Detective value of historical height loss and current height/knee height ratio for prevalent vertebral fracture in Japanese postmenopausal women

Vertebral fracture (VFx) is associated with various co-morbidities and increased mortality. In this paper, we have studied the detective value of height loss for VFx using two indices; historical height loss (HHL) which is the difference between the maximal height, and the current height (CH), and CH/knee height (KH) ratio. One-hundred and fifty-one postmenopausal women visiting the outpatient clinic of orthopaedics were studied for their CH, self-reported maximal height, KH, and radiographically diagnosed VFx number(s). VFx was present in 41.1 % of the subjects. Multiple regression analyses revealed that the number of prevalent fractures was a significant predictor of HHL and CH/KH ratio. Receiver operator characteristic curve analysis has shown that for HHL, the area under the curve (AUC) with their 95 %CI in the parentheses was 0.84 (0.77, 0.90), 0.88 (0.83, 0.94), and 0.91 (0.86, 0.96) for ≥1, ≥2, and ≥3 fractures, respectively. For the presence of ≥1 VFx, the cut-off value was 4.0 cm (specificity 79 %; sensitivity 79 %). Regarding the CH/KH ratio, AUC was 0.73 (0.65, 0.82), 0.85 (0.78, 0.93), and 0.91 (0.86, 0.96) for ≥1, ≥2, and ≥3 fractures, respectively. For the presence of ≥1 VFx, the cut-off value was 3.3 (specificity 47 %; sensitivity 91 %). Both cut-off values for HHL and CH/KH ratio had high negative predictivity across the wide range of theoretical VFx prevalence. Thus, HHL and CH/KH were both good detectors of VFx. Our data would be the basis to determine the cut-off value for the screening or case finding of subjects with VFx.