Osteoporosis is defined simply seeing that “a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture. intervention in systemic mineral metabolism also enhances bone strength today. Thus the use of drugs that directly take action on bone and the introduction of fracture liaison concept are promising strategies for fragility fracture prevention among CKD patients as well as treatment for CKD-MBD. Keywords: Fragility fracture Osteoporosis Chronic kidney disease-related bone and mineral disease (CKD-MBD) Fracture liaison Introduction Various pathological conditions are found in bone among patients with chronic kidney disease (CKD) and the pathophysiological mechanisms that underlie these lesions are also complicated. Here I briefly review the present condition of fragility bone BGJ398 fracture and its treatment in CKD patients. Osteoporosis and CKD-MBD Osteoporosis is usually defined by the World Health Business as “a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture” . This definition omits the following which had been included in the previous definition ; “low bone mass” and “microarchitectural deterioration of bone tissue”. The revision clearly indicates that this latter conditions are no longer a requirement or a sufficient condition of osteoporosis. In other words any bone condition that causes fragility fracture is now considered as osteoporosis. However the disease definition is frequently misunderstood because bone mass measurement is still the standard method to diagnose osteoporosis. Although osteoporosis is usually a disease characterized by compromised bone strength there is no practical tool to monitor bone mechanical strength at bedside today. Bone mass is indeed a strong determinant of bone mechanical strength ; bone mass is used as a diagnosing BGJ398 tool for osteoporosis under the premise that extremely low bone mass could be regarded as a sufficient condition of compromised bone strength. Since low bone mass is usually neither a requirement nor a sufficient condition of compromised bone strength a current diagnosis of osteoporosis is quite inaccurate which could lead to both false-negative and false-positive cases. Yet we do not have any other practical tools that show bone strength with the exception of a patient’s medical history. Thus bone mass measurement is considered the most powerful tool available today to diagnose osteoporosis. However bone mass is not the only determining factor of bone mechanical strength. Factors other than bone mass that determine bone mechanical strength are generally considered aspects of “bone quality” . It has often been said that “bone mechanical strength is usually predominantly prescribed by bone mass and bone quality contributes” which seems to be true in most of the cases but not all the cases. For example bone mineral density is generally low in elementally school children and although they fall quite often they seldom suffer from fragility fractures. Thus bone quality is sometimes likely to be a more important factor than bone mass for preventing fragility fracture at least in some patient populations. At present BGJ398 the ratio of importance of bone mass and bone quality is not obvious. A primary reason for this is RGS8 that it is hard to define bone BGJ398 mechanical strength. Because the risk of fragility fracture incidence is also dependent on the risk of fall it does not strictly represent bone mechanical strength. In ex lover vivo destruction studies using extracted bone samples different results will be obtained based on the direction or instant of force applied to the samples. Moreover bone hardness and viscoelastic properties are different characteristics that contribute independently to the resistance against destruction . Thus BGJ398 osteoporosis is usually a heterogeneous disease condition in that many factors contribute to bone fragility with different proportions in each case. The disease background is also quite heterogeneous. Chronic kidney disease-related bone and mineral disease (CKD-MBD) is usually defined by the Kidney Disease: Improving Global Outcomes as “a systemic disorder of mineral and bone metabolism due to CKD which is usually.