Background: Spinal cord injury (SCI) is associated with a marked bone loss short-term after injury and a consequent increased risk of osteoporosis and fractures. We recently observed the development of osteoporosis in nearly 50% of SCI patients one year after injury. Therefore, the aim of this study was to evaluate the factors associated with osteoporosis development in these patients.
Methods: We included patients with complete recent SCI (<6 months) evaluating bone turnover markers (P1NP, bone ALP and sCTx), 25-OH vitamin D levels and lumbar and femoral BMD at baseline, 6 and 12 months after SCI. The risk factors for osteoporosis analysed included: age, gender, BMI, toxic habits, bone turnover markers, 25-OH vitamin D levels, lumbar and femoral BMD, level, severity and type of SCI and days-since-injury. Osteoporosis was defined according to WHO criteria.
Results: 29/42 patients completed the 12-month follow-up. 52% developed osteoporosis during follow-up. Patients who developed osteoporosis had lower BMD values at femur and lumbar spine and higher bone turnover markers values (P1NP and bone ALP) at baseline. On multivariate analysis, the principal factors related to osteoporosis development were: total femur BMD <1 gr/cm2 (RR, 3.61; 95%CI, 1.30-10.06, p=0.002) and lumbar BMD <1.2 gr/cm2 at baseline (0.97 probability of osteoporosis with both parameters under these values). Increased risk for osteoporosis was also associated with increased baseline values of bone ALP (>14ng/mL) (RR, 2.40; 95%CI, 1.10-5.23, p=0.041) and P1NP (>140ng/mL) (RR, 3.08; 95%CI, 1.10-8.57, p=0.017). Conversely, age, BMI, type and time-since-SCI or 25-OHD levels were not related to increased risk of osteoporosis over 12 months.
Conclusions: The evaluation of BMD at the lumbar spine and femur short-term after SCI constitutes the principal factor for predicting the development of osteoporosis during the first year after SCI. These data indicate the need to evaluate and treat these patients shortly after injury.
Disclosure: The authors declared no competing interests. Work funded by a grant from Fundació La Marató de TV3.