Novel Non-Invasive Methods for the Diagnosis or Renal Osteodystrophy in Dialysis Patients.

Renal osteodystrophy (ROD) is a metabolic bone disease, affecting virtually all patients with end-stage renal failure. Compared to the general population, the incidence of hip fractures is 4-fold increased in dialysis patients. Pathophysiologic abnormalities found in ROD are complex. Perturbations of bone turnover (T), mineralization (M), and volume (V) can be found. So far, only invasive bone biopsies with subsequent histomorphometry allow for correct TMV classi-fication of ROD. Currently available non-invasive methods such as dual-energy X-ray absorptiometry (DXA) or measurement of serologic parameters such as parathyroid hormone or markers of bone turnover show modest sensitivity/specificity for the correct classification of ROD. Several new modalities for the non-invasive diagnosis of ROD are being studied. Among radiological methods, high-resolution peripheral quantitative computed tomography (HR-pQCT) is a promising new technique. HR-pQCT has been shown to be superior to conventional DXA for the discrimination of dialysis patients with and without a history of low-impact fracture. Among new serological markers, measurement of sclerostin seems worth studying. Serum sclerostin levels showed a high positive predictive value for the diagnosis of high-turnover bone disease in a cohort of dialysis patients who had undergone bone biopsies. Despite promising new approaches, more research is still needed. Specifically, there is currently no method which has been shown to predict the occurrence of fractures in dialysis patients.