Serum 1,25-Dihydroxyvitamin D as a Biomarker of the Absence of Hypercalciuria in Postsurgical Hypoparathyroidism

Parameters of Vitamin D Metabolism in Patients with Hypoparathyroidism

Only a few studies evaluating the metabolism of vitamin D in patients with hypoparathyroidism (HypoPT) have been performed thus far, and, in particular, they mainly investigated the process of vitamin D activation (specifically, 1α-hydroxylation). This study, therefore, aimed to evaluate the extended spectrum of vitamin D metabolites in patients with HypoPT compared to healthy individuals. We examined 38 adult patients with chronic HypoPT in comparison to 38 healthy adults. The assessment included biochemical parameters (total calcium, albumin, phosphorus, creatinine, and magnesium), parathyroid hormone (PTH), and vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3, and 24,25(OH)2D3) in serum. Our data show that an adequate level of 25(OH)D3 (median 35.3 (29.6; 42.0) ng/mL) is achieved with standard doses of cholecalciferol (median 2000 (2000; 2500) IU per day) in HypoPT patients. They also presented with supraphysiological levels of 1,25(OH)2D3 (median 71 (47; 96) vs. 40 (34; 59) pg/mL, p < 0.001) and the increased production of inactive metabolite (median 24,25(OH)2D3 3.8 (3.0; 5.1) vs. 1.9 (1.3; 2.7) ng/mL, p < 0.001; median 25(OH)D3/24,25(OH)2D3 ratio 8.9 (7.6; 11.1) vs. 13.5 (11.1; 17.0), p < 0.001) as compared to the control group. This might be a consequence of the therapy received (treatment with activated vitamin D) and the pathophysiology of the disease (lack of PTH). The abnormality of vitamin D metabolism does not seem to interfere with the achievement of hypoparathyroidism compensation.

Epidemiology and Financial Burden of Adult Chronic Hypoparathyroidism

Chronic hypoparathyroidism is characterized by low serum calcium, increased serum phosphorus, and inappropriately low or decreased serum parathyroid hormone. This rare disorder is associated with a variety of complications. The prevalence, incidence, mortality, financial burden, and epidemiology of complications of this disorder are not well understood. This narrative review summarizes current information on the epidemiology and complications of chronic hypoparathyroidism. The reported prevalence of chronic hypoparathyroidism ranges from 6.4-37/100,000, and the incidence is reported to be 0.8-2.3/100,000/year. Mortality is not increased in studies from Denmark or South Korea but was increased in studies from Scotland and Sweden. The financial burden of this disorder is substantial because of increased health care resource utilization in two studies but not well quantitated. Recognized complications include hypercalciuria, nephrocalcinosis, kidney stones, and chronic kidney disease; low bone turnover and possibly upper extremity fractures; cardiac and vascular calcifications; basal ganglia calcifications, cataracts, infections, neuropsychiatric complications, and difficulties with pregnancy. This review concludes that chronic hypoparathyroidism is a rare disorder associated with significant morbidity that may not increase overall mortality but is associated with a substantial financial burden. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

[Evaluation of chronic hypoparathyroidism course according to the Database of Endocrinology Research Centre]

BACKGRAUND

Currently high frequency of thyroid or parathyroid surgery is associated with significant increased incidence of hypoparathyroidism. Evaluation of the epidemiological and clinical features of chronic hypoparathyroidism is necessary to predict social-significant complications and to improve the quality of medical care.

AIMS

To estimate clinical and demographic features, different regimens and efficacy of conventional therapy in patients with chronic postsurgical and nonsurgical hypoparathyroidism.

MATERIALS AND METHODS

The cross-sectional, observational, continuous study was carried out based on Database of patients with chronic postsurgical and nonsurgical hypoparathyroidism of Endocrinology Research Centre, Moscow. 293 patients from 61 regions of the Russian Federation were included in this study. Statistical analysis was done on June 2020. The descriptive statistics are presented by medians (Ме) and the first and third quartiles (Q1; Q3) and by absolute and relative frequencies.

RESULTS

Hypoparathyroidism was most often recorded in women (85%) at the age of 43 [32; 52] years, after thyroid surgery. Less than a half of the study group had target indicators of serum calcium and phosphate levels (31% and 47%, respectively) despite ongoing treatment. A complex instrumental examination for the disease complications was performed in 58% of cases (n = 169). Among them, kidney disorders were detected in 38%, visual disturbance in 14%, brain calcification in 10%, arrhythmias in 4% and neuropsychiatric symptoms in 6%. Conventional therapy with calcium supplements and activated vitamin D analogues was noted in 75% of patients.

CONCLUSIONS

The analysis of large databases of patients with chronic hypoparathyroidism is a necessary tool for determining of optimal clinical and therapeutic approaches, as well as prognostic markers of disease complications.

Auditing the Efficacy and Safety of Alfacalcidol and Calcium Therapy in Idiopathic Hypoparathyroidism

CONTEXT

Patients with hypoparathyroidism are treated with vitamin D and calcium. PTH is an emerging option because of its physiological action. It is important to assess the efficacy and shortcomings of conventional therapy.

OBJECTIVE

We assessed the efficacy and safety of alfacalcidol in a large cohort of patients with idiopathic hypoparathyroidism (IH) and identified a subset who could be treated without oral calcium.

DESIGN AND SETTING

Observational study at tertiary care center.

SUBJECTS AND METHODS

We assessed 92 patients with IH who were receiving alfacalcidol and oral calcium to maintain an optimal serum total calcium level of 8.0 to 8.5 mg/dL during routine follow-up. Patients with suboptimal control were provided free medicines and followed up frequently. Oral calcium and alfacalcidol doses were titrated sequentially to determine the minimum doses for optimal calcium control. Serum phosphate level, 1,25-dihydroxyvitamin D, fractional excretion of phosphorus (FEPh), and hypercalciuria (urine calcium-to-creatinine ratio, >0.2) were assessed at each step of titration.

RESULTS

Only 38% of patients had optimal calcium control during routine follow-up. With good compliance, all achieved optimal serum calcium and 1,25-dihydroxyvitamin D levels and 43% of patients could stop taking oral calcium. Hyperphosphatemia, hypercalciuria, and low FEPh persisted at all stages of therapy. Serum phosphorus levels normalized when the serum calcium level increased to 9.9 mg/dL, but this level of serum total calcium was associated with hypercalciuria in 90% of patients.

CONCLUSION

Alfacalcidol is effective in achieving calcemic control in IH. Calcemic control without oral calcium was achieved in 43% of patients receiving alfacalcidol. However, optimal calcium control was associated with hyperphosphatemia and hypercalciuria in most patients.