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Introduction: Approaches for recognizing vertebral fractures remain controversial. Methods: An age-stratified population sample of 512 postmenopausal women was followed with serial radiographs for up to 12 years (4455 person-years). Results: 112 women experienced a new vertebral fracture (20% reduction in any vertebral height from baseline) within this study period, for an annual age-adjusted (to US white women [greater than or equal to] 50 years of age in 2000) incidence of 23 per 1000. Depending on the morphometric definition used, the prevalence of vertebral deformities at baseline ranged from 3 to 90%. A recent method to standardize vertebral heights produced the best agreement with a qualitative clinical reading of the films [kappa ([kappa]), 0.53]. Almost all of the different baseline definitions predicted future vertebral fractures, but most of the predictive power was attributable to the severe (e.g., 4 SD) deformities included within more generous (e.g., 3 SD) classifications. Whereas the generous definitions were more sensitive, and the restrictive ones more specific, their overall abilities to predict a new vertebral fracture were roughly comparable as evaluated by the c-index (analogous to the area under an ROC curve). Conclusion: This result suggests that the choice of a morphometry definition depends on the particular application and, in particular, on whether it is more important to maximize sensitivity or specificity. Keywords Epidemiology * Incidence * Osteoporosis * Prevalence * Vertebral fracture

Byline: G. Jiang (1), R. Eastell (1), N. A. Barrington (2), L. Ferrar (1) Keywords: Osteoporosis; Prevalence; Vertebral fracture Abstract: The identification of vertebral fracture in osteoporosis is based mainly on the identification of abnormal variation in vertebral shape, but this can be misleading in the presence of a non-fracture deformity or normal variant of vertebral shape. Qualitative identification of vertebral fracture (Qual) is influenced by the subjectivity of the approach, and although more objective, the semiquantitative method (SQ) can be difficult to apply. In addition, there has been little independent evaluation of SQ in relation to other approaches. We aimed to evaluate a new algorithm-based approach for the qualitative identification of vertebral fracture (ABQ) and to compare it with SQ and Qual. Two radiologists reported spinal radiographs for 372 postmenopausal women using Qual (reader 1), and SQ and ABQ (reader 2). Non-fracture deformities and normal variants were also reported using Qual and ABQ. The prevalence of vertebral fracture by subjects was higher for SQ (24%) than for Qual (11%) and ABQ (7%). Agreement was poor between SQ and the other methods, and moderate between Qual and ABQ. Twenty-two women with vertebral fracture were agreed by all three methods, similar to the total identified by ABQ (25 women). Seventeen women diagnosed with fracture by Qual, had non-fracture deformity or normal variant (but no fracture) according to ABQ. Of the women with SQ fractures, 53% and 70% were identified negative for fracture but positive for non-fracture deformity or normal variant by ABQ and Qual. The main sources of discrepancy between SQ and the other methods were Scheuermann's disease, normal variation, and degenerative change accompanied by short anterior vertebral height. For all methods, bone mineral density (BMD) and BMD Z-scores were lower in women with vertebral fractures than in those with no fractures. Bone mineral density and BMD Z-scores were also lower at the lumbar spine and total body in women with vertebral fractures according to Qual and ABQ than they were for SQ, and were lower in women with SQ fractures agreed by Qual and ABQ, compared with those diagnosed negative for fracture by Qual and ABQ (p&lt 0.01). We conclude that poor agreement between methods arises mainly from difficulties in differentiating true fracture from non-fracture deformity. Our new approach attempts to address this problem but requires further testing in a larger study population. Author Affiliation: (1) Bone Metabolism Group, Section of Human Metabolism, Division of Clinical Sciences, University of Sheffield, Sheffield, UK (2) Department of Diagnostic Imaging, Northern General Hospital, Sheffield, UK Article History: Registration Date: 09/03/2004 Received Date: 19/08/2003 Accepted Date: 08/03/2004 Online Date: 08/04/2004

Byline: L. Ferrar (1), G. Jiang (1), R. Eastell (1) Keywords: Key words:Absorptiometry -- Deformity -- Osteoporosis -- Radiography -- Vertebra Abstract: Vertebral wedge angle is greater in older men than in women of similar age, and increases with age in men. Wedge angle may depend less on bone size than other methods (for example, height ratios), and thus could be more effective at identifying wedge deformities. We aimed to compare mean wedge angle measured by morphometric X-ray absorptiometry (MXA) in young men and women, to assess the effect of age on wedge angle in women, and to compare wedge angle and anterior--posterior (ha/hp) height ratios for the identification of vertebral deformities. Mean wedge angle was similar in normal men (n= 46) and women (n= 106) ages 22--50 years, and did not change significantly with age in normal women ages 22--83 years (n= 222). MXA reference intervals for ha/hp ratios (trimmed mean minus 3.0 SD) and wedge angle (trimmed mean + 3.0, 2.5 and 2.0 SD) were used to identify vertebral wedge deformities in 83 women with osteoporosis, ages 49-- 87 years. For agreement with semiquantitative assessment of radiographs (SQ), kappa (Io) = 0.76 for wedge angle mean plus 2.0 SD, and 0.74 for ha/hp height ratio mean minus 3.0 SD. Sensitivity was marginally better for wedge angle plus 2.0 SD than for ha/hp when all SQ grades of deformity were included, but there was no difference between methods for detection of moderate to severe deformities (grades 2 to 3). Diagnostic values for the two approaches were broadly similar. The results of this analysis do not provide strong evidence for the preferential use of the wedge angle approach. Author Affiliation: (1) Bone Metabolism Group, Section of Medicine, Division of Clinical Sciences, University of Sheffield, Sheffield, UK, GB Article note: Received: 2 August 2000 / Accepted: 23 May 2001

Byline: L. Ferrar (1), G. Jiang (1), R. Eastell (1) Keywords: Key words:Absorptiometry -- Deformity -- Osteoporosis -- Precision -- Radiography -- Vertebrae Abstract: Morphometric X-ray absorptiometry (MXA) is a low-radiation technique used for the identification of vertebral deformities. The reliability of MXA measurements is dependent on the precision of the technique, and this is influenced by system error, variability associated with morphometric analysis, and variability within study populations. Short-term precision in vivo affects the identification of prevalent deformities, and may vary according to the age and health status of the study population. The aims of this study were to measure short-term precision in vitro and in vivo for MXA, and to compare intraoperator variability for repeat marking of radiographs in morphometric radiography (MRX) and scan images in MXA. For short-term precision in vitro (based on 30 consecutive MXA phantom scans), the coefficient of variation (CV) was approximately 1%. lntraoperator variability for repeat marking of baseline radiographs and MXA scans (marked without the compare facility) in a population-based group of 32 postmenopausal women, was significantly lower for MRX (CV for vertebral heights = 1.5%) than for MXA (CV= 2.9%). The CV for duplicate same-day MXA scans performed in subjects with osteoporosis (n= 20) was 2.2 % for vertebral heights between T8 and L4 using the compare facility, and 4.8% when scans were analyzed without the compare facility. We conclude that short-term precision for MXA is good for vertebrae T8 to L4, but the technique is limited due to poor image resolution in the upper thoracic vertebrae. Intraoperator variability for repeat marking was lower for MRX, but the error associated with marking MXA scans remained below the minimum change required for identification of a vertebral deformity. Author Affiliation: (1) Bone Metabolism Group, Section of Medicine, Division of Clinical Sciences, University of Sheffield, UK, GB Article note: Received: 31 July 2000 / Accepted: 6 February 2001

Byline: L. Ferrar (1), G. Jiang (1), R. Eastell (1) Keywords: Key words: Absorptiometry -- Deformity -- Osteoporosis -- Precision -- Radiography -- Vertebrae Abstract: Morphometric X-ray absorptiometry (MXA) has not been evaluated for the identification of incident vertebral deformities. The reliability of longitudinal measurements in quantitative vertebral morphometry is influenced by the precision of the technique. Long-term precision in vitro (weekly MXA phantom scans) assessed by retrospective cumulative sum (Cusum) analysis, detected one event during a 6-month period when the measurement process was 'out of control'. Inspection of service records revealed that repair work was performed around this timepoint. The coefficient of variation (CV) for long-term precision (vertebral heights) in a population-based sample of postmenopausal women ages 56 to 83, mean 65 +- 6 years (n= 48), was 4.0% for morphometric radiography (MRX), 2.9% for MXA using the compare facility for analysis of serial scans, and 3.2% when 'compare' was not used. In women with osteoporosis ages 49 to 87, mean 67 +- 9 years (n= 50), the CV was 5.0% for MRX, 4.1% for MXA using 'compare' and 8.5% without 'compare'. Precision errors for height ratios (MRX and MXA) were greater than for vertebral heights. Incident deformities were identified by MRX and MXA in the women with osteoporosis, using point prevalence, 20% minimum reduction in vertebral height, and percent least significant change (LSC) in vertebral heights and height ratios. Semiquantitative analysis of radiographs by a radiologist (Genant method) was used as the gold standard. The results were similar for MRX and MXA, and all morphometric criteria identified a similar proportion of true incident deformities, although the false positive rate was generally greater for the height ratio approaches. MXA has good long-term precision and is comparable to MRX for the identification of incident deformities when scans are analyzed with the compare facility. Author Affiliation: (1) Bone Metabolism Group, Section of Medicine, Division of Clinical Sciences, University of Sheffield, UK, GB Article note: Received: 31 July 2000 / Accepted: 6 February 2001