Serum vitamin D and parathyroid hormone profiles in patients with various stages of renal disease

Vitamin D in Saudi Arabia: Prevalence,distribution and disease associations

More than 33 years have passed since the first paper highlighting vitamin D deficiency as a public health concern in Saudi Arabia was published in 1983. Despite "early" detection,it wasn't until the year 2010 where the interest in vitamin D research grew exponentially worldwide and was finally visible in Saudi clinical and academic areas. Since then,many landmark studies have been generated with regards to the physiologic functions of vitamin D,both skeletal and extra-skeletal. This review is limited to the prevalence,distribution A systematic review on the prevalence studies done in KSA from 2011 to 2016 was done and revealed that the prevalence of vitamin D deficiency (<50nmol/l) in Saudi Arabia among different populations (adults,children and adolescents,newborns and pregnant/lactating women) is 81.0% (Confidence Interval 95% 68.0-90.0),in line with most neighboring Gulf countries. Vitamin D deficiency in KSA has been mostly associated with bone and insulin-resistant diseases but limited data are available to prove causality. In conclusion,there is a need to develop local consensus guidelines that will identify candidates for screening,monitoring and treating those who are at most risk for vitamin D deficiency complications.

Assessment of bone turnover markers to predict mineral and bone disorder in men with pre-dialysis non-diabetic chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is commonly associated with disturbances in mineral metabolism and bone disease. Bone biopsy is the gold standard in diagnosing mineral bone disorder. Hence the search for non-invasive assessment of bone health gains importance. We undertook to assess the bone health in men with stage 4 and 5 chronic kidney Disease.

METHODS

We recruited 32 male subjects with Stage 4 and 5 chronic kidney disease and 32 age-matched healthy male controls. 25-hydroxyvitamin D, intact parathyroid hormone, and bone-specific alkaline phosphatase were assayed. Bone mineral density (BMD) was estimated using dual-energy X-ray absorptiometry.

RESULTS

CKD is associated with significantly higher levels of bone-specific alkaline phosphatase and intact parathyroid hormone and lower levels of 25-hydroxyvitamin D and bone mineral density, when compared to controls. In the multivariate linear regression model, bone-specific alkaline phosphatase emerged as an independent predictor of reduced BMD. Receiver Operator Characteristic analysis for prediction of reduced BMD in CKD showed both intact parathyroid hormone and bone-specific alkaline phosphatase have significant predicting power.

CONCLUSION

The combination of bone-specific alkaline phosphatase and intact parathyroid hormone has more significant predicting power and is a more reliable index for non-invasive assessment of bone health in men with chronic kidney disease, than either marker when used alone.

Plasma calcidiol, calcitriol, and parathyroid hormone and risk of new onset heart failure in a population-based cohort study

Background

Heart failure (HF) is a major problem in the Western world, with increasing prevalence and incidence. Because HF cannot be cured, prevention of HF is of utter importance. Calcidiol, calcitriol, and parathyroid hormone (PTH) have been identified as risk factors for cardiovascular disease. However, their association with new onset HF remains to be established. We investigated whether calcidiol, calcitriol, and PTH could be used to identify those subjects at risk for new onset HF, and if they had additive predictive value over established risk predictors like N‐terminal‐pro Brain‐type natriuretic peptide and highly sensitive Troponin‐T.

Methods and results

We examined 7470 HF‐free participants in Prevention of Renal and Vascular End‐stage Disease, a community‐based cohort study in Groningen, the Netherlands (latitude 53°N, mean age: 49 years, 48% male). During follow‐up time of 12.6 years (interquartile range: 12.3–12.9), 281 participants (4%) developed HF: 181 (66%) HF with reduced and 94 (34%) HF with preserved ejection fraction (HFrEF [left ventricular ejection fraction ≤ 40%], and HFpEF [left ventricular ejection fraction ≥ 50%], respectively). Mean (±SD) of calcidiol was 58 (±24) nmol/L, mean calcitriol 145 (±48) pmol/L, and median (interquartile range) PTH was 3.7 (3.0–4.6) pmol/L. Calcidiol levels were univariately associated with new onset HF [hazard ratio (HR) 0.82 (95% CI 0.69–0.96)], but calcitriol levels were not [HR 0.85 (95% CI 0.71–1.03)]. PTH levels kept their predictive value after adjustment for age, sex, and day of blood withdrawal (HR 1.26 [95% CI 1.04–1.53]). However, in our full model this association was lost [HR 1.10 (95% CI 0.92–1.32)]. Calcidiol, calcitriol, and PTH could not differentiate between new onset HFrEF or HFpEF.

Conclusions

After adjustment for confounding factors, a single measurement of plasma calcidiol, calcitriol, or PTH was not associated with risk of developing HF. Screening for these markers to identify subjects at risk for new onset HF cannot be advocated.

Expanding the net: The re-evaluation of the multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) in the setting of secondary hyperparathyroidism and the development of the MultIdimensional Predictive hyperparaTHyroid model (Mi-PTH)

BACKGROUND

The multidimensional nomogram calculating the upper limit of normal PTH (maxPTH) model identifies a personalized upper limit of normal parathyroid hormone (PTH) and successfully predicts classical primary hyperparathyroidism (PHP). We aimed to assess whether maxPTH can distinguish normocalcemic PHP (NCPHP) from secondary hyperparathyroidism (SHP), including subjects who underwent bariatric surgery (BrS).

METHODS

A total of 172 subjects with 359 complete datasets of serum calcium (Ca), 25-OH vitamin D, and intact PTH from Oregon were analyzed: 123 subjects (212 datasets) with PHP and 47 (143) with SHP, including 28 (100) with previous BrS. An improved prediction model, MultIdimensional evaluation for Primary hyperparaTHyroidism (Mi-PTH), was created with the same variables as maxPTH by the use of a combined cohort (995 subjects) including participants from previous studies.

RESULTS

In the Oregon cohort, maxPTH's sensitivity was 100% for classical PHP and 89% for NCPHP, but only 50% for normohormonal PHP (NHPHP) and 40% specific for SHP. In comparison, although sensitivity for NCPHP was similar (89%), Mi-PTH vastly improved SHP specificity (85%). In the combined cohort, Mi-PTH had better sensitivity of 98.5% (vs 95%) and specificity 97% (vs 85%).

CONCLUSION

MaxPTH was sensitive in detecting PHP; however, there was low specificity for SHP, especially in patients who underwent BrS. The creation of Mi-PTH provided improved performance measures but requires further prospective evaluation.