Risk factors of the poor long-term prognosis of osteoporotic vertebral fractures: A multicenter cohort study

The presence of existing osteoporotic vertebral fracture (OVF) increases the mortality risk. However, the influence of the characteristics of OVF is unclear. This study aimed to investigate the influence of new OVF on patients’ long-term prognosis using our past cohort study.Method: This is an extension study of our cohort study carried out between 2005 and 2007. In the present extension study, of 420 patients, 197 whose contact information was available at the 6-month follow-up were included in the telephone survey in 2018. Five patients refused to participate in the survey, and 82 could not be contacted. Eventually, 110 patients were enrolled. Of the Demographic data, radiological findings, medical history, and clinical outcome were investigated at injury onset and at the 6-month follow-up. A proportional hazard model was used to investigate the risk factors for mortality.Results: Among 110 patients, 33 died. Male sex and low body mass index (BMI <18.5 kg/m 2 ) were significant risk factors for mortality [hazard ratio (HR) = 6.40, 1.01–40.50; 5.24, 1.44–19.04, respectively]. The history of stroke and liver disease increased the risk of mortality (HR = 13.37, 1.93–92.7; 6.62, 1.15–38.14, respectively). As regards radiological findings, local kyphosis progression per 1° or ≥7° were significant risk factors of mortality (HR = 1.20, 1.06–1.36; 5.38, 1.81–16.03, respectively).Conclusions: A telephone survey at 12 years after the occurrence of OVF analyzed risk factors for mortality and showed that a progression of local kyphosis in fractures between injury onset and 6 months after injury was a risk factor of poor prognosis.