Vertebral fractures (VF) related to osteoporosis (i.e., severe OP) increase the risk of disability and mortality, but they are often neglected. We observed a severe OP misdiagnosis in 28.9% of inpatients with previous spinal imaging positive for VFs. Diagnosing severe OP is crucial to reduce the health care costs of inpatients. BACKGROUND Vertebral fractures (VFs) related to osteoporosis (OP) increase the risk of additional fractures and death. In inpatients, VFs are often neglected with consequent delay in OP treatments, prolongation of hospitalization, and reduction of life expectancy. The aim of this study was to evaluate the prevalence of a misdiagnosed severe OP (i.e., with VF) in general medicine inpatients. METHODS We evaluated inpatients of a Medicine Unit between January 2019 and December 2019 without severe OP diagnosis, who had spinal imaging. For each patient, we collected demographic data, previous or current OP treatment, and presence/number of VFs. Descriptive data were presented by medians (interquartile range [IQR]) for continuous data or as numbers (percentages) for categorical data. Differences between subgroups were analyzed with chi-square or Kruskal-Wallis tests as appropriate. p-values <0.05 were considered statistically significant. RESULTS 793 subjects were admitted to inpatient's clinic: 235 (135 females and 100 males with a median age of 76.0 [64.0-83.0] years) were enrolled. One or more vertebral fractures were present in 28.9% (68/235) subjects; 47% (32/68) had two or more vertebral fractures. The majority of patients (55/68) with VFs had not previously received a severe OP diagnosis. CONCLUSIONS Severe OP was misdiagnosed in at least 8.6% of inpatients. The prevalence dramatically increases (about 29%) in subjects with previous spinal imaging showing one or more VFs. More attention should be given to this co-morbidity, which is known to be an additional risk factor for disability and mortality.