From the Guidelines
The patient's elevated parathyroid hormone (PTH) of 117.8 pg/mL and low vitamin D level of 25 ng/mL indicate secondary hyperparathyroidism due to vitamin D deficiency, and I recommend starting vitamin D supplementation with ergocalciferol (vitamin D2) 50,000 IU once weekly for 8 weeks, followed by maintenance therapy with cholecalciferol (vitamin D3) 1,000-2,000 IU daily, as suggested by the NCCN task force report 1.
The goal of this treatment is to achieve a vitamin D level above 30 ng/mL, which should normalize the PTH level. This approach addresses the underlying vitamin D deficiency that is causing the parathyroid glands to overproduce PTH in an attempt to maintain normal calcium levels. In elderly patients like this 69-year-old female, vitamin D deficiency is common due to reduced sun exposure, decreased dietary intake, and diminished ability of the skin to synthesize vitamin D. Correcting the vitamin D deficiency will allow calcium absorption to improve, which should subsequently normalize the PTH level.
Some key points to consider in this treatment plan include:
- Ensuring adequate calcium intake of 1,000-1,200 mg daily through diet or supplements, as recommended by the NCCN task force report 1
- Rechecking both vitamin D and PTH levels after completing the 8-week loading dose to assess response to treatment
- Monitoring for potential side effects of vitamin D supplementation, such as hypercalcemia and hyperphosphatemia, as noted in the K/DOQI clinical practice guidelines 1
Overall, the treatment plan should prioritize normalizing the patient's vitamin D level and PTH level, while also ensuring adequate calcium intake and monitoring for potential side effects. By following this approach, we can improve the patient's bone health and reduce the risk of complications associated with secondary hyperparathyroidism.
From the Research
Vitamin D Deficiency and PTH Levels
- A 69-year-old female with a vitamin D level of 25 and a PTH level of 117.8 may be experiencing vitamin D deficiency, which can have negative consequences on musculoskeletal and extra-skeletal health 2.
- Studies have shown that vitamin D supplementation can help achieve optimal serum levels of 25(OH)D, which is essential for maximum benefit at the lowest risk 2, 3.
Treatment Options
- Cholecalciferol is considered the form of vitamin D of choice for exogenous supplementation, as it guarantees an exact dosage in IU and has pharmacokinetic properties that allow for flexible administration 2, 4.
- Ergocalciferol, on the other hand, is less stable and less potent per microgram dose than cholecalciferol, but may still be effective in raising serum 25(OH)D levels 3, 5.
- A study comparing cholecalciferol and ergocalciferol found that cholecalciferol was more effective at raising serum 25(OH)D levels in non-dialysis-dependent CKD patients while active therapy was ongoing 5.
PTH Level Response
- A decrease in PTH levels is associated with an increase in 25(OH)D levels, and a multivariate logistic regression model showed that an increase in 25(OH)D level greater than 5 ng/mL is associated with a significant likelihood of a greater than 30% decrease in plasma intact PTH level 6.
- However, another study found no significant difference between cholecalciferol and ergocalciferol in terms of changes in serum PTH or 1,25(OH)2D levels 5.
Supplementation Regimens
- Different supplementation regimens, including daily or weekly administration of cholecalciferol or ergocalciferol, have been shown to be effective in achieving and maintaining optimal 25(OH)D levels 3.
- A study found that 50,000 IU of ergocalciferol twice weekly provided the most rapid attainment and highest mean levels of vitamin D 3.