Predictors of residual low back pain after acute osteoporotic compression fracture

Background: Studies on the clinical and radiographic risk factors for the residual low back pain beyond 6 months after osteoporotic vertebral fractures (OVFs) are lacking. Hence, this study aimed to characterize a patient population with residual low back pain 48 weeks after acute OVFs and to identify the risk factors associated with residual low back pain. Methods: This prospective multicenter study included 166 female patients aged 65–85 years with acute one-level OVFs. We defined the residual low back pain as visual analog scale (VAS) for low back pain ≥3.5 at 48 weeks in this study, as VAS score ≥3.5 is used to describe moderate or severe pain. Thus, outcome and risk factor analyses were performed by comparing patients with VAS scores <3.5 and ≥ 3.5. In the radiographic analysis, the anterior vertebral body compression percentage was measured at 0, 12, and 48 weeks. Magnetic resonance imaging (MRI) was performed at enrollment and 48 weeks. Results: Of the 166 patients analyzed, 58 complained of residual low back pain at 48 weeks after OVFs. At 0 weeks, the VAS score was significantly higher, and the JOABPEQ mental health score and anterior vertebral body compression percentage were significantly lower in patients with persistent pain 48 weeks after OVFs. The independent risk factors in the acute phase for persistent pain 48 weeks after OVFs were a high VAS score, MRI T2 fluid-intensity image pattern, and a lower anterior vertebral body compression percentage. Conclusions: Severe low back pain, MRI T2 fluid-intensity image pattern, and severe vertebral body collapse in the acute phase were significant risk factors for residual low back pain 48 weeks after OVFs. Patients with acute OVFs who have these risk factors should be carefully monitored for the possible development of residual chronic low back pain.