Vitamin D, bone alkaline phosphatase and parathyroid hormone in healthy subjects and haemodialysed patients from West Africa: impact of reference ranges and parathyroid hormone generation assays on the KDIGO guidelines

Abstract

Background The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend targets based on multiples of the upper limit of normal (ULN) of parathyroid hormone (PTH) concentration. However, the ULN has not always been correctly established by manufacturers. While it is known that the ULN is supposed to be higher in African Americans than in Caucasians, it is largely unknown in Africans. Methods We established the ULN of PTH concentration in a population of 240 healthy Ivorians using second- and third-generation PTH assays before and after supplementation with 100 000 IU of cholecalferol. We measured the levels of PTH, bone alkaline phosphatase, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D in 100 haemodialysed Ivorian patients. Results The prevalence of vitamin D deficiency in Ivory Coast is low. The ULN obtained using the third-generation PTH assay was similar to that obtained in Caucasians but was higher when PTH was measured using the second-generation PTH assay. According to the KDIGO guidelines, ∼20% of the haemodialysed patients were below twice the ULN and 30% were above nine times the ULN. Approximately 25% of the patients were even >12 times the ULN. We observed a discrepancy in the results between the two PTH assays (14%) that was relatively more important than what we observed from previous studies in Caucasians using the same strategy. Conclusions We found a low prevalence of vitamin D deficiency in a tropical country like Ivory Coast. We also established the PTH reference range, which could prove useful for the follow-up of haemodialysed patients, particularly for the large number of patients suffering from secondary hyperparathyroidism who are at high risk of adverse bone events.

A review and perspective on the assessment, management and prevention of fragility fractures in patients with osteoporosis and chronic kidney disease

“…The authors found that bALP levels < 33.1 U/L discriminated low from non-low bone turnover and >42.1 U/L high from non-high turnover. Appropriate cut-off values using the Ostase mass bALP (IDS iSYS) have been suggested and include <21 µg/L for discriminating low from non-low bone turnover and >31 µg/L for high from non-high bone turnover [ 43 , 73 ].…”

“…Calcium and vitamin D supplements are often prescribed as adjuncts to osteoporosis treatment. Calcium supplementation is generally considered if dietary calcium is below 700 mg/day, and a calcium intake between 700 and 1200 mg is recommended [ 73 ]. In CKD, extra caution is advised because of impairment in calcium homoeostasis [ 93 ].…”

“…In the general population, vitamin D supplementation alone has minimal effects on fractures and falls unless in severe deficiency, although calcium and vitamin D combined has been shown to have modest anti-fracture efficacy [ 96 ]. In the non-CKD population, although vitamin D (cholecalciferol) supplement of 800 IU daily is advised as maintenance dose in those who are at high risk of fracture risk [ 73 ], it is important that they are also calcium replete to maximise skeletal benefits. A similar recommendation might be made for patients with CKD stages 1–4 due to the positive effects of improved vitamin D status on other outcomes, even in the absence of fracture data.…”

Modulation of cardiometabolic risk and CardioRenal syndrome by oral vitamin D3supplementation in Black and White Southern Sahara residents with chronic kidney disease Stage 3: focus on racial and ethnic disparities

“…Plasma total intact PTH was measured by an electro-chemiluminescence immunoassay run. Based on the KDIGO recommendations [ 32 ]; Hyper-parathyroidism was defined as PTH >65 pg/mL or >6.89 pmol/L. Plasma Aldosterone levels, Plasma Angiotensin II levels and Plasma Renin activity were determined by ELISA assay kit (Isbio, Seattle, WA).…”

Burden, access and disparities in kidney disease: chronic kidney disease hotspots and progress one step at a time

“…Cavalier et al . [7] explore another key issue: to what extent do biochemical thresholds generated in developed countries apply to other populations. They established the upper limit of normal of parathyroid hormone (PTH) concentration in healthy persons from the Ivory Coast and evaluated the prevalence of vitamin D deficiency, which was low.…”