Endocrine Abstracts

Introduction: Chronic hypoparathyroidism is a rare disease, which usually treated with active forms of vitamin D and oral calcium. 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 in patients with chronic hypoparathyroidism depending on different 25(OH) vitamin D (25(OH)D) values.

Methods: 40 patients with chronic hypoparathyroidism (38 with postsurgical and 2 with idiopathic) 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)D in the total group (1–with 25(OH)D <35.0 ng/ml; 2 - with 25(ОН)D ≥35.0 ng/ml). To assess the variability of calcium during the day, the measurement of the total calcium (Ca_total) was carried out every 2 hours within 24 hours, albumin - once in the early morning (to calculate albumin-adjusted calcium, Caadj). All patients received conventional treatment with active metabolites/analogues of vitamin D (alfacalcidol, calcitriol) and calcium supplements.

Results: Serum 25(OH)D level was significantly higher in group 2 (28.45 ng/ml vs 44.15 ng/ml, P<0.001, U-test). There were no significant differences between groups by Ca_total, Ca_adj levels and daily calciuria. Patients with serum 25(ОН)D level ≥ 35.0 ng/ml had significant tendency to achieve more often the target levels of Ca_total (128 vs 149 measurements during the day, P=0.049, χ²). However, this tendency disappeared for Ca_adj (P=0.517, χ²). The frequency of hypercalcemia by Ca_adj was significantly lower in patients with 25(ОН)D ≥35.0 ng/ml (P=0.006, χ²), but not for Ca_total (a trend, P=0.042, χ²). As regards hypocalcemia, there were no significant differences by Ca_adj (P=0.581, χ²) and it tends to lower frequency by Ca_total (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. In this study, we did not confirm statistically significant differences for chronic hypoparathyroidism in the calcium profile depending on different 25(OH)D levels. But we obtained some promising statistical further studies are required.