LAUSR

The revised Kidney Disease Improving Global Outcomes (KDIGO) guidelines for Chronic Kidney Disease Mineral and Bone Disorder (CKD-MBD) will soon be published. Perhaps the most important insight arising from the concept of CKD-MBD that was developed in 2005, followed by the CKD-MBD guidelines in 2009, is that the kidneys, bone and vasculature do not act separately, but as an interactive coregulatory system mediating mineral homeostasis; and that with advancing kidney disease, abnormalities of this integrated system compromise cardiovascular and musculoskeletal health. The past decade has seen progress in understanding the complex pathogenesis of CKD-MBD, including previously unrecognized interactions with the brain, autonomic nervous system, the microbiome and many metabolic pathways. While the updated KDIGO guidelines will reflect advances in this understanding, the guidelines rely on evidence; and the availability of an adequate evidence base for treatments of CKD-MBD remains an unmet need. There is currently a dearth of well designed and executed randomized, double blind, placebo-controlled trials, demonstrating the effectiveness of interventions to influence morbidity and mortality or to improve quality of life of patients with CKD-MBD. This is a formidable challenge and reflects the difficulty of designing studies for patients with heterogeneous kidney diseases and accompanying bone disease. Compounding this difficulty, many investigations used in the diagnosis and management of CKD lack sensitivity and/or specificity, or only detect late disease. This lack of high level evidence imposed a conservative approach to management in the 2009 KDIGO CKD-MBD guidelines, and the revised guidelineswill necessarily have similar short comings that will frustrate the expectations of some clinicians. With these limitations in mind, a ‘CKD-MBD Controversies and Directions’ workshop was convened in September 2015, involving renal physicians, endocrinologists, skeletal physiologists and imaging specialists from the Australian and New Zealand Society of Nephrology (ANZSN) and Australian and New Zealand Bone and Mineral Society (ANZBMS) to bring the challenges we face into sharper focus. Areas for discussion included current and emerging treatment targets for CKD-MBD, an assessment of current and proposed laboratory investigations and imaging modalities, and an exploration of ways to improve management and direct research. This supplement contains the proceedings of that meeting, updated by authors to the end of 2016, and is intended to identify unmet needs in the field of bone and mineral metabolism. Some comments are provided in the succeeding text.