Quantitative histomorphometric analysis of halved iliac crest bone biopsies yield comparable ROD diagnosis as full 7.5mm wide samples.

BACKGROUND AND OBJECTIVES: Histomorphometric analysis of a transiliac bone biopsy is the gold standard for the diagnosis of renal osteodystrophy (ROD). This procedure is costly, invasive and usually performed with a trephine with an internal diameter of 7.5 mm. Our objective was to evaluate the accuracy of ROD diagnosis on halved histological bone sections to determine if they are comparable to the standard 7.5 mm samples. DESIGN: We included 68 bone biopsies performed in CKD patients for diagnostic purposes with a 7.5 mm diameter trephine. Quantitative histomorphometric analysis of the whole bone samples was performed including assessment of bone mineralization, turnover and volume. Each histological section (representing the whole 7.5 mm diameter biopsy) was then divided lengthwise in two hemisections (representing the 3.5 mm diameter biopsy). Histomorphometric analysis was repeated this time on the two hemibiopsies for each sample, blinded from initial results. Diagnoses were classified as osteitis fibrosa, adynamic bone disease, mixed uremic bone disease, osteomalacia or other. Correlations between the whole sample and the hemibiopsies for each parameter were studied. Concordance between the various bone parameters and final ROD diagnosis obtained from the whole section versus the two hemi sections was evaluated. RESULTS: Highly significant correlations were found between parameters measured on the whole section and the corresponding hemisections, with r coefficient of 0.98 for osteoid surface and thickness and bone formation rate, 0.97 for osteoclast surface, and 0.96 for bone volume (p < 0.001). Final diagnosis was in full accordance between the whole biopsy and the two corresponding hemi-biopsies in 91% of cases. CONCLUSIONS: Accurate diagnosis of ROD type was obtained by evaluation of bone surface areas of 3 mm diameter. These data suggest that small invasive bone biopsies might provide accurate ROD diagnostics while decreasing both invasiveness and cost of the procedure.

Sclerostin within the chronic kidney disease spectrum.

Sclerostin is sometimes presented as a promising biomarker in assessing bone health both in the general population and chronic kidney disease patients. However, it is still unclear whether it has any true added value compared to existing bone biomarkers in predicting bone turnover and/or bone density in chronic kidney disease patients. A wealth of papers has been published to evaluate the association between sclerostin and vascular calcifications development or even as prognostic biomarker for mortality, but often with conflicting results. Standardization and harmonization of analytical techniques is a prerequisite to advance clinical knowledge in sclerostin.