Intra- and interobserver variability of Kleerekoper's method in vertebral fracture assessment

Radiographically detected vertebral fractures (VF) are a hallmark of osteoporosis. Several approaches to describe VF have been proposed. The objective of this study was to evaluate the intra- and interobserver variability of semiquantitative Kleerekoper's method in osteoporotic VF assessment. Sixty-seven postmenopausal osteoporotic (L2-4 T-score < or =-2.5) women with a mean age of 65.2+/-7.51 years were included into the study. Lateral radiographs of thoracic and lumbar spine were evaluated in all patients. Kleerekoper's method was used to define VF. Two observers evaluated all radiographs independently. To investigate intraobserver reproducibility, the first observer reevaluated all radiographs a month later on a separate occasion. Intra- and interobserver agreement was calculated using the kappa statistic. The agreement between two readings for the first observer was 86.3% with a corresponding kappa score of 0.573 (95% confidence limits of kappa score were 0.505-0.642). Interobserver agreement was 87.7% with a corresponding kappa score of 0.660 (95% confidence limits were 0.602-0.718). We observed a moderate agreement for Kleerekoper's method in vertebral fracture assessment. There is no gold standard or standardized measurement or description for VF. Quantitative assessment of VF is essential in epidemiologic studies and in clinical drug trials, but a semiquantitative technique, which is done by experienced observers, should also be added to evaluate the entire spectrum of visible features that are helpful in identifying deformities.