Characterization of vitamin D metabolism in active acromegaly in the setting of bolus (150,000 IU) cholecalciferol treatment

Elevated Vitamin D leading to an Incidental Diagnosis of Multiple Myeloma

A case involving the incidental diagnosis of multiple myeloma (MM) due to interference in the 25-hydroxy-vitamin D (25(OH) vitamin D) immunoassay is presented. The patient, under the care of rheumatology and receiving treatment with alendronic acid and vitamin D supplements, was referred to endocrinology for investigation of acromegaly. Acromegaly was subsequently ruled out; however, during the investigations, consistently elevated levels of 25(OH) vitamin D were noted, raising suspicion of vitamin D resistance syndrome. The laboratory and endocrinology teams engaged in discussions, and following the cessation of medication, repeated analyses for 25(OH) vitamin D and a single analysis of 1,25-dihydroxy-vitamin D levels were requested, yielding high and normal results, respectively. The laboratory conducted a three-step interference investigation, ultimately identifying a high molecular weight molecule responsible for the initially elevated 25(OH) vitamin D levels. Due to the clinical presentation of back pain, a proteinogram was requested, revealing a monoclonal band of 36 g/L. Subsequent free light chain analysis indicated an elevated ratio. With three risk factors identified, this was classified as an established MM and urgently referred to haematology for correct management. Laboratory assay interferences have the potential to disrupt the accurate diagnostic workup of patients. Collaborative discussions between laboratory and clinical teams regarding such cases aid in directing the diagnostic pathway appropriately, facilitating prompt and proper diagnosis and management.

Vitamin D in pituitary driven osteopathies

The evidence that pituitary hormones may bypass peripheral endocrine glands to exert remarkable effects on the skeleton is gaining ground. Both hormonal excess and deficit may determine impairment in bone structure, and they commonly result in bone loss in patients affected by pituitary and neuroendocrine disorders. Vertebral fractures are the most common skeletal alterations and may occur independently of bone mass. Use of vitamin D (VD) supplementation is still debated in this setting. This review will focus on the interactions between different metabolites of VD and pituitary hormones, and the effects of VD supplementation on bone metabolism in patients with pituitary diseases.

Novel approach to bone comorbidity in resistant acromegaly

Active acromegaly may lead to irreversible complications. Among them, acromegaly osteopathy and fragility (vertebral and hip) fractures have emerged as frequent and precocious events in the natural history of the disease, being correlated with longer disease duration and higher growth hormone (GH) levels, accounting for patients' reported poor quality of life, physical performance and other life-impacting complications. Differently from primary osteoporosis, bone mineral density is not a reliable tool to predict fracture risk in this clinical setting, as patients with active disease frequently have normal or slightly reduced bone mass; whereas bone quality is particularly compromised, as determined by low trabecular bone score (TBS) in patients with active disease as compared to healthy controls or patients with cured/controlled disease. The evidence of impaired bone microstructure has been profoundly investigated with different computed tomography (CT) techniques, reporting low trabecular number and thickness as well as wide but more porous cortical bone, providing an explanation for such a high prevalence of vertebral fractures (up to 40-50% in selected cohorts). Since data on bone-active drugs are scanty, disease control remains a cornerstone to prevent fractures. Nonetheless, some potential protective effects may derive from vitamin D supplementation and pasireotide therapies, independently from disease status. Aim of this manuscript is to review the current and emerging evidence on skeletal fragility in patients with active and resistant acromegaly.

New insights into the vitamin D/PTH axis in endocrine-driven metabolic bone diseases

BACKGROUND

Endocrine regulation of bone metabolisms is the focus of the "Skeletal Endocrinology" series of meetings.

AIMS

To report on the outcome of the discussion on the role of vitamin D/PTH axis in endocrine osteopathies held during the 10th Skeletal Endocrinology Meeting which took place in Stresa (Italy) in March 2023.

OUTCOMES

Vitamin D/PTH axis has relevant influence on several outcomes in the general population and in patients affected by endocrinopathies such as hypoparathyroidism and secreting pituitary adenomas.

CONCLUSIONS

Assessing the status of the vitamin D/PTH axis and using vitamin D and PTH as therapeutic agents is mandatory in several endocrine-related bone metabolic conditions.

Cholecalciferol Use Is Associated With a Decreased Risk of Incident Morphometric Vertebral Fractures in Acromegaly

CONTEXT

Skeletal fragility is observed in 30% to 60% of acromegaly patients, representing an emerging complication of the disease that increases disability. Despite several studies having investigated the clinical and hormonal prognostic factors for the occurrence of vertebral fractures (VFs) in acromegaly, very few data are available on their prevention/treatment including the effect of vitamin D (VD) supplementation, which has been reported to have a fracture-protective effect in several studies in patients with osteoporosis.

OBJECTIVE

We aimed to investigate the role of cholecalciferol (D3) supplementation in the prevention of incident VFs (i-VFs) in acromegaly.

METHODS

A longitudinal, retrospective and multicenter study was performed on 61 acromegaly patients treated and untreated with D3 supplementation.

RESULTS

Twenty-six patients were treated with D3 supplementation according to clinical guidelines. The median D3 weekly dosage was 8500 IU (interquartile range [IQR]: 3900). The median duration of D3 supplementation was 94 months (IQR: 38). At last follow-up, i-VFs were diagnosed in 14 patients (23%). I-VFs were less prevalent in patients on D3 supplementation (14.3% of cases) compared to patients not treated with D3 (85.7%; P = .02). The final level of serum V25OH-D was significantly lower in patients who developed i-VFs (28.6 ng/mL, IQR: 4.1) compared to patients who did not develop i-VFs (34.2 ng/mL, IQR: 9.6; P = .05). The logistic regression confirmed the protective role of D3 supplementation on the occurrence of i-VFs (odds ratio: 0.16; 95% CI, 0.03-0.79; P = .01).

CONCLUSION

It is likely that D3 supplementation could lead to a reduction in i-VFs in acromegaly.

Serum Phosphorus and Calcium as Biomarkers of Disease Status in Acromegaly

Acromegaly is a chronic disease caused by the hypersecretion of growth hormone (GH), leading to changes in the growth of visceral tissues and glucose impairment. Serum biomarkers that correlate with disease status are still unclear. This study aims to assess the potential of phosphorus and calcium as biomarkers in the clinical evaluation of patients with acromegaly and clarify their relationship with SAGIT and other common biomarkers. We retrospectively analyzed data from 306 medical records of patients with acromegaly hospitalized between 2015 and 2020. Factors such as patient biometrics, duration of disease, SAGIT score, tumor size, GH, insulin-like growth factor 1 (IGF-1), calcium, phosphorus, parathormone, and vitamin D were analyzed concerning current disease status (naïve, non-remission, remission). The results showed that serum phosphorus significantly correlated with IGF-1 and SAGIT scores for patients with active acromegaly. Specifically, the best predictor for the remission of acromegaly was a phosphorus level < 3.98 mg/dL and serum calcium levels < 9.88 mg/dL. Based on logistic regression, the higher the serum phosphorus level, the lower the odds of achieving remission (an increase in one unit leads to a decrease in the chance of about 80%). In conclusion, phosphorus and calcium can be effective biochemical markers for predicting disease status in acromegaly.

New tools for bone health assessment in secreting pituitary adenomas

Pituitary hormones regulate skeletal physiology, and excess levels affect bone remodeling and alter bone microstructure. Vertebral fractures (VFs) are an early phenomenon of impaired bone health in secreting pituitary adenomas. However, they are not accurately predicted by areal bone mineral density (BMD). Emerging data demonstrate that a morphometric approach is essential for evaluating bone health in this clinical setting and is considered to be the gold standard method in acromegaly. Several novel tools have been proposed as alternative or additional methods for the prediction of fractures, particularly in pituitary-driven osteopathies. This review highlights the novel potential biomarkers and diagnostic methods for bone fragility, including their pathophysiological, clinical, radiological, and therapeutic implications in acromegaly, prolactinomas, and Cushing's disease.