What is the significance of elevated Parathyroid Hormone (PTH) levels in a patient with osteoporosis who has suffered a fracture?

From the Guidelines

The patient likely has primary hyperparathyroidism causing secondary osteoporosis and fracture, and parathyroidectomy should be considered as the definitive treatment, especially with evidence of end-organ damage (fracture). The significance of elevated Parathyroid Hormone (PTH) levels in a patient with osteoporosis who has suffered a fracture is that it indicates an increased risk of further fractures and bone disease. According to the studies 1, elevated PTH levels can lead to excessive bone resorption, reduced bone mineral density, and increased fracture risk.

Medical Management

Medical management should include:

• Bisphosphonates such as alendronate 70mg weekly or zoledronic acid 5mg IV annually to reduce fracture risk
• Calcium intake should be maintained at 1000-1200mg daily without supplementation unless dietary intake is inadequate
• Vitamin D levels should be normalized to 30-50ng/mL with supplementation of 1000-2000 IU daily if deficient
• Cinacalcet (30-90mg daily) may be used to lower PTH levels if surgery is contraindicated

Fracture Management

The fracture should be managed appropriately with orthopedic consultation. Primary hyperparathyroidism causes excessive bone resorption as elevated PTH stimulates osteoclast activity, leading to calcium release from bone, reduced bone mineral density, and increased fracture risk. Addressing the underlying hyperparathyroidism while simultaneously treating the osteoporosis is essential for preventing future fractures and improving bone health.

Key Considerations

Key considerations in the management of this patient include:

• The need for careful monitoring of serum levels of calcium, phosphorus, and intact PTH
• The potential for adynamic bone disease with oversuppression of PTH
• The importance of bone biopsy in certain situations to guide therapy and exclude aluminum toxicity
• The need for large studies to evaluate fracture rates and the relationship between vitamin D treatment and bone histomorphometry.

From the FDA Drug Label

TERIPARATIDE injection, for subcutaneous use ... WARNINGS AND PRECAUTIONS Hypercalcemia and Cutaneous Calcification: Avoid in patients known to have an underlying hypercalcemic disorder. ... INDICATIONS AND USAGE Teriparatide injection is a parathyroid hormone analog, (PTH 1-34), indicated for: Treatment of postmenopausal women with osteoporosis at high risk for fracture or patients who have failed or are intolerant to other available osteoporosis therapy (1)

The significance of elevated Parathyroid Hormone (PTH) levels in a patient with osteoporosis who has suffered a fracture is not directly addressed in the provided drug label. However, it can be inferred that elevated PTH levels may be associated with hypercalcemia, which is a contraindication for the use of teriparatide injection in patients with underlying hypercalcemic disorders. 2

From the Research

Significance of Elevated Parathyroid Hormone (PTH) Levels

Elevated Parathyroid Hormone (PTH) levels in a patient with osteoporosis who has suffered a fracture can have both positive and negative effects on bone health.

• Intermittent administration of PTH has been shown to stimulate bone formation, increase bone mineral density, and reduce fracture risk 3, 4, 5.
• PTH therapy can be used to promote fracture healing and restore bone loss in patients with osteoporosis 4.
• However, chronic continuous excess of PTH can lead to increased bone resorption, as seen in primary hyperparathyroidism, resulting in reduced bone mineral density and increased fracture risk 6.

Treatment of Osteoporosis with PTH

PTH is used as an anabolic treatment for osteoporosis, stimulating bone formation and increasing bone mineral density 3, 4, 5.

• PTH therapy has been shown to be effective in reducing vertebral and nonvertebral fractures in patients with osteoporosis 5.
• The choice of PTH receptor agonist, such as teriparatide or abaloparatide, depends on individual patient factors, including fracture risk and medical history 7.

Comparison with Other Osteoanabolic Agents

PTH receptor agonists have been compared to other osteoanabolic agents, such as romosozumab, in terms of their effectiveness in reducing fracture risk and increasing bone mineral density 7.

• PTH receptor agonists have been shown to increase bone formation and bone mineral density, while romosozumab stimulates bone formation and reduces bone resorption 7.
• The choice between PTH receptor agonists and romosozumab depends on individual patient factors, including medical history and convenience of administration 7.