During the initial management of acute osteoporotic spinal fracture, different types of anti-osteoporosis medication may result in different clinical and radiologic outcomes, according to study results published in Osteoporosis International.
While anti-osteoporosis medications can increase bone mineral density, they may also cause excessive suppression of physiologic bone remodeling, leading to the development of atypical femoral fractures and osteonecrosis of the jaw. Previous studies have suggested impaired healing after osteoporotic spinal fracture with the use of antiresorptive medications. However, there are no studies that assess the effect of parathyroid hormone in these cases.
The study goal was to investigate the radiologic and clinical results after the use of different medications, including antiresorptive and anabolic agents, in patients with acute osteoporotic spinal fracture.
The study cohort included 132 patients who were allocated to 3 groups: group 1 (39 patients; mean age, 71.6±8.1 years) did not receive any anti-osteoporosis medication, group 2 (66 patients; mean age, 70.0±8.2 years) received bisphosphanates, and group 3 (27 patients; mean age, 75.7±10.1 years) received daily anabolic parathyroid hormone and teriparatide, dependent on the use of anti-osteoporosis medication during the 3 months after diagnosis of spinal fracture.
Radiographic parameters including height and local kyphosis of the index vertebrae, magnetic resonance image classification, bone mineral density, and the presence of intravertebral cleft were recorded by two researchers to assess impaired healing. Clinical parameters included pain (numerical rating scale) and disability due to back pain (Oswestry Disability Index).
There was no significant difference in pain score or kyphotic angle at the last follow-up between the groups. The Oswestry Disability Index was higher in group 3 (36.4±16.6) compared with group 1 (28.9±8.8) and group 2 (26.4±6.2) at the last follow-up (P =.009); however, overall changes in disability score were similar in all 3 groups. The degree of improvement in the numerical pain rating scale was better in group 3 (5.7±2.1) compared with group 1 (3.1±2.2) and group 2 (3.5±1.7; P <.001).
There were 30 cases with evidence of intravertebral cleft sign. Rate of intravertebral cleft sign was lower in group 3 (7.4%) compared with group 1 (20.5%) and group 2 (30.3%), but the difference was not statistically significant (P =.053).
Midportion type fracture was defined as cortical disruption of the vertebral body at the midportion on a plain radiograph with magnetic resonance signal changes around the midportion of the vertebrae. Magnetic resonance classification of fracture as midportion type was associated with a higher risk for an increase in kyphotic angle and increased height loss.
Treatment with parathyroid hormone was associated with reduced risk for increased height loss (odds ratio, 0.325; 95% CI, 0.094-1.130; P =.029). In addition, parathyroid hormone usage was associated with a significantly lower incidence of the occurrence of intravertebral cleft (odds ratio, 0.160; 95% CI, 0.029-0.877; P =.035).
The researchers acknowledged that the study had several limitations, including its retrospective nature, relatively few cohorts, and heterogeneity that may have introduced selection bias.
“These findings suggest that proper selection of medication could improve initial management of acute [osteoporotic spinal fractures],” concluded the researchers.
Min HK, Ahn JH, Ha KY, et al. Effects of anti-osteoporosis medications on radiological and clinical results after acute osteoporotic spinal fractures: a retrospective analysis of prospectively designed study [published online August 17, 2019]. Osteoporos Int. doi:10.1007/s00198-019-05125-0