Diabetic nephropathy (DN) is a specific kidney involvement in diabetes mellitus (DM), caused by hemodynamic and metabolic factors. In the kidneys takes place an important step in the metabolism of vitamin D — 1α-hydroxylation, which results in the formation of its biologically active form. Reduced number of functioning nephrons in DN leads to impaired vitamin D metabolism, contributing to the development of a number of complications. In this review, we have focused in detail on both normal vitamin D metabolism and the features of vitamin D metabolism in chronic kidney disease (CKD). DN is the most common cause of CKD and, as a consequence, of kidney transplantation and one of the leading causes of cardiovascular morbidity and mortality in patients with DM. Bone mineral disorders resulting from abnormal vitamin D metabolism are also independent factors of high mortality among patients with DM. The final part of our review briefly highlights current approaches to vitamin D therapy in CKD and, in particular, in DN. It is worth noting that, despite the increasing number of patients with DN, there is currently no unified view on the use of vitamin D as a therapeutic agent in this pathology.

AIM: The purpose of this study was to analyze the characteristics of management, diagnosis and treatment of patients with vitamin D deficiency/ by endocrinologists in the regions of Russian Federation using a sociological survey.MATERIALS AND METHODS: A cross-sectional sociological uncontrolled study was carried out. To implement this work, we used an online questionnaire “Questioning doctors on vitamin D” specially developed on the basis of the Google forms platform. The study was conducted in January 2021.All the data obtained were entered into an electronic database in MS Excel. Statistical processing was performed using the IBM SPSS Statistics 25 software.RESULTS: The survey involved 707 physicians from 86 regions of the Russian Federation. Our study revealed that not all doctors strictly adhere to clinical recommendations in patient management. Issues identified include unjustifiably widespread ordering of 25(OH)D blood tests (58.5%), lack of consideration for individual patient characteristics and clinical situations in dose selection (99.2%) and prescription of active metabolite or analogs of vitamin D to correct low 25(OH)D levels in blood (14.7%). Furthermore, recommendations for improving clinical guidelines focused on the lack of illustrative material (21.1%), expanding patient information sections (20.7%), and insufficient coverage of issues arising in clinical practice (14.6%). Our study also highlighted limited capabilities of laboratory diagnostics for assessing vitamin D status in patients in Russia. The survey revealed that only 9.2% of respondents have the ability to measure 1,25(OH)2D concentrations, and only 1.4% can order tests for 24,25(OH)2D. About 8.3% of participants did not specify which tests for assessing vitamin D status are available for prescription. Technical enhancement of laboratories and the inclusion of all recommended laboratory study requirements in the compulsory health insurance system could address this.Regarding vitamin D toxicity, 25% of surveyed doctors encountered it. Main causes included self-administration of elevated doses of cholecalciferol by patients (62%) or prescribed by physicians (40%), the use of active metabolites or analogs of vitamin D (21%), incorrect dosing of cholecalciferol preparations as indicated by the manufacturer (18%), and defects in CYP24A1 (13%). Rare causes included granulomatous and lymphoproliferative diseases (11.5%).CONCLUSION: The current clinical guidelines of the Russian Association of Endocrinologists for «Vitamin D Deficiency in Adults» are generally effective and widely used by clinicians. However, they do not entirely meet the needs of specialists and require refinement in terms of improving structure and clarity of presentation, expanding illustrative material, and justifying the frequency of laboratory diagnostics. Cases of vitamin D toxicity observed in clinical practice were predominantly associated with incorrect administration of vitamin D supplements. The identified high frequency of vitamin D toxicity in real clinical practice necessitates additional attention to this issue during the update of clinical recommendations.

Patients with multiple complications of diabetes mellitus often have significant deviations in the parameters of calcium-phosphorus and bone metabolism. The multifactorial nature of the pathogenesis of such disorders makes it difficult to manage patients with a long and complicated course of diabetes mellitus. This article describes a clinical case of a patient with a long history of type 1 diabetes mellitus, kidney transplantation as a result of terminal renal failure, and diabetic neuroosteoarthropathy. The features of vitamin D metabolism, the importance of timely diagnosis of phosphorus-calcium disorders and the features of patient therapy are discussed.

ASBMR 2022 Annual Meeting and Vitamin D Workshop 2022 — the key international events in the field of metabolic diseases of the skeleton and pathology of mineral metabolism — were held in September 2022. During the conferences the results of the latest research were presented, promising areas of further research were discussed, as well as debates and author’s sessions on controversial issues were held. The article provides a brief overview of the events.

Patients with chronic kidney disease are characterized by the development of mineral disorders due to a decrease in the number of functioning nephrons. These changes manifest by the development of secondary hyperparathyroidism (the overproduction of intact parathyroid hormone (PTH) associated with the serum hypocalcemia, hyperphosphatemia), dysfunctional vitamin D metabolism, bone mineralization and also extraosseous calcifications. Decreased serum PTH levels associated with hypercalcemia are suspicious for adynamic bone disease, but at the same time requires an extended differential diagnostic search (e.g. metastatic processes). One of the rare causes of hypercalcemia is a defect in 24-hydroxylase (CYP24A1). We present a case of a patient on hemodialysis with atypical secondary hyperparathyroidism and an established CYP24A1 defect.

This draft clinical practice guideline for the diagnosis, treatment and prevention of vitamin D deficiency is an update from a previous 2016 document. An analysis of the relevant literature data was carried out, with particular attention to meta-­analyzes, randomized clinical trials and systematic reviews published over the past 5 years. The updated recommendations were discussed and revised by the leading endocrinologists of the Russian Federation, who have expert status in this issue.The classification of 25(OH)D levels has been revised (in particular, the target range of 25(OH)D values has been specified), recommendations have been developed for screening of the disorders associated with vitamin D deficiency. The concept of vitamin D-associated toxicity and recommendations for its diagnosis and prevention have been introduced. Also, indications for the assessment of other vitamin D metabolites besides 25(OH)D, the main marker of vitamin D status, have been indicated.The section regarding treatment of vitamin D deficiency has been expanded and corrected. The major additions concerned the replenishment of the vitamin D deficiency and insufficiency in certain categories of patients (particularly, in the presence of the chronic kidney disease and autoimmune diseases, as well as in pregnant women) and monitoring of the effectiveness and safety of the therapy. The indications for prescribing active metabolites of vitamin D have been adjusted. Recommendations for the prevention of vitamin D deficiency in the general population have also been revised, taking into account large randomized clinical trials, meta-analyzes and systematic reviews of recent years.This publication is an expanded version of the federal guidelines.

IV (XXVII) Национальный конгресс эндокринологов с международным участием «ИННОВАЦИОННЫЕ ТЕХНОЛОГИИ В ЭНДОКРИНОЛОГИИ» 22-25 сентября 2021 года НАРУШЕНИЕ МЕТАБОЛИЗМА ВИТАМИНА D У ГОСПИТАЛИЗИРОВАННЫХ ПАЦИЕНТОВ С COVID-19 Поваляева А .А ., Богданов В