Osteoporotic Vertebral Fracture Prevalence Varies Widely Between Radiological Assessment Methods: The Rotterdam Study

Background: Accurate diagnosis of vertebral osteoporotic fractures is crucial for the identification of individuals at high risk of future fractures. Different methods for radiological assessment of vertebral fractures exist, but a gold standard is lacking. The aim of our study was to estimate statistical measures of agreement and prevalence of osteoporotic vertebral fractures in the population-based Rotterdam Study, across the two most commonly applied assessment methods. Methods: The quantitative morphometry (QM) method, evaluates vertebral height loss that affects vertebral shape whereas the algorithm based qualitative (ABQ) method judges endplate integrity and includes guidelines for the differentiation of vertebral fracture and non- fracture deformities. Results: Cross-sectional radiographs were assessed for 7,582 participants aged 45-95 years. With QM, the prevalence was 14.2% (95% CI: 13.4% to 15.0%), compared to 4.0% (95% CI: 3.6% to 4.5%) with ABQ. Inter-method agreement was 0.24 according to kappa statistic and 0.74 according to Prevalence Adjusted Bias Adjusted Kappa (PABAK). The highest agreement between methods was among females (k = 0.31, PABAK= 0.78), participants aged above 80 (k = 0.40; PABAK = 0.66) and at the L1 level (k = 0.40; PABAK= 0.97). With ABQ, most fractures were found at the thoraco-lumbar junction (T12-L1) followed by the T7-T8 level, whereas with QM, most deformities were in the mid (T7-T8) and lower thoracic spine (T11-T12) with similar number of fractures in both peaks. Excluding mild deformities (grade 1 with QM) from the analysis increased the agreement between the methods from k = 0.24 to 0.36 and from PABAK = 0.74 to 0.86, whereas re-examining mild deformities based on endplate depression increased agreement from k = 0.24 to 0.40 and PABAK from 0.74 to 0.86 (p-value< 0.001). Conclusion: Vertebral fracture prevalence differs significantly between QM and ABQ; re-examining QM mild deformities based on endplate depression would increase the agreement between methods. More wide-spread and consistent application of an optimal method may improve clinical care. This article is protected by copyright. All rights reserved