[Fractures and chronic renal insufficiency]

Chronic renal insufficiency (CRI) causes important modifications in the metabolism of phosphorus and calcium, to which frequently resulting in serious disorders of the skeleton, including demineralization, reduction of the bone resistance and a higher risk of fractures. Renal osteodystrophy is the term used to describe these disorders; they are generally heterogeneous and are classified according to the state of bone turnover into secondary hyperparathyroidism, adynamic bone, and osteomalacia. The incidence of hip fractures in the patients with CRI is higher than in the general population. Hip fractures are an important cause of morbidity and mortality. The evaluation of the fracture risk in the patients with different degrees of CRI is problematic, in particular because of the difficulty in identifying fractures, especially vertebral ones. The instrumental index that best expresses the fracture risk in the general population is bone mineral density (BMD); however, the relationship between low BMD and CRI is disputed. Bone disorders in patients with CRI have in fact a multifactorial pathogenesis and low BMD is not the only risk factor for fractures. Besides densitometric evaluation, also that vertebral morphometric evaluation would be desirable in patients with CRI. The fracture risk increases progressively with the severity of chronic renal disease and it is especially high in patients with renal insufficiency in more advanced-stages CRI (creatinine clearance<15-20 mL/min). However, not only in patients with severe CRI undergoing dialysis, but also in those with milder renal disease is the risk of bone fractures high.