Vitamin D and Secondary Hyperparathyroidism in Chronic Kidney Disease: A Critical Appraisal of the Past, Present, and the Future

Identification of crucial genes and possible molecular pathways associated with active vitamin D intervention in diabetic kidney disease

Background

A significant cause of advanced renal failure is diabetic nephropathy (DKD), with few treatment options available. Calcitriol shows potential in addressing fibrosis related to DKD, though its molecular mechanisms remain poorly understood. This research seeks to pinpoint the crucial genes and pathways influenced by calcitriol within the scope of DKD-related fibrosis.

Methods

Single-cell gene expression profiling of calcitriol treated DKD rat kidney tissue and screening of fibrosis-associated cell subsets. Mendelian randomization and enrichment analyses (CIBERSORT, GSVA, GSEA, Motif Enrichment) were used to explore gene-immune cell interactions and signaling pathways. Key findings were validated using independent datasets and protein expression data from the Human Protein Atlas.

Results

Calcitriol treatment reduced proliferative cell populations and highlighted the FoxO signaling pathway's role in DKD. SUMO3 and CD74 were identified as key markers linked to immune infiltration and renal function. These genes were significantly associated with creatinine levels and eGFR, indicating their potential role in DKD progression.

Conclusion

Our results suggest that calcitriol modulates DKD fibrosis through the FoxO pathway, with SUMO3 and CD74 serving as potential biomarkers for kidney protection. These results provide fresh insights into strategies for treating DKD.

Current therapeutic approach of chronic kidney disease-mineral and bone disorder

Chronic kidney disease (CKD) has emerged as one of the leading noncommunicable diseases affecting >10% of the population worldwide. Bone and mineral disorders are a common complication among patients with CKD resulting in a poor life quality, high fracture risk, increased morbidity and cardiovascular mortality. According to Kidney Disease: Improving Global Outcomes, renal osteodystrophy refers to changes in bone morphology found in bone biopsy, whereas CKD-mineral and bone disorder (CKD-MBD) defines a complex of disturbances including biochemical and hormonal alterations, disorders of bone and mineral metabolism and extraskeletal calcification. As a result, the management of CKD-MBD should focus on the aforementioned parameters, including the treatment of hyperphosphatemia, hypocalcemia, abnormal PTH and vitamin D levels. Regarding the bone fragility fractures, osteoporosis and renal osteodystrophy, which constitute the bone component of CKD-MBD, anti-osteoporotic agents constitute the mainstay of treatment. However, a thorough elucidation of the CKD-MBD pathogenesis is crucial for the ideal personalized treatment approach. In this paper, we review the pathology and management of CKD-MBD based on the current literature with special attention to recent advances.

Secondary hyperparathyroidism in chronic kidney disease: A narrative review focus on therapeutic strategy

Chronic kidney disease (CKD) affects over 10% of the global population. One crucial complication of CKD is secondary hyperparathyroidism (SHPT), marked by elevated parathyroid hormone levels due to hyperphosphataemia, hypocalcaemia, and low active vitamin D from impaired renal function. SHPT increases risks of bone deformities, vascular calcification, cardiovascular events and mortality. This review examines SHPT treatment strategies in patients with CKD. First-line treatments include phosphate binders, vitamin D receptor activators and calcimimetics. When these fail, invasive options like parathyroidectomy (PTX) and thermal ablation are considered. PTX effectively reduces symptoms and improves radiological outcomes, outperforming medical treatment alone in reducing cardiovascular risk and mortality. Thermal ablation techniques, such as microwave, radiofrequency, laser or high-intensity focused ultrasound, offer less invasive alternatives with promising results. Future research should explore the molecular mechanisms of parathyroid gland hyperplasia and evaluate various treatments' impacts.

Sustained Reduction of Elevated Intact Parathyroid Hormone Concentrations with Extended-Release Calcifediol Slows Chronic Kidney Disease Progression in Secondary Hyperparathyroidism Patients

INTRODUCTION

Chronic kidney disease (CKD) drives onerous human and healthcare costs, underscoring an urgent need to avert disease progression. Secondary hyperparathyroidism (SHPT) develops as CKD advances, and persistently elevated parathyroid hormone (PTH) may be nephrotoxic and associated with earlier dialysis onset. This study examines, for the first time, the hypothesis that sustained reduction of elevated intact PTH (iPTH) with extended-release calcifediol (ERC) reduces the nephrotoxic impact of SHPT and forestalls renal decline.

METHODS

Changes in estimated glomerular filtration rate (eGFR) were analyzed post hoc in 126 adults with SHPT, stage 3-4 CKD, and low serum 25-hydroxyvitamin D (25D) treated for 1 year with ERC in pivotal trials. ERC was administered at 30 μg/day increasing, as needed, to 60 μg/day to achieve ≥30% reductions in iPTH. Calcium, phosphorus, 25D, 1,25-dihydroxyvitamin D (1,25D), iPTH, eGFR, fibroblast growth factor-23 (FGF23), bone turnover markers (BTMs), and urine albumin-to-creatinine ratio (uACR) were measured at baseline and regular intervals. Participants were categorized by achievement (or not) of sustained ≥30% iPTH reductions over the last 2 quarters of treatment to evaluate differences in eGFR decline.

RESULTS

For all participants, 25D increased 58.5 ± 2.3 (SE) ng/mL (p < 0.001) by the end of treatment (EOT), 1,25D increased 10.1 ± 1.8 pg/mL (p < 0.001), iPTH decreased from 143.8 ± 5.8 pg/mL to 108.8 ± 7.2 (p < 0.001), BTMs improved (p < 0.01), and eGFR declined 2.2 ± 0.5 mL/min/1.73 m2 (p < 0.001). The rate of eGFR decline was >5-fold higher (p = 0.014) in participants who did not achieve sustained iPTH reductions of ≥30% (3.2 ± 0.7; 12.7 ± 2.2%) than in those who did (0.6 ± 0.8; 2.9 ± 2.4%). It was highest in the 30 participants who did not exhibit an iPTH lowering response in both of the last 2 quarters of treatment (5.4 ± 0.9; 20.9 ± 3.4%). Duration of iPTH reduction had no impact on safety parameters. Degree of iPTH reduction at EOT was also associated with slower CKD progression.

CONCLUSION

Sustained reduction of elevated iPTH with ERC treatment was associated with slower rates of eGFR decline in patients with SHPT and stage 3-4 CKD without raising safety concerns. A prospective trial is warranted to confirm this finding.

Chest X-ray Findings and Prognostic Factors in Survival Analysis in Peritoneal Dialysis and Hemodialysis Patients: A Retrospective Cross-Sectional Study

Background and Objectives: This study aims to analyze survival in peritoneal and hemodialysis patients using chest radiography and biochemical parameters, determine common dialysis etiologies and causes of death, reveal prognostic factors, and contribute to clinical practice. Materials and Methods: A retrospective cross-sectional study was conducted with data from 33 peritoneal dialysis and 37 hemodialysis patients collected between October 2018 and February 2020. Survival and mortality were retrospectively tracked over 70 months (October 2018-June 2024). Chest X-ray measurements (cardiothoracic index, pulmonary vascular pedicle width, right pulmonary artery diameter, diaphragmatic height) and biochemical parameters (urea, albumin, creatinine, parathormone, ferritin, hemoglobin, arterial blood gas, potassium) were analyzed for their impact on survival. Statistical analyses included descriptive statistics, chi-square test, Fisher's exact test, Bayesian analysis, McNemar test, Kaplan-Meier survival analysis, Cox regression, Bayesian correlation test, linear regression analysis (scatter plot), and ROC analysis. SPSS 20.0 was used for data analysis, with p < 0.05 considered statistically significant. Results: Hypertension, type 2 diabetes, and urogenital disorders were the main dialysis etiologies. Peritonitis (38.5%) and cardiovascular diseases (47.4%) were the leading causes of death in peritoneal and hemodialysis patients, respectively. Significant chest X-ray differences included pulmonary vascular pedicle width and pulmonary artery diameter in hemodialysis and diaphragm height in peritoneal dialysis. Kaplan-Meier showed no survival difference between methods. Cox regression identified age, intact parathormone levels, iPTH/PVPW ratio, and clinical status as survival and mortality factors. The iPTH/PVPW ratio cut-off for mortality prediction was ≤6.8. Conclusions: Age, intact parathormone levels, pulmonary vascular pedicle width, and clinical status significantly impact survival in dialysis patients. Management of hypertension and diabetes, management and follow-up of urogenital disorders, infection control, patient education, and regular cardiovascular check-ups may improve survival rates. Additionally, the iPTH/PVPW ratio can predict mortality risk.

Association between dietary intake of selenium and chronic kidney disease in US adults: a cross-sectional study of NHANES 2015-2018

Background

Chronic kidney disease (CKD) is currently a widespread chronic illness, and its development is influenced by nutrients. Selenium plays a crucial role in the intervention and therapy of various chronic illness. In this study, we aimed to investigate the connection between dietary selenium intake and CKD in adults in the United States.

Methods

We included 6,390 individuals from the datasets of the National Health and Nutrition Examination Survey (NHANES) between 2015 and 2018. We used multiple logistic regression, restricted cubic spline regression, and forest plots to investigate the connection between dietary selenium intake and CKD.

Results

After fully adjusting the data of 6,390 individuals from NHANES between 2015 and 2018, 1,523 (23.83%) of the individuals were identified as having chronic kidney disease (CKD). The rates of CKD in participants with average selenium intakes of ≤0.072, 0.072-0.103, 0.103-0.144, and > 0.144 mg/day were 27.53, 25.11, 22.42, and 19.96%, respectively. After adjusting for potential confounding factors, the fully adjusted odds ratio (OR) values for CKD according to dietary selenium intake were 1 (reference), 0.94 (95% confidence interval (CI): 0.79-1.12, p = 0.466), 0.82 (95% CI:0.68-0.98, p = 0.033), and 0.77 (95% CI:0.63-0.95, p = 0.016) for the four selenium intake levels, respectively, with P trend = 0.007. The dietary selenium intake was negatively associated with the incidence of CKD, after adjusting for other confounding factors. The risk of CKD decreased by 7.7% for every additional 0.1 mg of dietary selenium intake.

Conclusion

A higher dietary selenium intake correlates significantly and negatively with the incidence of CKD.

High prevalence of vitamin D deficiency in Taiwanese patients with inflammatory bowel disease

Vitamin D deficiency is common in patients with inflammatory bowel disease (IBD). In this study, we aimed to evaluate the prevalence and risk factors of vitamin D deficiency in a Taiwanese IBD cohort. Vitamin D levels were checked in adult patients with IBD who were treated at Changhua Christian Hospital, a medical center in central Taiwan, from January 2017 to December 2023. The risk factors for vitamin D deficiency were evaluated. 106 adult IBD patients were included, including 20 patients with Crohn's disease and 86 with ulcerative colitis. The median age at diagnosis was 39.2 years. The mean vitamin D level was 22.2 ± 8 ng/mL. Forty-five patients (42.5%) had vitamin D deficiency (vitamin D level < 20 ng/mL). Comparing patients with normal vitamin D levels and those with vitamin D deficiency after multivariate adjustment, female sex and early age at diagnosis were identified as statistically significant risk factors. We found a prevalence of 42.5% of vitamin D deficiency in the Taiwanese IBD population. Understanding this issue is essential for teaching patients and doctors about vitamin D deficiency screening and improving patient outcomes.

Vitamin D: A Bridge between Kidney and Heart

Chronic kidney disease (CKD) and cardiovascular disease (CVD) are highly prevalent conditions, each significantly contributing to the global burden of morbidity and mortality. CVD and CKD share a great number of common risk factors, such as hypertension, diabetes, obesity, and smoking, among others. Their relationship extends beyond these factors, encompassing intricate interplay between the two systems. Within this complex network of pathophysiological processes, vitamin D has emerged as a potential linchpin, exerting influence over diverse physiological pathways implicated in both CKD and CVD. In recent years, scientific exploration has unveiled a close connection between these two prevalent conditions and vitamin D, a crucial hormone traditionally recognized for its role in bone health. This article aims to provide an extensive review of vitamin D's multifaceted and expanding actions concerning its involvement in CKD and CVD.

Chronic Kidney Disease Diets for Kidney Failure Prevention: Insights from the IL-11 Paradigm

Nearly every fifth adult in the United States and many older adults worldwide are affected by chronic kidney disease (CKD), which can progress to kidney failure requiring invasive kidney replacement therapy. In this review, we briefly examine the pathophysiology of CKD and discuss emerging mechanisms involving the physiological resolution of kidney injury by transforming growth factor beta 1 (TGFβ1) and interleukin-11 (IL-11), as well as the pathological consequences of IL-11 overproduction, which misguides repair processes, ultimately culminating in CKD. Taking these mechanisms into account, we offer an overview of the efficacy of plant-dominant dietary patterns in preventing and managing CKD, while also addressing their limitations in terms of restoring kidney function or preventing kidney failure. In conclusion, this paper outlines novel regeneration strategies aimed at developing a reno-regenerative diet to inhibit IL-11 and promote repair mechanisms in kidneys affected by CKD.

Metabolic disorders in prediabetes: From mechanisms to therapeutic management

Diabetes, one of the world's top ten diseases, is known for its high mortality and complication rates and low cure rate. Prediabetes precedes the onset of diabetes, during which effective treatment can reduce diabetes risk. Prediabetes risk factors include high-calorie and high-fat diets, sedentary lifestyles, and stress. Consequences may include considerable damage to vital organs, including the retina, liver, and kidneys. Interventions for treating prediabetes include a healthy lifestyle diet and pharmacological treatments. However, while these options are effective in the short term, they may fail due to the difficulty of long-term implementation. Medications may also be used to treat prediabetes. This review examines prediabetic treatments, particularly metformin, glucagon-like peptide-1 receptor agonists, sodium glucose cotransporter 2 inhibitors, vitamin D, and herbal medicines. Given the remarkable impact of prediabetes on the progression of diabetes mellitus, it is crucial to intervene promptly and effectively to regulate prediabetes. However, the current body of research on prediabetes is limited, and there is considerable confusion surrounding clinically relevant medications. This paper aims to provide a comprehensive summary of the pathogenesis of pre-diabetes mellitus and its associated therapeutic drugs. The ultimate goal is to facilitate the clinical utilization of medications and achieve efficient and timely control of diabetes mellitus.

Hyperparathyroidism, Serum Phosphorus and Dietary Intake in Hemodialysis Patients: Is There a Novel Relationship?

The management of hyperparathyroidism (intact parathyroid hormone (iPTH) serum levels > 585 pg/mL), frequently focuses on the appropriate control of mineral and bone markers, with the decrease in serum and dietary phosphorus as two of the targets. We aimed to investigate the association between iPTH, serum phosphorus levels and dietary intake. This was a cross-sectional, multicenter, observational study with 561 patients on hemodialysis treatment. Clinical parameters, body composition and dietary intake were assessed. For the analysis, patients were divided into three groups: (a) iPTH < 130, (b) iPTH between 130 and 585 and (c) iPTH > 585 pg/mL. The association between PTH, serum phosphorus and dietary intake was analyzed using linear regression models. In the whole sample, 23.2% of patients presented an iPTH > 585 pg/mL. Patients with higher iPTH levels were those with longer HD vintage and lower ages, higher serum phosphorus, serum calcium, Ca/P product, albumin and caffeine intake, and a lower dietary intake of phosphorus, fiber, riboflavin and folate. Higher serum phosphorus predicted higher iPTH levels, even in the adjusted model. However, lower dietary phosphorus and fiber intake were predictors of higher iPTH levels, including in the adjusted model. Our results bring new data to the relationship between dietary intake and iPTH values. Despite higher serum phosphorus being observed in patients with HPTH, an opposite association was noted regarding dietary phosphate and fiber.

The Efficacy and Safety of High-Dose Cholecalciferol Therapy in Hemodialysis Patients

Vitamin D deficiency and insufficiency are highly prevalent in CKD, affecting over 80% of hemodialysis (HD) patients and requiring therapeutic intervention. Nephrological societies suggest the administration of cholecalciferol according to the guidelines for the general population. The aim of the observational study was to evaluate the efficacy and safety of the therapy with a high dose of cholecalciferol in HD patients with 25(OH)D deficiency and insufficiency to reach the target serum 25(OH)D level > 30 ng/mL. A total of 22 patients (16 M), with an average age of 72.5 ± 13.03 years and 25(OH)D concentration of 13.05 (9.00-17.90) ng/mL, were administered cholecalciferol at a therapeutic dose of 70,000 IU/week (20,000 IU + 20,000 IU + 30,000 IU, immediately after each dialysis session). All patients achieved the target value > 30 ng/mL, with a mean time of 2.86 ± 1.87 weeks. In the first week, the target level of 25(OH)D (100%) was reached by 2 patients (9.09%), in the second week by 15 patients (68.18%), in the fourth week by 18 patients (81.18%), and in the ninth week by all 22 patients (100%). A significant increase in 1,25(OH)2D levels was observed during the study. However, only 2 patients (9.09%) achieved a concentration of 1,25(OH)2D above 25 ng/mL-the lower limit of the reference range. The intact PTH concentrations remained unchanged during the observation period. No episodes of hypercalcemia were detected, and one new episode of hyperphosphatemia was observed. In conclusion, our study showed that the administration of a high-therapeutic dose of cholecalciferol allowed for a quick, effective, and safe leveling of 25(OH)D concentration in HD patients.

Secondary Hyperparathyroidism

Secondary hyperparathyroidism (SHPT) does not initiate as a primary dysfunction of parathyroid glands resulting from an intrinsic defect or disease but is the physiologic response of parathyroids to metabolic changes elsewhere in the body occurring over time. SHPT is a manifestation of a chronic condition that classically occurs from chronic kidney disease. In fact, given the relatively recent transition of populations from outside (agrarian) to indoor (industrial, information technology, and so forth) employment and a consequent reduction in sun exposure, combined with diets of highly processed food, vitamin D and calcium deficiencies are now the leading causes of SHPT.

SARS-CoV-2 and its Multifaceted Impact on Bone Health: Mechanisms and Clinical Evidence

PURPOSE OF REVIEW

SARS-CoV-2 infection, the culprit of the COVID-19 pandemic, has been associated with significant long-term effects on various organ systems, including bone health. This review explores the current understanding of the impacts of SARS-CoV-2 infection on bone health and its potential long-term consequences.

RECENT FINDINGS

As part of the post-acute sequelae of SARS-CoV-2 infection, bone health changes are affected by COVID-19 both directly and indirectly, with multiple potential mechanisms and risk factors involved. In vitro and preclinical studies suggest that SARS-CoV-2 may directly infect bone marrow cells, leading to alterations in bone structure and osteoclast numbers. The virus can also trigger a robust inflammatory response, often referred to as a "cytokine storm", which can stimulate osteoclast activity and contribute to bone loss. Clinical evidence suggests that SARS-CoV-2 may lead to hypocalcemia, altered bone turnover markers, and a high prevalence of vertebral fractures. Furthermore, disease severity has been correlated with a decrease in bone mineral density. Indirect effects of SARS-CoV-2 on bone health, mediated through muscle weakness, mechanical unloading, nutritional deficiencies, and corticosteroid use, also contribute to the long-term consequences. The interplay of concurrent conditions such as diabetes, obesity, and kidney dysfunction with SARS-CoV-2 infection further complicates the disease's impact on bone health. SARS-CoV-2 infection directly and indirectly affects bone health, leading to potential long-term consequences. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

COVID-19 and Bone Loss: A Review of Risk Factors, Mechanisms, and Future Directions

PURPOSE OF REVIEW

SARS-CoV-2 drove the catastrophic global phenomenon of the COVID-19 pandemic resulting in a multitude of systemic health issues, including bone loss. The purpose of this review is to summarize recent findings related to bone loss and potential mechanisms.

RECENT FINDINGS

The early clinical evidence indicates an increase in vertebral fractures, hypocalcemia, vitamin D deficiencies, and a loss in BMD among COVID-19 patients. Additionally, lower BMD is associated with more severe SARS-CoV-2 infection. Preclinical models have shown bone loss and increased osteoclastogenesis. The bone loss associated with SARS-CoV-2 infection could be the result of many factors that directly affect the bone such as higher inflammation, activation of the NLRP3 inflammasome, recruitment of Th17 cells, the hypoxic environment, and changes in RANKL/OPG signaling. Additionally, SARS-CoV-2 infection can exert indirect effects on the skeleton, as mechanical unloading may occur with severe disease (e.g., bed rest) or with BMI loss and muscle wasting that has also been shown to occur with SARS-CoV-2 infection. Muscle wasting can also cause systemic issues that may influence the bone. Medications used to treat SARS-CoV-2 infection also have a negative effect on the bone. Lastly, SARS-CoV-2 infection may also worsen conditions such as diabetes and negatively affect kidney function, all of which could contribute to bone loss and increased fracture risk. SARS-CoV-2 can negatively affect the bone through multiple direct and indirect mechanisms. Future work will be needed to determine what patient populations are at risk of COVID-19-related increases in fracture risk, the mechanisms behind bone loss, and therapeutic options. This review article is part of a series of multiple manuscripts designed to determine the utility of using artificial intelligence for writing scientific reviews.

The impact of diabetes, anemia, and renal function in the relationship between osteoporosis and fasting blood glucose among Taiwanese women: a cross-sectional study

BACKGROUND

The aim of this study was to investigate the association between fasting blood glucose and osteoporosis in women with diabetes, anemia, and renal function.

METHODS

The medical records of women who underwent a general health examination at a regional hospital in southern Taiwan were retrospectively reviewed. Logistic regression analysis was performed to assess the association between osteoporosis and fasting blood glucose separately for the eight subgroups (diabetes or non-diabetes, anemia or non-anemia, normal or decreased renal function), adjusting for other clinical characteristics and laboratory findings.

RESULTS

A total of 11,872 women were included in the study. Among women with diabetes, anemia, and decreased renal function, an increment of 10 mg/dL in fasting blood glucose was associated with an increased risk of osteoporosis (adjusted odds ratio [aOR] = 1.57, p = 0.004). Among women without diabetes, fasting blood glucose was significantly associated with an increased risk of osteoporosis in those with anemia and normal renal function (OR = 1.14, p = 0.023) and those without anemia and normal renal function (OR = 1.04, p = 0.015), but these associations were not significant after adjusting for other covariates.

CONCLUSIONS

Higher fasting blood glucose levels in women with diabetes, anemia, and decreased renal function were associated with an increased risk of osteoporosis. Clinicians should be vigilant about glucose control in patients with diabetes to reduce the risk of fracture.

Mixed uremic osteodystrophy: an ill-described common bone pathology in patients with chronic kidney disease

Renal osteodystrophy (ROD) starts early and progresses with further loss of kidney function in patients with chronic kidney disease (CKD). There are four distinct types of ROD based on undecalcified bone biopsy results. Adynamic bone disease and osteomalacia are the predominant forms of low bone turnover, while hyperparathyroid bone disease and mixed uremic osteodystrophy (MUO) are typically associated with high bone turnover. MUO is a prevalent but poorly described pathology that demonstrates evidence of osteomalacia on top of the high bone formation/resorption. The prevalence of MUO ranges from 5 to 63% among different studies. The pathogenesis of MUO is multi-factorial. Altered phosphate homeostasis, hypocalcemia, vitamin D deficiency, increased FGF-23, interleukins 1 and 6, TNF-α, amyloid, and heavy metal accumulation are the main inducers of MUO. The clinical findings of MUO are usually non-specific. The use of non-invasive testing such as bone turnover markers and imaging techniques might help to suspect MUO. However, it is usually impossible to precisely diagnose this condition without performing bone biopsy. The principal management of MUO is to control the maladaptive hyperparathyroidism along with correcting any nutritional mineral deficiencies that may induce mineralization defect. MUO is a common but still poorly understood bone pathology category; it demonstrates the complexity and difficulty in understanding ROD. A large prospective bone biopsy-based studies are needed for better identification as proper diagnosis and management would improve the outcome of patients with MUO.

Mini review: A reevaluation of nutritional vitamin D in the treatment of chronic kidney disease

Chronic kidney disease-mineral and bone disorder is a syndrome of mineral and bone metabolism abnormalities caused by chronic kidney disease. Osteoporosis is a systemic metabolic bone disease characterized by low bone mass, disruption of bone microstructure, increased brittleness, and a higher propensity for fractures. Both of these conditions significantly affect bone metabolism and substantially increase the risk of fractures. Nutritional vitamin D is an essential trace element in the human body and an important fat-soluble vitamin. One crucial physiological role of nutritional vitamin D is to achieve mineral-bone metabolism balance by regulating calcium homeostasis. This review summarized the metabolism of vitamin in normal population and its specificity in chronic kidney disease. Over the years, the understanding and application of vitamin D in patients with chronic renal failure is changing. As people pay more attention to hypercalcemia, vascular calcification, osteoporosis, nutritional vitamin D has come into people's attention again. More and more studies are discussing how to prescribe vitamin D supplementation in hemodialysis patients.

Pharmacological Nephroprotection in Non-Diabetic Chronic Kidney Disease-Clinical Practice Position Statement of the Polish Society of Nephrology

Chronic kidney disease (CKD) is a modern epidemic worldwide. Introducing renin-angiotensin system (RAS) inhibitors (i.e., ACEi or ARB) not only as blood-pressure-lowering agents, but also as nephroprotective drugs with antiproteinuric potential was a milestone in the therapy of CKD. For decades, this treatment remained the only proven strategy to slow down CKD progression. This situation changed some years ago primarily due to the introduction of drugs designed to treat diabetes that turned into nephroprotective strategies not only in diabetic kidney disease, but also in CKD unrelated to diabetes. In addition, several drugs emerged that precisely target the pathogenetic mechanisms of particular kidney diseases. Finally, the role of metabolic acidosis in CKD progression (and not only the sequelae of CKD) came to light. In this review, we aim to comprehensively discuss all relevant therapies that slow down the progression of non-diabetic kidney disease, including the lowering of blood pressure, through the nephroprotective effects of ACEi/ARB and spironolactone independent from BP lowering, as well as the role of sodium-glucose co-transporter type 2 inhibitors, acidosis correction and disease-specific treatment strategies. We also briefly address the therapies that attempt to slow down the progression of CKD, which did not confirm this effect. We are convinced that our in-depth review with practical statements on multiple aspects of treatment offered to non-diabetic CKD fills the existing gap in the available literature. We believe that it may help clinicians who take care of CKD patients in their practice. Finally, we propose the strategy that should be implemented in most non-diabetic CKD patients to prevent disease progression.

Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines

Chronic kidney disease (CKD) is a highly prevalent condition worldwide in which the kidneys lose many abilities, such as the regulation of vitamin D (VD) metabolism. Moreover, people with CKD are at a higher risk of multifactorial VD deficiency, which has been extensively associated with poor outcomes, including bone disease, cardiovascular disease, and higher mortality. Evidence is abundant in terms of the association of negative outcomes with low levels of VD, but recent studies have lowered previous high expectations regarding the beneficial effects of VD supplementation in the general population. Although controversies still exist, the diagnosis and treatment of VD have not been excluded from nephrology guidelines, and much data still supports VD supplementation in CKD patients. In this narrative review, we briefly summarize evolving controversies and useful clinical approaches, underscoring that the adverse effects of VD derivatives must be balanced against the need for effective prevention of progressive and severe secondary hyperparathyroidism. Guidelines vary, but there seems to be general agreement that VD deficiency should be avoided in CKD patients, and it is likely that one should not wait until severe SHPT is present before cautiously starting VD derivatives. Furthermore, it is emphasized that the goal should not be the complete normalization of parathyroid hormone (PTH) levels. New developments may help us to better define optimal VD and PTH at different CKD stages, but large trials are still needed to confirm that VD and precise control of these and other CKD-MBD biomarkers are unequivocally related to improved hard outcomes in this population.

Chronic Kidney Disease-State of Either "Too Much" or "Too Little"

Chronic kidney disease (CKD) is a world-wide phenomenon with an increasing incidence and prevalence [...].

Definition, Assessment, and Management of Vitamin D Inadequacy: Suggestions, Recommendations, and Warnings from the Italian Society for Osteoporosis, Mineral Metabolism and Bone Diseases (SIOMMMS)

In the recent years, both the prescriptions of serum 25(OH)D levels assay, and vitamin D supplementation are constantly increasing, as well as the costs to be incurred relating to these specific aspects. As in many other countries, the risk of vitamin D deficiency is particularly high in Italy, as recently confirmed by cohort studies in the general population as well as in patients with metabolic bone disorder. Results confirmed the North-South gradient of vitamin D levels described among European countries, despite the wide use of supplements. Although vitamin D supplementation is also recommended by the Italian Medicine Agency for patients at risk for fragility fracture or for initiating osteoporotic medication, the therapeutic gap for osteoporosis in Italy is very high. There is a consistent proportion of osteoporotic patients not receiving specific therapy for osteoporosis following a fragility fracture, with a poor adherence to the recommendations provided by national guidelines and position paper documents. The failure or inadequate supplementation with vitamin D in patients on antiresorptive or anabolic treatment for osteoporosis is thought to further amplify the problem and exposes patients to a high risk of re-fracture and mortality. Therefore, it is important that attention to its possible clinical consequences must be given. Thus, in light of new evidence from the literature, the SIOMMMS board felt the need to revise and update, by a GRADE/PICO system approach, its previous original recommendations about the definition, prevention, and treatment of vitamin D deficiency in adults, released in 2011. Several key points have been here addressed, such as the definition of the vitamin D status: normality values and optimal values; who are the subjects considered at risk of hypovitaminosis D; opportunity or not of performing the biochemical assessment of serum 25(OH)D levels in general population and in subjects at risk of hypovitaminosis D; the need or not to evaluate baseline serum 25(OH)D in candidate subjects for pharmacological treatment for osteoporosis; how and whether to supplement vitamin D subjects with hypovitaminosis D or candidates for pharmacological treatment with bone active agents, and the general population; how and whether to supplement vitamin D in chronic kidney disease and/or chronic liver diseases or under treatment with drugs interfering with hepatic metabolism; and finally, if vitamin D may have toxic effects in the subject in need of supplementation.