Bone Mineral Density Monitoring in Contiguous versus Non-Contiguous Lumbar Vertebrae: The Manitoba BMD Registry

Area of Science:

• Osteoporosis research
• Bone densitometry
• Clinical diagnostics

Background:

• Clinically meaningful bone mineral density (BMD) changes on repeat DXA (dual-energy x-ray absorptiometry) must exceed the 95% least significant change (LSC).
• Lumbar spine DXA often omits vertebrae with artifacts, necessitating measurements from non-contiguous vertebrae.
• Previous concerns suggested lower precision with non-contiguous versus contiguous vertebrae.

Purpose of the Study:

• To compare least significant change (LSC) and BMD response to osteoporosis medication between non-contiguous and contiguous lumbar spine vertebrae.
• To evaluate the clinical utility of non-contiguous vertebrae in DXA scans.

Main Methods:

• Calculated LSCs for lumbar spine DXA using 879 scan-pairs from the Manitoba BMD Program.
• Compared BMD changes from contiguous and non-contiguous vertebrae in 11,722 patients with two DXA examinations.
• Analyzed BMD changes in relation to intervening anti-osteoporosis medication use.

Main Results:

• Least significant changes (LSCs) were comparable between contiguous and non-contiguous vertebrae.
• High correlations (Pearson r≥ 0.9) were observed between BMD changes from L1-L4 and all combinations of vertebrae.
• Similar percentage changes in spine BMD and treatment-concordant changes exceeding LSC were found for both contiguous and non-contiguous vertebrae.

Conclusions:

• Lumbar spine BMD changes can be reliably assessed using 2 or 3 non-contiguous vertebrae when necessary.
• Precision using non-contiguous vertebrae is similar to that of contiguous vertebrae.
• Non-contiguous vertebrae effectively detect treatment-concordant BMD changes comparable to contiguous vertebrae.