Two methods Genant semiquantitative (GSQ) technique and a modified algorithm-based qualitative (mABQ) were compared for assessment of osteoporotic vertebral fracture (VF) on lateral spine radiographs. For this 4465 women and 1771 men with ≥50 years age were from the Canadian Multicentre Osteoporosis Study with their X-ray images at baseline were observed. Observer agreement found as lowest for grade 1 VFs after assessment by GSQ. Among physician readers, the agreement was greater for VFs diagnosed by mABQ.

It was also found that GSQ VF prevalence and incidence were higher than with the mABQ method. The incidence was 6.3/1000 person-years. Women showed more prevalent and incident VFs compared to men as defined by mABQ. But this was not cased as defined by GSQ. Prevalent GSQ VFs were predominantly found in the mid-thoracic spine, whereas prevalent mABQ and incident VFs by both methods co-localized to the junction of the thoracic and lumbar spine. Prevalent mABQ VFs compared with GSQ VFs were more highly associated with reduced adjusted L1 to L4 bone mineral density (BMD), femoral neck BMD, and total hip BMD. Prevalent mABQ VFs compared with prevalent GSQ were also highly associated with incident VF by GSQ, incident VF by mABQ, and incident non-vertebral major osteoporotic fractures. Grade 1 mABQ VFs, but not grade 1 GSQ VFs, were associated with incident non-vertebral major osteoporotic fractures.