Combined Effects of Vitamin D Status, Renal Function and Age on Serum Parathyroid Hormone Levels

Abstract

BackgroundVitamin D status and renal function are well-known independent predictors of serum parathyroid hormone (PTH) levels. We aimed to describe the combined effects of 25-hydroxy vitamin D (25(OH)D), glomerular filtration rate (GFR) and age on serum PTH levels across the whole clinical spectrum.MethodsWe retrieved from our endocrinology center database all PTH measurement between 2012 and 2020 for which a simultaneous measurement of serum 25(OH)D, calcium and creatinine was available. Age, sex and diagnosis were available for all subjects. Intact PTH was measured using the same electrochemiluminescence assay.ResultsThere were 6,444 adults and 701 children without a diagnosis of hyper- or hypoparathyroidism or abnormal serum calcium levels. In adults with 25(OH)D≥12 ng/mL multiple regression models showed that serum PTH was negatively correlated with both 25(OH)D and GFR. Regression (-0.68 and -1.59 vs. -0.45 and -0.22 respectively), partial correlation (-0.16 and -0.35 vs. -0.12 and -0.10 respectively) and determination coefficients (0.14 vs. 0.031) were higher in CKD than in normal renal function. In subjects with 25(OH)D<12 ng/mL, GFR was the only significant predictor in those with CKD (β-coefficient=-2.5, r=-0.55) and 25(OH)D was the only significant predictor in those with normal renal function (β-coefficient=-2.05, r=-0.11). Increasing age was associated with higher PTH levels only in those with normal renal function and 25(OH)D≥12 ng/mL.ConclusionsWe showed that declining vitamin D and renal function have additive effects on serum PTH in subjects without vitamin D deficiency. In vitamin D deficient subjects this dependency is stronger but is not additive anymore.

Misdiagnosis of chronic kidney disease and parathyroid hormone testing during the past 16 years

“…The pathogenesis of SHPT is complex and driven by many factors, including deficiency of 1,25-dihydroxyvitamin D, hypocalcemia, and hyperphosphatemia 9 , 10 ; CKD is regarded as the primary etiology. The imbalance in the fibroblast growth factor (FGF) –calcium–phosphate–vitamin D–PTH axis translates into vascular calcification and bone dystrophy in patients with stage 3 CKD, resulting in a low estimated glomerular filtration rate (eGFR) 11 , 12 . However, recent studies have shown that low PTH levels (less than twice the upper limit of normal) in patients with end-stage kidney disease are also associated with higher mortality risk 13 , 14 .…”

“…The exploration of CKD-MBD, which is associated with hyperphosphatemia, hypocalcemia, low serum levels of vitamin D, and increased PTH secretion, has gradually increased in recent years 15 . SHPT is one of the most important clinical manifestations of CKD-MBD, and PTH is also a crucial indicator of prognosis in CKD 8 , 11 , 12 . However, there are some indications that clinicians do not seem to pay as much attention to the diagnosis of CKD and the detection of PTH.…”

The role of native vitamin D treatment in the clinical assessment of osteoporosis in patients with chronic kidney disease

“…[38]. The literature shows that severe deficiencies begin to occur in patients with stage 3 CKD, and the deficiency becomes more severe in advanced stages [16,39]. In hemodialysis patients, this deficiency reaches up to 80% [40].…”