25(OH)D] levels in the optimal range of 75–150 nmol/L. Twenty-six patients who had low baseline 25(OH)D levels (mean 27.5 ± 14.9 nmol/L) were studied. The 25(OH)D levels were measured every 2 months for one year. During the first two months, all the patients received 2000 IU of cholecalciferol after each hemodialysis (=6000 IU/wk). Thereafter, the dose was individualized and adapted every 2 months by administering 1 to 6 cholecalciferol tablets (2000 IU each) per week (total weekly dose = 2000–12000 IU/wk). During cholecalciferol supplementation, the 25(OH)D concentrations rapidly increased from baseline to 140.1 ± 28.3 nmol/L at month 6 and 95.6 ± 20.9 nmol/L at month 12. At month twelve, 86% of the patients had 25(OH)D levels within the target range with a mean dose of 5917 ± 4106 IU/wk of cholecalciferol; however, the amount needed to maintain these levels varied widely from 0 (n = 2) to 12000 IU/wk (n = 5). In conclusion, postdialysis cholecalciferol prescription is quite effective in correcting vitamin D deficiency/insufficiency, but the amount of cholecalciferol needed to maintain the 25(OH)D levels within the optimal range over the long-term varies widely among patients and must be individualized.

Uremic osteoporosis

Abnormalities in bone turnover, mineralization, and volume represent one of the three components of chronic kidney disease–related mineral and bone disorder (CKD-MBD). The risk of hip fracture is considerably high, while the risk of spinal compression fracture may not be more elevated among CKD patients than in general population. The relationship between bone fracture and bone mineral density in CKD patients is more complex than in those without kidney disease. An increase in the rate of falls has been reported to be a major cause of high hip fracture risk among CKD patients; however, it certainly is not the only underlying mechanism. Abnormal parathyroid function is not likely to be a major cause of hip fracture among CKD patients. In experimental CKD animals, mechanical elasticity properties of long bones showed an inverse correlation with kidney function. The deterioration of bone elasticity showed a significant correlation with bone biochemical changes. Of note, administration of the oral absorbent AST-120 was capable of preventing both changes. These findings suggest that uremic toxins cause a deterioration of bone material properties, and changes in material properties disturb bone elasticity. This disease concept cannot be considered to be a direct consequence of CKD-MBD. We therefore would like to call it ‘uremic osteoporosis'. This entity may be a major cause of increased hip fracture risk among CKD patients.

Calculated free and bioavailable vitamin D metabolite concentrations in vitamin D-deficient hip fracture patients after supplementation with cholecalciferol and ergocalciferol

We previously showed that oral cholecalciferol and ergocalciferol have comparable effects in decreasing circulating parathyroid hormone (PTH), despite a greater increase in total serum 25-hydroxyvitamin D (25OHD) concentration with cholecalciferol supplementation. However, the effects of cholecalciferol and ergocalciferol on total serum 1,25-dihydroxyvitamin D (1,25(OH)2D), vitamin D-binding protein (DBP), free 25OHD and free 1,25(OH)2D concentrations have not been previously studied. We randomized 95 hip fracture patients (aged 83±8 years) with vitamin D deficiency (serum 25OHD <50 nmol/L) to oral supplementation with either cholecalciferol 1000 IU/day (n=47) or ergocalciferol 1000 IU/day (n=48) for three months. All were given matching placebos of the alternative treatment to maintain blinding. We measured serum 25OHD (high-pressure liquid chromatography), 1,25(OH)2D (Diasorin radioimmunoassay), DBP (immunonephelometry), ionized calcium (Bayer 800 ion-selective electrode) and albumin (bromocresol green) concentrations before and after treatment. We calculated free and bioavailable concentrations of the vitamin D metabolites using albumin and DBP, and calculated free vitamin D metabolite indices as the ratios between the molar concentrations of the vitamin D metabolites and DBP. Seventy participants (74%) completed the study with paired samples for analysis. Total serum 1,25(OH)2D did not change significantly with either treatment (p>0.05, post-treatment vs baseline). Both treatments were associated with comparable increases in DBP (cholecalciferol: +18%, ergocalciferol: +16%, p=0.32 between groups), albumin (cholecalciferol: +31%, ergocalciferol: +21%, p=0.29 between groups) and calculated free 25OHD (cholecalciferol: +46%, ergocalciferol: +36%, p=0.08), with comparable decreases in free 1,25(OH)2D (cholecalciferol: -17%, ergocalciferol: -19%, p=0.32 between groups). In the treatment-adherent subgroup the increase in ionized calcium was marginally greater with cholecalciferol compared with ergocalciferol (cholecalciferol: +8%, ergocalciferol: +5%, p=0.03 between groups). There were no significant differences between the treatments in their effects on the calculated bioavailable concentrations or free indices of the vitamin D metabolites (p>0.05 between groups). In vitamin D-deficient hip fracture patients, oral supplementation with cholecalciferol and ergocalciferol had no effect on total serum 1,25(OH)2D, and comparable effects on DBP and free vitamin D metabolite concentrations. This is despite cholecalciferol having greater effects than ergocalciferol in increasing total 25OHD, and in increasing ionized calcium in treatment-adherent subjects. These findings may explain why cholecalciferol and ergocalciferol supplementation result in similar magnitudes of PTH reduction, but implicate potential differences in other vitamin D metabolites, such as 24,25(OH)2D, that could explain their different effects on ionized calcium.

Avaliação da capacidade da Escala Internacional de Eficácia de Quedas em discriminar risco de quedas em pacientes com doença renal crônica submetidos à hemodiálise

O objetivo deste estudo foi avaliar a capacidade da Escala Internacional de Eficácia de quedas (FES-I), dos níveis séricos de paratormônio (PTH) e do tempo de tratamento hemodialítico (TTH) de discriminar pacientes com doença renal crônica (DRC) em tratamento hemodialítico caidores de não caidores. Foi realizado estudo transversal com 64 pacientes, com idade média de 44,2±14,8 anos. Foram coletados dados antropométricos, níveis séricos de PTH, histórico e risco de quedas (Escala Internacional de Eficácia de Quedas - FES-I), TTH e o nível de atividade física (Questionário Internacional de Atividade Física - IPAQ). Foram encontrados níveis séricos de PTH elevados em 64,1% dos pacientes, e 17,2% deles relataram histórico de queda no último ano. O tempo médio de TTH foi 50,3±37,5 meses. Nível de atividade física leve foi encontrado em 64,1%. Foi encontrada correlação positiva entre o PTH e o TTH (r=0,47; p<0,001). Não foram encontradas correlação entre o FES-I e o PTH (p<0,131), entre o FES-I e o TTH (p<0,153) nem entre o PTH (valor baixo/normal <450 pg/mL e valor elevado >450 pg/mL) e o risco de queda (caidores e não caidores) (p<0,158). No estudo, o instrumento FES-I mostrou-se capaz de discriminar hemodialíticos caidores de não caidores. Concluímos que a FES-I apresentou bom desempenho de avaliação entre caidores e não caidores, no entanto não foi observada associação entre caidores com os níveis séricos do PTH e com o TTH.

Effects of cholecalciferol on functional, biochemical, vascular, and quality of life outcomes in hemodialysis patients

BACKGROUND AND OBJECTIVES

Observational studies suggest that calciferol supplementation may improve laboratory and patient-level outcomes of hemodialysis patients with reduced 25-hydroxyvitamin D [25(OH)D] levels. This randomized controlled trial examined effects of cholecalciferol supplementation in patients on hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Sixty patients with 25(OH)D levels ≤24 ng/ml (≤60 nmol/L) were randomized to receive 50,000 IU oral cholecalciferol or placebo, once weekly for 8 weeks and then monthly for 4 months. At baseline (autumn 2011) and 6 months, testing evaluated muscle strength, functional capacity, laboratory parameters, pulse wave velocity (PWV), and health-related quality of life (HRQOL) using the Kidney Disease Quality of Life-36 survey.

RESULTS

Patients were well matched by treatment allocation. Median age was 62 years (range, 20-86), 52% were women, 55% had a history of diabetes, and mean serum 25(OH)D was 17±5 ng/ml (43±13 nmol/L). Patients were assessed over 6 months by repeated-measures ANOVA. Patients allocated to cholecalciferol had significantly higher values of 25(OH)D (P<0.001), 1,25-dihydroxyvitamin D (P=0.04), and tartrate-resistant acid phosphatase-5b) (P=0.04) and a greater reduction in phosphorus values (P=0.03) than placebo-treated patients Values of serum calcium, intact parathyroid hormone, and episodes of hypercalcemia and hyperphosphatemia did not differ significantly between the groups. No significant differences were detected in muscle strength, functional capacity, PWV, or HRQOL.

CONCLUSIONS

In this randomized controlled trial, patients supplemented with cholecalciferol had higher 25(OH)D, 1,25-dihydroxyvitamin D, and tartrate-resistant acid phosphatase-5b levels, without increased calcium or phosphorus values. However, no effects were detected in muscle strength, functional capacity, PWV, or HRQOL.