Introduction        The bone mineral density T score threshold for osteoporosis of -2.5 SD lack sensitivity because most fractures occur in persons with osteopenia or normal aBMD, not osteoporosis. Abdominal aortic calcifications may falsely elevate aBMD of lumbar spine in patients with chronic kidney disease, so identifying these individuals is an unmet need that may be addressed by measuring microstructure. High porosity is a consistent observation in animal models of renal disease. The aim of this study was to identify the magnitude of microstructural deteriorations in patients with CKD relative to age-sex matched healthy controls. 

Material and Methods    One hundred and one (49 women and 52 men) subjects with CKD (79 transplants, 22 dialysis) and 178(102 women and 76 men) healthy age matched were recruited. Microstructure of the distal radius was measured and analysed using HR-pQCT. Of 31 women with CKD (mean age 59 yr., 22-75) and 102 sex-age matched controls distal radius images analysed by StrAx algorithm for cortical porosity, matrix mineral density and trabecular compartment indices comparison. 

Results     Compared to controls, women with CKD had 1.3 SD (95%CI 0.86 to 1.62), 1.36 SD (0.94 to 1.76) higher total cortex and compact cortex porosity on distal radius, in addition 1.25SD (0.20 to 0.81), 1.49 SD(0.2 to 1.03) higher porosity on inner and outer transitional zones, respectively. Matrix mineral density was 1.06 SD (-1.46 to0.20) lower. Trabecular vBMD was 1.02 SD lower due to 1.2SD fewer trabeculae and 0.80 SD lower trabecular connectivity (all p<0.01).

Men had 1.1SD (95%CI 0.78 to 1.62) and 1.3SD (1.1 to 1.6) lower total vBMD and trabecular number, respectively and 1.2 SD higher trabecular separation (all p<0.01). 

Conclusions     Microstructure is compromised in patients with CKD.  A major abnormality is increased cortical porosity and reduced matrix mineral density.