The association of anticonvulsant use with fractures in spinal cord injury

The aim of this study was to determine whether anticonvulsants, including the benzodiazepine subclass, are associated with an increased risk for lower extremity fractures in male patients with spinal cord injury.

All male patients with a history of a traumatic spinal cord injury of 2 yrs' duration or longer in the Veterans Affairs Spinal Cord Disease Registry from 2002 to 2007 were included. Incident lower extremity fractures during this period and anticonvulsant use were identified. The association of anticonvulsant use, overall, by type (enzyme inducing, non-enzyme inducing), by number (monotherapy vs. polytherapy), by benzodiazepine subclass, and by individual medication used was determined.

In this cohort, 892 veterans sustained a fracture, and 6555 did not. Compared with nonusers of anticonvulsants, there was a significant positive relationship with fractures by overall use of anticonvulsants (HR, 1.17 [95% CI, 1.01-1.36]), by users of the benzodiazepine subclass (HR, 1.28 [95% CI, 1.11-1.47]), and by polytherapy compared with monotherapy (HR, 1.20 [95% CI, 1.00-1.42]) but not by anticonvulsant type (HR, 0.92 [95% CI, 0.58-1.47]). Temazepam (HR, 1.28 [95% CI, 1.01-1.62]), alprazolam (HR, 1.54 [95% CI, 1.04-2.29]), and diazepam (HR, 1.23 [95% CI, 1.06-1.41]) were significantly positively associated with fractures.

Attention to fracture prevention is important when anticonvulsants are prescribed in spinal cord injury, particularly when more than one anticonvulsant is used.