Radiological Factors Associated with Bisphosphonate Treatment Failure and Their Impact on Fracture Healing in Postmenopausal Women with Osteoporotic Vertebral Fractures

Abstract

(1) Background: Bisphosphonate treatment failure is one of the most difficult clinical problems for patients with osteoporosis. This study aimed to analyze the incidence of bisphosphonate treatment failure, associated radiological factors, and effect of fracture healing in postmenopausal women with osteoporotic vertebral fractures (OVFs). (2) Methods: A total of 300 postmenopausal patients with OVFs who were prescribed bisphosphonate were retrospectively analyzed and divided into two groups according to the treatment response: response (n = 116) and non-response (n = 184) groups. The radiological factors and the morphological patterns of OVFs were included in this study. (3) Results: The initial BMD values of the spine and femur in the non-response group were significantly lower than those in the response group (all Ps < 0.001). The initial BMD value of the spine (odd ratio = 1.962) and the fracture risk assessment tool (FRAX) hip (odd ratio = 1.32) showed statistical significance in logistic regression analysis, respectively (all Ps < 0.001). (4) Conclusions: The bisphosphonate non-responder group showed a greater decrease in BMD over time than the responder group. The initial BMD value of the spine and the FRAX hip could be considered radiological factors influencing bisphosphonate non-response in the postmenopausal patients with OVFs. The failure of bisphosphonate treatment for osteoporosis has a possible negative on the fracture healing process in OVFs.

Keywords: bisphosphonate; bisphosphonate treatment failure; bone mineral density; fracture healing; osteoporosis; osteoporotic vertebral fracture.

Figure 1

A flowchart of this study.

Figure 2

A 60-year-old woman who was diagnosed with an osteoporotic vertebral fracture (OVF) at T12. (a) To investigate morphological parameters, the kyphotic angle (KA), Cobb angle, anterior vertical height (AVH), middle vertical height (MVH), and posterior vertebral height (PVH) along with the AVH, MVH, and PVH of the adjacent upper and lower levels (AVH’ and AVH’’, MVH’ and MVH’’, PVH’ and PVH’’) were measured on lateral radiographs. From these parameters, the vertebral body compression ratio (VBCR), the percentage of anterior height compression ratio (PAHC), and the percentage of middle height compression ratio (PMHC) were calculated. (b) Sagittal magnetic resonance imaging showed an endplate type of T12 OVF with the presence of an intravertebral cleft sign (yellow arrow). (c) After two-years of follow-up with zoledronic acid medication, the VBCR, PAHC, and PMHC in lateral radiographs were also measured for the assessment of morphological factors.

Figure 3

Incidence rate of bisphosphonate treatment failure in postmenopausal patients with osteoporotic vertebral fractures.

Figure 4

Receiver-operating characteristic (ROC) curve analysis for the initial BMD of the spine and initial FRAX hip. (a) ROC analysis revealed a cut-off value of −2.75 for the initial BMD of the spine as a good predictor (p < 0.001; area under the curve (AUC) = 0.730; sensitivity = 71.6%, specificity = 69.3%). (b) ROC analysis revealed a cut-off value −4.45% for the initial FRAX hip as a good predictor (p < 0.001; AUC = 0.722; sensitivity = 65.8%, specificity = 67.2%).