Updates in CKD-Associated Osteoporosis

Abstract

Purpose of review: Chronic kidney disease (CKD) is associated with bone loss and fractures. The purpose of this review is to provide clinicians with an overview of the underlying pathogenesis of CKD-associated osteoporosis, and a summary of the current diagnostic and therapeutic approaches to this disease.

Recent findings: In 2017, the Kidney Disease Improving Global Outcomes Committee on Bone Quality updated their guidelines to include screening for osteoporosis and fracture risk by dual energy X-ray absorptiometry in patients with CKD. Once a diagnosis of osteoporosis and/or fracture risk is established, it is not clear how nephrologists should manage their patients. Patients with CKD should be screened for CKD-associated osteoporosis and considered for strategies that prevent bone loss and fractures. Assessment of bone turnover via imaging, biochemical testing, or bone biopsy can help guide the choice of therapy. Randomized controlled trials are needed to assess safety and efficacy of treatments to prevent bone loss and fractures.

Keywords: CKD-MBD; Osteoporosis; Renal osteodystrophy.

Figure 1.. The Elements of Bone Strength

Bone strength is defined by bone quality and bone quantity. Bone quality pertains to bone material properties and includes bone turnover, microarchitecture, microdamange and collagen properties. Bone quantity pertains to the bone mineral density of trabecular and cortical bone.

Figure 2.. Non-Invasive Diagnosis of ROD

Non-invasive skeletal imaging can be used to assess the presence of skeletal abnor-malities and to classify fracture risk. Measurement of bone mineral density can be done by dual energy X-ray absorptiometry (DXA). Microarchitecture and mineral density of trabecular and cortical bone can be assessed by quantitative computerized tomography (QCT) and by high-resolution peripheral computerized tomography (HR-pQCT). Alternatively, assessment of turnover type can also be based on bone turnover markers. Bone formation markers, which are markers of osteoblast function, include bone specific alkaline phosphatase (BALP), osteocalcin, and procollagen type-1 N-terminal propeptide (P1NP). Bone resorption markers, which are markers of osteoclast number and function, include tartrate-resistant acid phosphatase 5b (Trap-5b) and C-terminal telopeptides of type I collagen (CTX).