Assessment of arterial stiffness and plasma FGF23 levels in patients with hypoparathyroidism.

INTRODUCTION

Patients with hypoparathyroidism are at a higher cardiovascular risk (CVR) due to mechanisms that are not yet well understood. In patients with renal failure, fibroblast growth factor 23 (FGF23) has been associated with an increased calcification and arterial stiffness (AS), leading to an increased CVR. In hypoparathyroidism-due to the situation of hyperphosphatemia-an increase in FGF23 is also probable. There is a paucity of research examining the relationship between FGF23 levels and AS in patients with hypoparathyroidism. The present study aims to assess AS, by measuring aortic pulse wave velocity (aPWV), and FGF23 levels in patients with hypoparathyroidism vs age and sex matched healthy controls.

MATERIAL AND

METHODS

We conducted a cross-sectional descriptive study, and collected demographical data of patients and treatment characteristics (calcium and vitamin D doses). Furthermore, we measured aPWV using the SphygmoCorXCEL® device and assessed FGF23 and all other parameters of calcium-phosphorus metabolism in a blood and 24h-urine samples.

RESULTS AND DISCUSSION: A total of 20 subjects with hypoparathyroidism (85% postoperative) and 16 healthy matched controls were included. The mean age was 58.6 years (SD, 12.2). The mean course of the disease was 16.31 years (3-44). Regarding the general characteristics, the most remarkable finding was that patients had an estimated glomerular filtration rate (eGFR) significantly lower than controls (72.5 [SD, 21.25] vs 95.3 [SD, 12.21]ml/min/1.73m2; p<0.001). FGF23 levels were clearly elevated in subjects with hypoparathyroidism (255.2 [35.9-1487.4] vs 61.9 [27.8-134.8]RU/mL; p<0.05). A trend toward higher AS was observed in subjects with hypoparathyroidism (aPWV 8.4 [5.2-17.3] vs 6.9 [5.1-10.8]m/s; p=0.08), as well as a positive correlation between aPWV and time of disease progression (r=0.679; p<0.01). A negative correlation was observed in subjects with hypoparathyroidism between aPWV and eGFR (-0.519; p<0.05). We found no significant correlation between aPWV and FGF23 or with phosphate levels or calcium supplements or calcitriol doses used in replacement treatment.

CONCLUSIONS

In subjects with hypoparathyroidism there is a marked increase in FGF23 levels and a trend toward a higher AS, which correlates with disease duration. However, these findings may be conditioned by an impaired renal function that this pathological process entails. A causal relationship could not be established between the elevated levels of FGF23 and AS.