Study of Trabecular Bone Score (TBS) as a Fracture Risk Factor in Chronic Renal Failure

Observational study

The Trabecular Bone Score (TBS) is a recent imaging tool that indirectly studies bone microarchitecture from 2-dimensional images of lumbar biphotonic absorptiometry (DXA). His interest is demonstrated in the evaluation of the fracture risk of the general population. The study of its interest in chronic renal failure is ongoing, only 3 studies have been published to our knowledge.

Osteopathy of chronic renal failure is a complex phenomenon involving bone remodeling disorders, mineralization, mass and bone microarchitecture. In the renal transplant population, certain factors, such as anti-rejection therapy, are also involved.

The impact of fragility fractures induced by these disorders of bone metabolism is a major public health issue due to the resulting morbidity and mortality, with mortality doubling in comparison to the general population after a hip fracture.

The bone osteopathy assessment of chronic renal failure is the bone biopsy, however its realization is very limited because of its invasiveness.

Although initially Bone Densitometry was not recommended in the evaluation of the fracture risk of chronic renal failure by KDIGO (Kidney Disease Improvement Global Outcomes) of 2009, many works published since plead in favor of its realization for the fracture risk assessment, in combination with the clinical data of the Fracture Risk Assessment Tool (FRAX), as should be recommended in the next KDIGO. Indeed, the decrease in bone density in chronic renal failure is associated with an increased risk of fracture.

Clinical parameters, of course, also play an important role in the evaluation of the fracture risk of chronic renal insufficiency, be it the items taken into account in FRAX, certain factors related to chronic kidney disease, or even transplantation. kidney transplant.

To our knowledge, only three studies on the association of TBS with fracture risk of chronic renal failure have been published. In particular, they show a significant association between the decrease in TBS and the incident fracture risk, independently of bone density and FRAX, in a population of kidney transplant recipients, and chronic renal insufficiency in stage 3 or 4.

According to KDIGO 2009, the only biomarkers recommended in the evaluation of osteopathy chronic renal failure are parathyroid hormone (PTH) and bone-specific alkaline phosphatase (BAP), although there is no established threshold for significant increase in fracture risk . However, there is little data on other bone remodeling markers such as the Procollagen type 1 N-terminal propeptide (P1NP) and the C-terminal telopeptide of type 1 collagen (CTX). Some studies indicate, however, that they may be of interest in evaluation of osteopathy of chronic renal failure .

Eligibility Criteria:
Inclusion Criteria:

* 1st population: kidney failure patients at stage 4-5, age\> 40 years, non-dialyzed, ungrafted.
* 2nd population: kidney transplant patients, age\> 40, first kidney transplant.

Exclusion Criteria:

* Pregnant women.
* Incapable adults (tutelage, guardianship, safeguard of justice).
* Persons deprived of liberty.