Kidney Week

Abstract: SA-PO656

The Relationship Between Density Measurements and Histomorphometric Parameters of Cortical Bone of Patients in the Early Stages of CKD

Session Information

• Bone and Mineral Metabolism: Clinical - II
  October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Bone and Mineral Metabolism

• 402 Bone and Mineral Metabolism: Clinical

Authors

• Bittencourt, Amandha, Federal University of Sao Paulo, Sao Paulo, Brazil

Amandha Bittencourt,

• Canziani, Maria Eugenia F., Federal University of Sao Paulo, Sao Paulo, Brazil

Maria Eugenia F. Canziani,

• Rodrigues, Larissa, Federal University of Sao Paulo, Sao Paulo, Brazil

Larissa Rodrigues,

• Rochitte, Carlos Eduardo, Heart Institute (InCor) University of São Paulo Medical School , São Paulo, Brazil

Carlos Eduardo Rochitte,

• Carvalho, Aluizio B., Federal University of Sao Paulo, Sao Paulo, Brazil

Aluizio B. Carvalho,

Background

Cortical bone comprises a compact tissue, which is denser, less porous and metabolically active than trabecular bone. These differences give to the cortical bone a mechanical function while the mineral homeostasis is the main role of the trabecular bone. In order to evaluate these tissues, bone biopsy is the gold standard tool, but it is an invasive and expensive method. In this context, the possibility of using a non-invasive technique is clinically relevant. Quantitative computed tomography of the vertebrae (QCT) is effective for evaluating trabecular bone when compared to structural histomorphometric parameters of patients with chronic kidney disease (CKD). This relationship has not yet been fully evaluated in cortical bone. We investigated the relationship between vertebrae density measured by QCT and structural histomorphometric parameters of cortical bone of patients in the early stages of chronic kidney disease.

Methods

A post-hoc analysis of a cross-sectional study with 50 CKD stage 2-5ND patients undergone QCT and bone biopsy. Undecalcified bone samples from iliac crest was submitted to histomorphometric analysis using the Osteomeasure software (Osteometrics Inc., Atlanta, GA, USA). The histomorphometric parameters analyzed were: Ct.Po (cortical porosity) and Ct.Th (cortical thickness). The cortical bone density, expressed in Hounsfield Units (HU), was obtained by QCT from the thoracic vertebrae at the aorta root.

Results

Patients were 52+10years, 68%male and 30%diabetes mellitus. Laboratorial data included eGFR34±16 mL/min/1.73m², ionized calcium 1.30±0.06mmol/L, phosphorus 3.8±0.7mg/dL, alkaline phosphatase 116(71.5;160.5)U/L; iPTH 83(53.5;167.5)pg/mL, 25OHD30.8±10.1ng/dL and 1,25OH₂D 35.8(30;47.5)pg/mL. Regarding cortical histomorphometric parameters, cortical porosity was 4.6%(2.6;6.6) and cortical thickness was 578.4+151.8μm. The cortical bone density was 379.0 HU(344.7;411.4). There was no correlation between cortical porosity and cortical density(p=0.67) or cortical thickness and cortical density(p=0.41).

Conclusion

Cortical bone density measured by quantitative computed tomography is not associated to structural histomorphometric parameters of cortical bone of patients in the early stages of chronic kidney disease.

Funding

• Government Support - Non-U.S.