This finding was reported in “Alternate-day calcium dosing may be an effective treatment option for chronic hypoparathyroidism,” a study published in the Journal of Endocrinological Investigation.
Conventional treatment of chronic hypoparathyroidism currently consists of daily oral calcium supplements and active vitamin D analogs — compounds with a similar structure to that of vitamin D. Treatment goals include maintaining blood calcium and phosphate levels in the normal range, and reducing disease symptoms, which can range from tingling or numbness in the fingers, toes or around the lips (paresthesias) to severe muscle cramps and muscle spasms.
However, in some patients, treatment is not effective despite these high doses of calcium supplements.
Recent therapeutic approaches such as recombinant human parathyroid hormone (rhPTH) enabled less intake of calcium supplements and active vitamin D analogs — although such treatments presented challenges due to their under-the-skin administration and high cost.
Based on such approaches, a Turkish team hypothesized that oral calcium administration every other day would have a better absorption than daily supplements. As such, they tested this approach in patients with uncontrolled chronic hypoparathyroidism, who were followed on a regular basis between January 2017 and January 2019.
The alternate-day regimen was given to 14 women with uncontrolled hypothyroidism after receiving at least 2,000 mg per day of oral calcium (a high dose). These women had visited the emergency department within the three months prior to the study, and had been given intravenous calcium replacement.
The scientists analyzed the patients’ medical history, as well as blood and urinary parameters over a three-month period before and after switching to alternate-day treatment with calcium.
The results showed that, compared with pre-switch levels, treatment every other day was associated with reduced calcium intake (1500 mg/day vs. 3750 mg/day) and increased blood calcium levels (8.25 mg/dL vs. 7.71 mg/dL).
Among other parameters, 24-hour urinary calcium excretion increased with the every other day regimen (210.5 mg/day vs. 165 mg/day), though this difference was not statistically significant.
In addition, changing to alternate-day calcium led to a substantial drop in visits to the emergency department, from an average of 21 with the prior regimen to only two after the switch.
Two patients no longer needed treatment with rhPTH, and three left the parathyroid transplant waiting list upon their own request.
“At this point, we believe that ADR [alternate-day regimen] could be a new and cost-effective treatment option that might significantly reduce CHP [chronic hypoparathyroidism] patients’ need for second-line therapy,” the researchers said.
The investigators noted that their study was limited by its small patient size. Further research is needed to make a “firm recommendation,” they said. However, they said the findings were encouraging.