[Multiple Vertebral Fractures after Denosumab Discontinuation: How to Avoid Them?]

Adjacent vertebral Hounsfield unit value of acute osteoporotic vertebral fracture is a risk factor for concomitant domino osteoporotic vertebral fractures

BACKGROUND

Most patients with acute osteoporotic vertebral fracture (AOVF) are successfully treated conservatively. However, the optimal management method and prognosis for multiple AOVFs are unclear. This study aimed to investigate the prevalence of multiple AOVFs and identify the associated risk factors.

METHODS

This study enrolled 134 hospitalized patients (mean age 83 ± 7.6 years, 66% women) with AOVF treated conservatively between 2017 and 2020. The fractures were diagnosed by magnetic resonance imaging (MRI). The AOVFs were divided into two groups; single osteoporotic vertebral fractures (OVF) and domino OVFs (at least two OVFs). The adjacent vertebral Hounsfield unit values (HU) of the OVF and dual x-ray absorptiometry (DXA) of the lumbar spine or hip were used to evaluate the bone mineral density (BMD). Logistic regression analysis was performed to identify the risk factors for domino OVFs.

RESULTS

Domino OVFs were noted in 21 (15.7%) of 134 patients. There were 10 cases of adjacent level and 11 cases of remote level. The BMI (18.5 ± 4.2 vs. 21.2 ± 4.6, p = 0.025) and adjacent vertebral HU value of OVF (57.3 ± 17.5 vs. 76.6 ± 24.1, p = 0.008) were significantly lower in the domino OVFs group than in the single OVF group. Logistic regression analysis revealed the adjacent vertebral HU value of the OVF as an independent risk factor for domino OVFs, (odds ratios (OR) 0.96, p = 0.012). The domino OVF group had a significantly higher decline in gait ability (76% vs. 48%, p = 0.017).

CONCLUSIONS

The adjacent vertebral HU value of AOVF is a useful tool for evaluating BMD for domino OVFs. The optimal treatment for osteoporosis should be considered to prevent subsequent domino OVFs.

Stopping Denosumab

PURPOSE OF REVIEW

Denosumab discontinuation is associated with a rebound effect manifesting by an increased risk of multiple spontaneous vertebral fractures. The purpose of this review is to (1) better characterize this risk and (2) find solutions to avoid it.

RECENT FINDINGS

In the absence of a potent bisphosphonate prescription at denosumab discontinuation, the frequency of multiple vertebral fractures is common or frequent (≥ 1/100 and < 1/10). In five recent case series, the median number of vertebral fractures was 5 within 7 to 20 months (median 11) after the last denosumab injection. Prescribing bisphosphonate before starting denosumab and/or after stopping denosumab may reduce this risk. However, only small case series have evaluated these strategies. After the second denosumab dose, there is a rebound effect with an increased risk of multiple vertebral fractures. A potent bisphosphonate prescribed at denosumab discontinuation could reduce this risk. As denosumab discontinuation is characterized by many uncertainties, denosumab is a second-line treatment for osteoporosis. Studies are urgently needed to define the management of denosumab discontinuation.