INTRODUCTION:
Low bone mineral density, history of vertebral fractures, and steroids are risk factors for vertebral fractures. Age, nutritional status, muscle mass, and spinal sagittal alignment have also been reported to contribute to risks of osteoporosis and fractures. In this study, we investigated risk factors for the occurrence of new vertebral fractures, including nutritional status, muscle mass, and spinal alignment.
METHODS:
The participants were 597 patients with osteoporosis (94 men and 503 women; mean age 70.5 years) who visited our outpatient department and were available for follow-up 1 year after the visit. We obtained the following data: age at examination, presence of secondary osteoporosis, lumbar spine bone mineral density, number of vertebral fractures, grip strength (better left or right was used), trunk muscle mass (corrected by the square of height), Controlling Nutritional Status (CONUT) score (a measure of nutritional status), sagittal vertical axis (SVA; a measure of spinal sagittal alignment) on all spine standing X-rays, and the treatment status of osteoporosis at baseline. The group with new vertebral fractures confirmed on complete spine X-ray at the 1-year follow-up visit was defined as the group with new vertebral fracture occurrence. In addition to comparisons of each item between the two groups, multivariate analysis was performed, using the presence of new vertebral fracture as the objective variable, to investigate independent risk factors for the occurrence of new vertebral fractures.
RESULTS:
In total, 60 (10.1%) new vertebral fractures occurred during the 1-year period. Comparison between the groups with and without new vertebral fracture occurrence showed no significant differences in age, gender, presence of secondary osteoporosis, lumbar spine bone mineral density, number of existing vertebral fractures, grip strength, trunk muscle mass, and osteoporosis medications used (p>0.05); however, the CONUT score and SVA were significantly higher in the group with new fracture occurrence (p<0.05). Stepwise multiple logistic regression analysis identified high CONUT score and SVA as independent risk factors for the occurrence of new vertebral fractures.
DISCUSSION:
Approximately 10% of patients with osteoporosis in our hospital had a new vertebral fracture within a year, and these patients had malnutrition and spinal sagittal malalignment at baseline. We surmised that malnutrition and spinal sagittal malalignment may be independent risk factors for new vertebral fractures, and patients with these factors should be aggressively treated with drugs that have high evidence of reducing the risk of vertebral fractures, such as anabolic steroids.