Alfacalcidol vs Calcitriol in the Management of Patient With Hypoparathyroidism: A Randomized Controlled Trial

Hypoparathyroidism: Similarities and differences between Western and Eastern countries

BACKGROUD

Hypoparathyroidism (hypoPT) is characterized by acute and chronic complications due to insufficient parathyroid hormone (PTH) production or action. Several management guidelines have been developed, but mostly based on evidence from Western countries. Data from Eastern countries have not been systematically compared with those from Western countries.

METHODS

Literatures regarding to the epidemiology, genetics, risk factors, clinical manifestations and therapies for hypoPT in Easten and Western countries, including China, South Korea, Japan, India, and USA, Canada, Italy, and etc., were searched through PubMed and CNKI. This review was officially endorsed by European Calcified Tissue Society (ECTS) board.

RESULTS

Postoperative hypoPT is the major form of hypoPT in both Western and Eastern countries. The genetic profiles and clinical features of hypoPT are similar in Eastern and Western countries. The most commonly used medications in Eastern countries are calcium and native vitamin D or active vitamin D analogues, similar to their Western counterparts. While PTH replacement therapy is not available and approved to use in most Eastern countries.

CONCLUSION

Physicians and surgeons should follow the guidelines on the management of thyroid nodules, taking more care of protecting parathyroid glands during surgery. The cross-talk between East and West in the management of hypoPT should be continued. Direct comparisons of the management strategies in patients with hypoPT between Eastern and Wester countries regarding to the morbidity, mortality, quality of life, optimal dosage, efficacies and side-effects of conventional therapies or newer medications, as well as pharmacogenetics and pharmacoeconomics, would be valuable.

Efficacy of Alfacalcidol Versus Calcitriol in Managing Secondary Hyperparathyroidism in Patients With Chronic Kidney Disease

Background: Data comparing the efficacy of alfacalcidol to that of calcitriol in managing secondary hyperparathyroidism in patients with chronic kidney disease (CKD) is scarce. We sought to compare the efficacy of both drugs in managing hyperparathyroidism in patients with CKD. Methods: A retrospective observational cohort study conducted from January 2022 to March 2023 included adults with CKD stages 3 to 5 (non-dialysis) who received alfacalcidol for 3 months followed by calcitriol for another 3 months. Assessments were done at baseline and after 3 months of each treatment. The primary outcome was iPTH suppression, and the secondary outcome was total serum calcium levels. Results: A total of 70 patients were included, with 34 (48.6%) being male. The cohort's mean age was 65.5 ± 15 years. CKD stage 3 comprised 47.1% of the sample. The median dose of alfacalcidol was 0.5 (0.25-0.8) µg compared to 0.5 (0.25-0.5) µg for calcitriol (P = .001). Alfacalcidol did not significantly suppress iPTH levels, with median values of 13.31 (8.23-24.4) pg/mL at baseline and 12.5 (8.86-24.7) pg/mL after 3 months (P = .937). In contrast, calcitriol significantly reduced iPTH levels from 12.5 (8.86-24.7) pg/mL to 10.7 (5.7-19) pg/mL (P = .017). Additionally, alfacalcidol did not significantly increase calcium levels, while calcitriol did. Throughout the study period, albumin values, the follow-up times, and the use of phosphate binders or non-active vitamin D remained consistent for each drug. The multivariate Generalized Estimating Equations indicated that baseline iPTH [B = 0.041, 95% CI (0.03- 0.05); P < .001], calcitriol [B = -0.278, 95% CI (-0.5 to -0.06); P = .014], daily dose of the study drug [B = -0.45, 95% CI (-0.7 to -0.2); P < .001], and baseline phosphorus level [B = 0.354, 95% CI (0.004-0.7); P = .047] were independent factors associated with iPTH suppression. Conclusion: Calcitriol, at significantly lower doses, was more effective than alfacalcidol in suppressing iPTH levels and increasing calcium levels over 3 months. A randomized controlled study is needed to confirm these findings.

Kenny-Caffey Syndrome Type 2 (KCS2): A New Case Report and Patient Follow-Up Optimization

Background/Objectives: Kenny-Caffey syndrome 2 (KCS2) is a rare cause of hypoparathyroidism, inherited in an autosomal dominant mode, resulting from pathogenic variants of the FAM111A gene, which is implicated in intracellular pathways regulating parathormone (PTH) synthesis and skeletal and parathyroid gland development. Methods: The case of a boy is reported, presenting with the characteristic and newly identified clinical, biochemical, radiological, and genetic abnormalities of KCS2. Results: The proband had noticeable dysmorphic features, and the closure of the anterior fontanel was delayed until the age of 4 years. Biochemical evaluation at several ages revealed persistent hypocalcemia, high normal phosphorous, and inappropriately low normal PTH. To exclude other causes of short stature, the diagnostic approach revealed low levels of IGF-1, and on CNS MRI, small pituitary gland and empty sella. Nocturnal levels of growth hormone were normal. MRI also revealed bilateral symmetrical microphthalmia and torturous optic nerves. Skeletal survey was compatible with cortical thickening and medullary stenosis of the long bones. Genomic data analysis revealed a well-known pathogenic variant of the FAM111A gene (c.1706G>A, p. R569H), which is linked with KCS2 or nanophthalmos. Conclusions: KCS2, although a rare disease, should be included in the differential diagnosis of hypoparathyroidism and short stature. Understanding the association of pathogenic variants with KCS2 phenotypic variability will allow the advancement of clinical genetics and personalized long-term follow-up and will offer insights into the role of the FAM111A gene in the disease pathogenesis and normal embryogenesis of implicated tissues and organs.

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.