Albumin-adjusted Serum Calcium Research Articles

An Open-Label Phase 2 Study of Eneboparatide, a Novel PTH Receptor 1 Agonist, in Hypoparathyroidism.

Hypoparathyroidism is a rare disorder characterized by a deficiency in parathyroid hormone (PTH) resulting in hypocalcemia, hyperphosphatemia, and hypercalciuria. Eneboparatide is an investigational peptide agonist of the PTH1 receptor for the treatment of chronic hypoparathyroidism (HP). To evaluate the efficacy, safety, and tolerability of eneboparatide in HP patients. Open-label, phase 2 study. Twenty-eight patients (21 women, 7 men), mean age (range): 58 years (28-72), with HP were enrolled into 2 consecutive cohorts (C1, n = 12, and C2, n = 16). Following an optimization period, daily subcutaneous injections of eneboparatide were administered for 3 months at 20 µg/day (C1) or 10 µg/day (C2) starting dose. Conventional therapy was progressively removed and eneboparatide could be titrated up to 60 µg (C1) or 80 µg (C2). Proportion of patients achieving independence from conventional therapy, albumin-adjusted serum calcium (ADsCa), 24-h urine calcium (uCa), serum bone turnover markers (s-CTX and P1NP), bone mineral density (BMD), and adverse events (AEs). After 3 months, ≥ 88% patients achieved independence from conventional therapy while mean ADsCa was maintained within target range (7.8-9 mg/dL). Eneboparatide induced a rapid and sustained reduction of mean 24-hour uCa, even among patients with hypercalciuria. Bone turnover markers slightly increased and BMD remained unchanged, consistent with progressive resumption of physiologic bone turnover. Eneboparatide was well tolerated with no serious AEs. Eneboparatide allowed independence from conventional therapy and maintenance of serum calcium within a target range, while normalizing uCa excretion and producing a balanced resumption of bone turnover.

Independent associations of serum calcium with or without albumin adjustment and serum phosphorus with nonalcoholic fatty liver disease: results from NHANES 1999-2018.

The associations of serum calcium and phosphorus with nonalcoholic fatty liver disease (NAFLD) remain unclear. In addition, there may be an effect of albumin correction on the association between serum calcium and NAFLD. We aimed to explore these relationships in the National Health and Nutrition Examination Survey (NHANES). Eligible adult individuals from NHANES 1999-2018 were recruited for the study. We explored the associations of serum calcium, albumin-adjusted serum calcium, and serum phosphorus with NAFLD in multivariable-adjusted regression models. In addition, restricted cubic spline (RCS), stratified analysis, and multiple sensitivity analyses were used for further elaboration. The study sample consisted of 20,900 participants, with an observed NAFLD prevalence of 44.65%. Fully adjusted models indicated that serum calcium was inversely associated with NAFLD (odds ratio [OR] and 95% confidence interval [CI] = 0.70 (0.62, 0.78), p<0.0001), whereas albumin-adjusted serum calcium was positively associated with NAFLD (OR and 95% CI=1.59 (1.41, 1.79), p<0.0001). RCS modeling indicated that serum calcium without and with albumin adjustment was linearly(p nonlinear = 0.083) and nonlinearly (p nonlinear < 0.0001) associated with NAFLD, respectively, whereas serum phosphorus showed a U-shaped relationship with NAFLD(p nonlinear < 0.0001). Gender is a significant influence in all associations, and other variables may also have an effect. Sensitivity analyses indicated that these associations were independent of additional significant confounders. Serum calcium and phosphorus were significantly associated with the development of NAFLD. These findings suggest the potential clinical significance of serum calcium/phosphorus and albumin levels in individuals at high risk for NAFLD. Our study supports the potential role of serum calcium/phosphorus homeostasis in the pathophysiology of NAFLD and could serve as NAFLD-related biomarkers.

Denosumab-induced hypocalcemia in patients with solid tumors and renal dysfunction: a multicenter, retrospective, observational study

BackgroundBone metastases are frequently observed in advanced cancer, and bone modifying agents are used to prevent or treat skeletal-related events. Zoledronic acid is contraindicated in patients with severe renal impairment (Ccr < 30 mL/min), but it is not completely known whether denosumab can be used in them. We aimed to determine the association between renal function and hypocalcemia development during denosumab treatment.MethodsWe included patients with solid cancer and bone metastases who started denosumab treatment between April 2017 and March 2019. They were classified into four groups based on creatinine clearance (Ccr; mL/min): normal (Ccr ≥ 80), mild (50 ≤ Ccr ˂80), moderate (30 ≤ Ccr ˂50), and severe (Ccr ˂30). Hypocalcemia was evaluated using the Common Terminology Criteria for Adverse Events (v5.0) based on the albumin-adjusted serum calcium levels; its incidence (stratified by renal function) and risk factors were investigated using a Chi-square test and logistic regression analysis.ResultsOf 524 patients (age: 69 ± 11 years; 303 men), 153 had a normal renal function and 222, 117, and 32 had mild, moderate, and severe renal dysfunction. The albumin-adjusted serum calcium level was higher than the measured (total) calcium level in most patients. The incidence of grade ≥ 1 hypocalcemia was 32.0% in the normal group and 37.4%, 29.9%, and 62.5% in the mild, moderate, and severe renal dysfunction groups, respectively. It was, therefore, higher in the severe renal dysfunction groups than in the normal group (P = 0.002). The incidence of grade ≥ 3 hypocalcemia did not differ significantly among the groups. Pre-treatment low serum calcium levels and severe renal dysfunction were risk factors for hypocalcemia.ConclusionsEvaluating denosumab-induced hypocalcemia required albumin adjustment, and its incidence was high among patients with severe renal dysfunction. Reduced serum calcium levels and severely impaired renal function were associated with an elevated hypocalcemia risk.

The daily calcium profile in patients with chronic hypoparathyroidism depending on different 25(OH) vitamin D level

BACKGROUND: Chronic hypoparathyroidism is a relatively rare disease, which usually treated active forms of vitamin D and oral calcium supplements. Supplementation with native vitamin D can be useful both for achieving «non-skeletal» effects of vitamin D and for a more stable serum calcium profile.AIM: The aim of this study was to estimate the daily serum calcium and 24-hour urine calcium levels depending on different 25(OH) vitamin D values in patients with chronic hypoparathyroidism on treatment of active forms of vitamin D and calcium supplements.MATERIALS AND METHODS: Forty patients with chronic hypoparathyroidism were involved in the study. All patients were divided in two groups, matched on sex and age, according to the median level of 25(OH) vitamin D in the total group.RESULTS: There were no significant differences between groups by total, albumin-adjusted serum calcium levels and urine calcium excretion. Patients with serum 25(ОН) vitamin D level ≥ 35 ng/ml had significant tendency to achieve more often the target levels of total serum calcium during the day (128 vs. 149 measurements during the day, p=0.049, χ2). However, this tendency disappeared for albumin-adjusted serum calcium levels (p=0.517, χ2). There frequency of hypercalcemia by albumin-adjusted serum calcium in the group of patients with 25(ОН) vitamin D ≥ 35 ng/ml (p=0.006, χ2) was significantly lower, but not for total serum calcium (a trend, p=0.042, χ2). As regards hypocalcemia, there were no significant differences by albumin-adjusted serum calcium (p=0.581, χ2) and it tends to lower frequency by total serum calcium (p=0.023, χ2).CONCLUSION: The additional administration of native vitamin D in patients with chronic hypoparathyroidism may have some advantages, related to the general concept of worldwide vitamin D deficiency and better disease control.

Extended Treatment With Recombinant Human Parathyroid Hormone (1-84) in Adult Patients With Chronic Hypoparathyroidism

ObjectiveRecombinant human parathyroid hormone (1-84) (rhPTH[1-84]) is efficacious in patients with hypoparathyroidism but additional data supporting its prolonged use are needed. We evaluated whether efficacy, safety, and tolerability are maintained during long-term rhPTH(1-84) treatment of patients with chronic hypoparathyroidism. MethodsThis was a phase 4, single-center, open-label, single-arm, 3-year extension (NCT02910466) of the phase 3 Hypo Extended (HEXT) study (NCT01199614). Patients self-administered rhPTH(1-84) once daily by subcutaneous injection, with doses individualized based on clinical parameters. Albumin-adjusted serum calcium levels (primary outcome measure), other disease biomarkers, health-related quality of life, and safety of rhPTH(1-84) were assessed using descriptive statistics. ResultsAll patients (n = 39) had been exposed to rhPTH(1-84) (mean exposure [SD] 8.5 [3.5] years) before the start of the study, resulting in a mean exposure of 10.8 years including the present study. Mean patient age was 51.9 years, 79.5% were female, and 97.4% were White. Mean albumin-adjusted serum calcium concentrations were within the target range, and mean serum phosphate, serum calcium-phosphate product, and 24-hour urinary calcium excretion levels were within reference ranges at end of treatment. Mean doses of supplemental calcium and active vitamin D were maintained throughout the study. Bone turnover marker levels were maintained from baseline to end of treatment. No clinically relevant changes in bone mineral density were observed. Patient-reported health-related quality-of-life scores were generally maintained throughout the study. Four adverse events were considered treatment related and no new safety signals were identified. ConclusionThe effects of rhPTH(1-84) on biochemical, skeletal, and health-related quality-of-life parameters did not wane with extended use.

SAT237 AZP-3601, A Novel PTH 1 Receptor Agonist, Induces Rapid Reduction And Normalization Of Urinary Calcium In Chronic Hypoparathyroid Patients

Abstract Disclosure: L. Figueres: None. I. Takacs: None. E. Mezosi: None. A. Soto: None. P. Kamenicky: None. S. Lemoine: None. F. Borson-Chazot: None. I. Capel: None. M.A. Galvez moreno: None. M. Ovize: Employee; Self; employee. T. OuldRouis: Employee; Self; employee. S. allas: Employee; Self; employee. M. Sumeray: Employee; Self; employee. M. Mannstadt: Consulting Fee; Self; consultant. Background: Conventional therapy with oral calcium (Ca) and active vitamin D (vitD) supplementation for chronic hypoparathyroidism (cHP) can induce or aggravate hypercalciuria and may lead to detrimental long-term renal complications. AZP-3601 is a novel 36-amino-acid peptide designed to activate the R0 conformation of the PTH 1 receptor which produces a prolonged calcemic response despite a short half-life. This phase 2 study examined the effects of AZP-3601 on urinary Ca (uCa) excretion in two consecutive cohorts (C1 and C2) of cHP patients. Methods: Following an optimization period, during which Ca and active vitD doses were adjusted to achieve baseline albumin-adjusted serum calcium within the target range of 7.8 to 9.0 mg/dL, patients received a daily sc. injection of AZP-3601 at initial doses of 20 µg/day (C1) or 10 µg/day (d) (C2), while simultaneously reducing their Ca and active vitD . Subsequent up-titration to a maximum daily dose of 60 µg (C1) or 80 µg(C2) was allowed. Twenty-four-hour urinary Ca excretion (24h-uCa), fractional excretion of Ca (FECa), 24h-urinary phosphate (24h-uP), serum phosphate (sP) were assessed at baseline and at D84. Pooled data from 24 patients who completed the study are presented here. Results: Twenty-four patients (18 women) aged (SD) 56(11) years were taking 0.61(0.26) µg/d active vitD and 1733(1442) mg oral Ca at baseline. At D84 , active vitD and oral Ca were each discontinued in 88% of patients, while mean albumin-adjusted serum calcium remained within the target range. Mean 24h-uCa decreased from 325(172) mg/24h to 207(107) mg/24h and 130(91) mg/24h at D14 and D84, respectively. In 13 patients with hypercalciuria at baseline, we observed a 67% reduction of 24h-uCa at D84 and a normalization of 24h-uCa in 92% of them. From baseline to D84, mean FECa decreased in the entire population and in patients with hypercalciuria. Between baseline to D84, 24h-uP excretion increased from 721(331) mg/24h to 794(238) mg/24h while mean sP decreased from 4.3(0.8) mg/dL to 3.7(0.6) mg/dL. Conclusion: These data demonstrate that AZP-3601 treatment maintained sCa within the target range after withdrawal of conventional therapy likely acting via a potent effect on the tubular reabsorption of calcium. The observed significant improvement in both uCa and sP is expected to translate to a clinically meaningful benefit for cHP patients in the long-term. Presentation: Saturday, June 17, 2023

OR23-05 Log-term Efficacy And Safety Of Transcon PTH In Adults With Hypoparathyroidism: 52-week Results From The Open-label Extension Of The Phase 3 Pathway Trial

OR23-05 Log-term Efficacy And Safety Of Transcon PTH In Adults With Hypoparathyroidism: 52-week Results From The Open-label Extension Of The Phase 3 Pathway Trial

Threshold of 25(OH)D and consequently adjusted parathyroid hormone reference intervals: data mining for relationship between vitamin D and parathyroid hormone

PurposeBy recruiting reference population, we aimed to (1): estimate the 25(OH)D threshold that maximally inhibits the PTH, which can be defined as the cutoff value for vitamin D sufficiency; (2) establish the PTH reference interval (RI) in population with sufficient vitamin D.MethodsStudy data were retrieved from LIS (Laboratory Information Management System) under literature suggested criteria, and outliers were excluded using Tukey fence method. Locally weighted regression (LOESS) and segmented regression (SR) were conducted to estimate the threshold of 25(OH)D. Multivariate linear regression was performed to evaluate the associations between PTH concentration and variables including 25(OH)D, gender, age, estimated glomerular filtration rate (EGFR), body mass index (BMI), albumin-adjusted serum calcium (aCa), serum phosphate(P), serum magnesium(Mg), and blood collection season. Z test was adopted to evaluate whether the reference interval should be stratified by determinants such as age and gender.ResultsA total of 64,979 apparently healthy subjects were recruited in this study, with median (Q1, Q3) 25(OH)D of 45.33 (36.15, 57.50) nmol/L and median (Q1, Q3) PTH of 42.19 (34.24, 52.20) ng/L. The segmented regression determined the 25(OH)D threshold of 55 nmol/L above which PTH would somewhat plateau and of 22 nmol/L below which PTH would rise steeply. Multivariate linear regression suggested that gender, EGFR, and BMI were independently associated with PTH concentrations. The PTH RI was calculated as 22.17–72.72 ng/L for subjects with 25(OH)D ≥ 55 nmol/L with no necessity of stratification according to gender, age, menopausal status nor season.ConclusionThis study reported 25(OH)D thresholds of vitamin D sufficiency at 55 nmol/L and vitamin D deficiency at 22 nmol/L, and consequently established PTH RIs in subjects with sufficient vitamin D for northern China population for the first time.

Long-Term Safety and Efficacy of Recombinant Human Parathyroid Hormone (1-84) in Adults With Chronic Hypoparathyroidism.

Chronic hypoparathyroidism is conventionally treated with oral calcium and active vitamin D to reach and maintain targeted serum calcium and phosphorus levels, but some patients remain inadequately controlled. To assess long-term safety and efficacy of recombinant human parathyroid hormone (1-84) (rhPTH(1-84)) treatment. This was an open-label extension study at 12 US centers. Adults (n = 49) with chronic hypoparathyroidism were included. The intervention was rhPTH(1-84) for 6 years. The main outcome measures were safety, biochemical measures, oral supplement doses, bone indices. Thirty-eight patients (77.6%) completed the study. Throughout 72 months, mean albumin-adjusted serum calcium was within 2.00 to 2.25 mmol/L (8.0-9.0 mg/dL). At baseline, 65% of patients with measurements (n = 24/37) were hypercalciuric; of these, 54% (n = 13/24) were normocalciuric at month 72. Mean serum phosphorus declined from 1.6 ± 0.19 mmol/L at baseline (n = 49) to 1.3 ± 0.20 mmol/L at month 72 (n = 36). Mean estimated glomerular filtration rate was stable. rhPTH(1-84)-related adverse events were reported in 51.0% of patients (n = 25/49); all but 1 event were mild/moderate in severity. Mean oral calcium supplementation reduced by 45% ± 113.6% and calcitriol by 74% ± 39.3%. Bone turnover markers declined by month 32 to a plateau above pretreatment values; only aminoterminal propeptide of type 1 collagen remained outside the reference range. Mean bone mineral density z score fell at one-third radius and was stable at other sites. 6 years of rhPTH(1-84) treatment was associated with sustained improvements in biochemical parameters, a reduction in the percentage of patients with hypercalciuria, stable renal function, and decreased supplement requirements. rhPTH(1-84) was well tolerated; no new safety signals were identified.

39P Longitudinal increases in albumin-adjusted serum calcium predict ovarian cancer

39P Longitudinal increases in albumin-adjusted serum calcium predict ovarian cancer

The Predictive Value of Serum Calcium on Heart Rate Variability and Cardiac Function in Type 2 Diabetes Patients.

BackgroundCardiovascular autonomic neuropathy (CAN) is common in patients with type 2 diabetes mellitus (T2DM), mainly presented as decreased heart rate variability (HRV) which often leads to cardiac death. However, HRV measurement is not convenient in most clinics. Therefore, identifying high-risk patients for CAN in diabetes with easier measurements is crucial for the early intervention and prevention of catastrophic consequences.MethodsIn this cross-sectional study, 675 T2DM patients with normocalcemia were selected. Of these, they were divided into two groups: normal HRV group (n = 425, 100 ms≤ SDNN ≤180 ms) vs. declined HRV group (n = 250, SDNN <100 ms). All patients’ clinical data were collected and the correlation of clinical variables with HRV were analyzed by correlation and logistic regression analysis. The area below the ROC curve was used to evaluate the predictive performance of serum calcium on HRV.ResultsIn this study, declines in HRV were present in 37.0% of T2DM patients. Significant differences in albumin-adjusted serum calcium levels (CaA) (8.86 ± 0.27 vs. 9.13 ± 0.39 mg/dl, p <0.001) and E/A (0.78 ± 0.22 vs. 0.83 ± 0.26, p = 0.029) were observed between declined HRV and normal HRV groups. Bivariate linear correlation analysis showed that CaA and E/A were positively correlated with HRV parameters including SDNN (p < 0.001), SDNN index (p < 0.001), and Triangle index (p < 0.05). The AUC in the ROC curve for the prediction of CaA on HRV was 0.730 (95% CI (0.750–0.815), p < 0.001). The cutoff value of CaA was 8.87 mg/dl (sensitivity 0.644, specificity 0.814). The T2DM patients with CaA <8.87 mg/dl had significantly lower HRV parameters (SDNN, SDNN index, rMSSD, and triangle index) than those with CaA ≥8.87 mg/dl (p < 0.01, respectively). Multivariate logistic regression analysis showed a significantly increased risk of declined HRV in subjects with CaA level <8.87 mg/dl [OR (95% CI), 0.049 (0.024–0.099), p < 0.001].ConclusionsDeclined HRV is associated with a lower CaA level and worse cardiac function. The serum calcium level can be used for risk evaluation of declined HRV in T2DM patients even within the normocalcemic range.

Hypercalcemia in a Patient Treated With Abaloparatide

Abstract Introduction: The antifracture efficacy of newer agents like PTHrP analogues is promising but knowledge about the mechanism of action and safety profile is needed in order to use these agents effectively. The reported incidence of hypercalcemia defined as albumin-adjusted serum calcium ≥10.7mg/dL was 3.4% in Abaloparitide. Case Presentation: A 59 year-old female with past medical history significant for diabetes mellitus type 2, hypothyroidism, necrotizing autoimmune myositis, osteoporosis and renal stones presented with complaints of generalized body aches and pains with swelling and redness of the left leg. The patient was diagnosed with osteoporosis based on atraumatic L4 compressive injury involving superior end plate. Her only DXA scan was 8 years ago which showed osteopenia, with the lowest T score of -1.2 at lumbar spine. Subsequent evaluation with DXA scan was unable to be performed due to physical disabilities. She was intolerant to oral bisphosphonates and was started on abaloparatide subcutaneous injections 2 weeks prior to her current admission. Her physical examination was positive for obesity, proximal muscle weakness and bilateral leg edema with bruises and left leg erythema. Laboratory findings showed hypercalcemia with corrected calcium levels of 12.48 mg/dl, suppressed intact PTH 4 pg/ml. Evaluations for secondary causes of hypercalcemia were negative. Her last dose of abaloparatide injection was the morning prior to her presentation to the emergency room. The patient was treated with IV fluids and her calcium level improved within 24 hours with normalization of intact PTH level in 72hrs. Abaloparatide injection was suspended on admission. Hypercalcemia with suppressed PTH was most likely secondary to abaloparatide given the timing of the hypercalcemia after the injection and resolution of hypercalcemia and normalization of PTH. Conclusions: Abaloparatide is a peptide that selectively binds to the RG conformation of the parathyroid hormone type 1 receptor. Abaloparatide is increasingly used following the results from the ACTIVE and ACTIVExtend trials which demonstrate significant increase in bone mineral density and risk reduction of vertebral, nonvertebral, clinical, and major osteoporotic fractures. Hypercalcemia was reported as a side effect, but there is no guidance on further evaluation or management of these patients. The incidence of hypercalcemia defined as albumin-adjusted serum calcium ≥10.7mg/dL is 3.4 % and risk is increased in patients with renal impairment. As in our case, transient hypercalcemia and PTH suppression may be associated with abaloparatide. Efficacy of abaloparatide and impact on bone density with delay or interrupted treatment are not available. Further studies are needed to guide monitoring and treatment of clinically symptomatic transient hypercalcemia in patients taking abaloparatide.

A Single Administration of AZP-3601, a Novel, Long-Acting PTH Analog, Induces a Significant and Sustained Calcemic Response: Preliminary Data From a Randomized, Double-Blind, Placebo-Controlled Phase 1 Study

Hypoparathyroidism is a rare disease characterized by a deficiency in parathyroid hormone (PTH) that results in hypocalcemia and hyperphosphatemia. Current treatment approaches, including high dose oral calcium and active vitamin D, as well as recombinant human PTH (1–84), do not provide adequate or consistent control of either serum calcium or clinical symptoms over a full 24-hour period. AZP-3601 is a novel 36 amino-acid PTH analog that has been designed to potently bind to the R0 conformation of the PTH1 receptor, which results in prolonged signaling responses in vitro and prolonged calcemic responses in animals despite having a short circulating half-life. A Phase 1 double-blind, placebo-controlled, single and multiple ascending dose study is being conducted to evaluate the safety, tolerability and pharmacodynamics of AZP-3601 in healthy adults. Here we report data from the first cohorts of the single ascending dose portion of the study. Sequential cohorts of 4 (cohort 1) to 8 (cohort 2 to 4) healthy male subjects aged 18–60 years, with a body mass index of 19–28 kg/m2, were assigned to receive 5, 10, 20 or 40μg of AZP-3601 or placebo at a ratio of 3:1. The study drug was administered in the morning by subcutaneous injection in the abdominal wall and was well tolerated with no remarkable adverse events. As compared with placebo controls, AZP-3601 treatment produced a clear, dose-dependent increase in mean albumin-adjusted serum calcium values from baseline. The normal physiological diurnal variation of albumin-adjusted serum calcium was gradually attenuated with 5 and 10μg AZP-3601, and was completely eliminated with 20μg. With the dose of 40μg AZP-3601, mean albumin-adjusted serum calcium values were significantly increased but stayed within normal laboratory range and remained elevated through at least 24 hours post-administration. We observed a dose-dependent decrease in mean endogenous serum PTH that was significantly correlated with the concomitant increase in mean serum calcium. These data provide initial evidence of the pharmacodynamic effect of AZP-3601 in healthy humans characterized by a sustained calcemic response for at least 24 hours following a single administration.

Vitamin D Metabolism Is Significantly Impaired in COVID-19 Inpatients

Objective: to assess the state of vitamin D metabolism in patients hospitalized with COVID-19 infection. Materials and methods: We examined 49 patients, which were hospitalized for inpatient treatment of COVID-19 infection from May to June 2020. Study group included 24 men (49%) and 25 women (51%), median age 58 years [48; 70], BMI 26.4 kg/m2 [24.3; 30.5]. All patients were diagnosed with pneumonia due to SARS-CoV-2 with median percent of lung involvement equal to 29% [14; 37], 22 patients (45%) required oxygen support upon admission. Median SpO2 was equal to 95% (92; 97), median NEWS score was equal to 3 [2; 6]. Participants were tested for vitamin D metabolites (25(OH)D3, 1,25(OH)2D3, 3-epi-25(OH)D3, 24,25(OH)2D3 and D3) by UPLC-MS/MS, free 25(OH)D and vitamin D-binding protein by ELISA, as well as PTH by electrochemiluminescence immunoassay and routine biochemical parameters of blood serum (calcium, phosphorus, albumin) at the time of admission. Results: patients had in general very low 25()D3 levels - median 10.9 ng/mL [6.9; 15.6], corresponding to a pronounced vitamin D deficiency in half of the patients. Levels of 24,25(OH)2D3 were also low – 0.5 ng/mL [0.2; 0.9], and resulting vitamin D metabolite ratios (25(OH)D3/24,25(OH)2D3) were high-normal or elevated in most patients – 24.1 [19.0; 39.2], indicating decreased activity of 24-hydroxylase. Levels of 1,25(OH)2D3, on the contrary, were high-normal or elevated - 57 pg/mL [46; 79], which, in accordance with 25(OH)D3/1,25(OH)2D3 ratio (219 [134; 266]) suggests an increase in 1α-hydroxylase activity. Median level of 3-epi-25(OH)D3 was 0.7 ng/mL [0.4; 1.0] and D3 metabolite was detectable only in 6 patients. Median DBP level was 432 mg/L [382; 498], median free 25(OH)D was 5.6 pg/mL [3.3; 6.7], median calculated free 25(OH)D was 2.0 pg/mL [1.4; 3.3]. Most patients had albumin-adjusted serum calcium level in the lower half of reference range (median 2.24 mmol/L [2.14; 2.34]). Seven patients had secondary hyperparathyroidism and one patient had primary hyperparathyroidism, the rest of the patients had PTH levels within the normal range.25(OH)D3 levels showed significant negative correlation with percent of lung involvement (r = -0.36, p<0.05) and positive correlation with SpO2 (r = 0.4, p<0.05). 1,25(OH)2D3 levels correlated positively with 25(OH)D3 levels (r = 0.38, p<0.05) and did not correlate significantly with PTH levels (p>0.05). Conclusion: Our data suggests that hospitalized patients with COVID-19 infection have significant impairment of vitamin D metabolism, in particular, an increase in 1α-hydroxylase activity, which cannot be fully explained by pre-existing conditions such as vitamin D deficiency and secondary hyperparathyroidism. The observed profound vitamin D deficiency and association of vitamin D levels with markers of disease severity indicate the importance of vitamin D supplementation in these patients.

Prevalence of biochemical osteomalacia in adults undergoing vitamin D testing.

Prolonged severe vitamin D deficiency can cause osteomalacia, but the 25-hydroxyvitamin D (25OHD) concentration below which this occurs is unknown. We investigated the prevalence of biochemical osteomalacia in adults with a measurement of 25OHD. 25OHD results between 1/1/2009 and 15/6/2020 were obtained from the regional laboratory database, together with measurements of serum calcium, parathyroid hormone (PTH) and alkaline phosphatase (ALP) within 6months of the index 25OHD. We defined biochemical osteomalacia as all 3 of: albumin-adjusted serum calcium (aCa)<2.0mmol/L, PTH>7.3pmol/L and ALP>150IU/L. Possible osteomalacia was 2/3 criteria with the other test not done. 25OHD measurements associated with significant renal impairment, elevated hepatic transaminases or hypercalcaemia were excluded. 110,046 25OHD measurements were identified over the 11.5years period. After removal of ineligible measurements, 42,171 25OHD measurements from 32,386 individuals with at least 2 of aCa, PTH and ALP were included in analyses. Median 25OHD was 63nmol/L; 8% were <25nmol/L, and 33% were <50nmol/L. Five index 25OHD measurements met the definition of biochemical osteomalacia, and another 11 were possible osteomalacia. After reviewing available clinical records for these 16 episodes, we classified 9 cases as osteomalacia and 7 as other diagnoses. Thus, the prevalence of biochemical osteomalacia was 0.02% (9/42,171) for 25OHD measurements and 0.23% (8/3432) for 25OHD<25nmol/L. All cases of osteomalacia with 25OHD measurements prior to supplementation had 25OHD≤18nmol/L. The prevalence of biochemical osteomalacia is very low, even in individuals with 25OHD<25nmol/L.

Calcium Citrate Versus Calcium Carbonate in the Management of Chronic Hypoparathyroidism: A Randomized, Double-Blind, Crossover Clinical Trial.

ABSTRACTIn hypoparathyroidism (HypoPT), calcium supplementation is virtually always required, although the disease is likely to be associated with an increased risk of nephrolithiasis. The use of calcium citrate (Ca‐Cit) theoretically could have a positive impact on the nephrolithiasis risk because citrate salts are used to reduce this risk. Our objective was to evaluate the potential therapeutic advantage of Ca‐Cit in comparison with calcium carbonate (CaCO3) in HypoPT, on nephrolithiasis risk factors, as well as to their ability to maintain desirable serum calcium levels. We also evaluated these preparations on quality of life (QOL). This randomized, double‐blind, crossover trial recruited 24 adults with postsurgical chronic hypoparathyroidism at Campus Bio‐Medico University of Rome. Participants were randomized 1:1 to Ca‐Cit or CaCO3 for 1 month and then crossed over to the other treatment for another month. The primary outcomes were changes in albumin‐adjusted serum calcium and in ion activity product of calcium oxalate levels (AP[CaOx] index). Secondary efficacy outcomes included changes in SF‐36 survey score, fatigue score, constipation, and adverse events. No difference in terms of AP(CaOx) index was observed between the two groups. However, Ca‐Cit was associated with a significant reduction in the oxalate/creatinine ratio compared with CaCO3 (−2.46 mmol/mol [SD 11.93] versus 7.42 mmol/mol [SD 17.63], p = 0.029). Serum calcium and phosphorus concentration was not different between the two calcium preparations. Ca‐Cit was associated with less constipation (p = 0.047). No difference was found in QOL scores. Although Ca‐Cit did not modify the AP(CaOx) index when compared with CaCO3, it was associated with a reduction in urinary oxalate excretion that could have a potential beneficial effect on nephrolithiasis risk. These results are likely to have clinical implications in HypoPT, particularly those who do not tolerate CaCO3 and those affected by nephrolithiasis. A longer‐term experience is needed to confirm these findings. © 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).

Reference interval for albumin-adjusted calcium based on a large UK population.

Primary hyperparathyroidism is a common condition and results in hypercalcaemia, especially in older women. Thus, it is critical to obtain a robust estimate for the upper limit of the reference interval for albumin-adjusted serum calcium in the general population. The current reference interval in use in the UK (Pathology Harmony range, 2.20 to 2.60mmol/L) was based on a consensus. To establish a reference interval for albumin-adjusted serum calcium in men and women. Cross-sectional study of men and women who did not have chronic kidney disease or vitamin D deficiency; outliers were identified statistically and then rejected and then a 99% reference interval was calculated. 502524 men and women aged 40 to 69years from the UK Biobank Study. Serum total calcium, albumin, 25-hydroxyvitamin D, estimated glomerular function (eGFR). We developed an equation for albumin-adjusted serum calcium and applied it to 178377 men and women who did not have chronic kidney disease or vitamin D deficiency. We identified 2962 (1.7%) as outliers, and when excluded, we report a 99% reference interval of 2.19 to 2.56mmol/L (8.76 to 10.24mg/dL). We found that for older (55-69years) and younger women (40-55years) the upper limits were 2.59mmol/L and 2.57mmol/L and that for all men, the upper limit was 2.55mmol/L. We have established an upper limit of the reference range for older women that would identify all high outliers (2.60mmol/L and above). The upper limit for young women and for men is lower, at 2.57 and 2.55mmol/L respectively. The current reference interval in use has to be updated and improved based on these findings. These upper limits may prove helpful for identifying hypercalcaemic disorders like primary hyperparathyroidism in clinical practice.

Denosumab-associated hypocalcemia: Does gender play a role?

ObjectiveIt is well recognized that the presentation, treatment, and outcomes of various diseases may differ between men and women. We recently reported a 7.4% rate of denosumab-associated hypocalcemia in community-dwelling osteoporotic patients. This study sought to investigate the role of gender in this complication. Study designRetrospective community-dwelling cohort. MethodThe databases of a large health maintenance organization were searched for adult patients treated with denosumab for osteoporosis in 2010-2018. Rates and predictors of denosumab-associated hypocalcemia (serum calcium ≤8.5 mg/mL) were analyzed by gender. ResultsThe cohort included 1871 women and 134 men. Compared with the women, the men were characterized by older median age (81 vs. 77 years, p = 0.005), higher likelihood to receive denosumab as a first-line treatment (22% vs. 6%, p < 0.001), less treatment with calcium supplements (42% vs. 53%, p = 0.012), and lower median eGFR level (66.1 vs. 79.8 mL/min/1.73m2, p < 0.001). Denosumab-associated hypocalcemia developed in 133 women (7.1%) and 16 men (11.9%) (p = 0.04); the drug was discontinued in 75% and 61%, respectively. The strongest predictors of hypocalcemia in women were levels of pretreatment albumin-adjusted serum calcium (OR 0.08, 95% CI (0.04, 0.14)) and creatinine (OR 2.43, 95% CI (1.45, 4.05)). There were no predictors in men. On propensity matching of 126 men and 126 women, gender was not a predictor of hypocalcemia. ConclusionDenosumab-treated men were significantly older than treated women and had a lower eGFR and more advanced osteoporosis. These findings suggest that selection bias rather than male genderper se underlies the higher rate of denosumab-associated hypocalcemia in men.

Denosumab-induced hypocalcemia in patients with osteoporosis: can you know who will get low?

RCTs have reported a 0.05-1.7% rate of hypocalcemia in denosumab-treated postmenopausal women with osteoporosis, but long-term real-life data are lacking. We assessed the rate of hypocalcemia in osteoporotic community-dwelling patients treated with denosumab. A retrospective analysis was conducted based on medical records (2010-2018) from a large HMO. An albumin-adjusted serum calcium concentration lower than 8.5mg/dL was defined as hypocalcemia. We included 2005 patients (93% women, mean age 76 ± 9years). Hypocalcemia developed during treatment in 149 patients (7.4%; 1% less than 8mg/dL): in 66 after 0.5-1years; 48 after 1-2years; 35 after > 2years. On comparison of the hypocalcemic and normocalcemic patients, the strongest predictors of hypocalcemia were pretreatment levels of albumin-adjusted serum calcium (9.1 ± 0.4 vs. 9.4 ± 0.5mg/dL, respectively; p < 0.05) and creatinine (0.9 ± 0.5 vs. 0.8 ± 0.3mg/dL, respectively; p < 0.05). The hypocalcemia rate increased in parallel to a decrease in eGFR (p = 0.032 for the difference between eGFR ranges). Baseline calcium level ≤ 9.31mg/dL predicted hypocalcemia with a sensitivity of 77% and specificity of 56%. A model of (- 2)*calcium + creatinine predicted hypocalcemia (3.7% when lower and 17.1% when higher than - 17.4). Gender, age, 25-hydroxyvitamin-D, parathyroid hormone, alkaline phosphatase, and whether denosumab was given as first or advanced line of osteoporotic therapy had no predictive value. Real-life rates of denosumab-induced hypocalcemia are higher than previously reported. Hypocalcemia might develop after each dose of denosumab in ongoing treatment. Adequate calcium and vitamin D supplementation are needed. Serum calcium monitoring is advised in high-risk patients for early detection of severe hypocalcemia.

Abaloparatide in patients with mild or moderate renal impairment: results from the ACTIVE phase 3 trial

Objective: To evaluate, post hoc, the efficacy and safety of abaloparatide by degree of renal impairment.Methods: ACTIVE was a phase 3, 18-month, randomized, double-blind, active-comparator, placebo-controlled study of postmenopausal women with osteoporosis who received subcutaneous abaloparatide 80 µg, placebo, or open-label teriparatide 20 µg daily. Patients with serum creatinine >2.0 mg/dL or 1.5–2.0 mg/dL with an estimated glomerular filtration rate (eGFR) <37 mL/min, calculated by Cockcroft-Gault formula, were excluded.Results: At baseline, 660 patients had eGFR ≥90 mL/min, 1276 had 60 to ˂90 mL/min, and 527 had <60 mL/min. Older age and lower T-scores were associated with greater renal impairment. Among renal-function subgroups, there were no meaningful changes in bone mineral density, fracture risk reduction, or overall incidence of treatment-emergent adverse events in the active-treatment arms. Anemia, nausea, hypercalcemia, and upper-respiratory-tract infection tended to be more frequent with increasing renal impairment. Hypercalcemia measured by albumin-adjusted serum calcium occurred significantly less frequently with abaloparatide than teriparatide in patients with eGFR <60 mL/min (3.6% versus 10.9%; p = .008) and in the overall ACTIVE safety population (3.4% versus 6.4%; p = .006). Computed tomography scans in 376 patients revealed no evidence of increased renal calcification.Conclusion: Increased exposure to abaloparatide and teriparatide in patients with renal impairment led to no meaningful differences in efficacy or safety. These results support the use of abaloparatide without dosage adjustment in patients with renal impairment, provided those with severe renal impairments are monitored for adverse events.