Background/Purpose: Anticonvulsants are commonly used to manage neurological and psychiatric disorders such as epilepsy, migraines and bipolar disorder. These medications are often prescribed long-term, and in some cases, lifelong. Prolonged anticonvulsant use has been associated with an increased risk of fractures in adults and lower bone mineral density in children, likely due to their effect on bone metabolism. This study aimed to investigate the association between fracture risk and anticonvulsant use in each group of patients who are currently taking anticonvulsants with those who have previously used them.

Methods: This retrospective study was conducted at a district general hospital in the northwest of England, from July 2004 to February 2024. There were 1,368 patients, with 332 patients who were previous anticonvulsant users and 1,036 patients who were current anticonvulsant users. In both groups, the predictors of fracture risk were examined, including age, gender, height, weight, body mass index (BMI), percentage total body fat, current smoker, current alcohol drinker, current steroid use, previous fractures and bone mineral density (BMD) values at the L1-L4 vertebrae, right and left femur neck, and right and left femur total. These factors were compared between the two groups of current and previous anticonvulsant users using independent t-tests for continuous factors and chi-square tests for categorical factors. A logistic regression model was used to assess the relationship between anticonvulsant use (current and previous users) and fracture risk (history of fracture), taking into account the predictors of fracture.

Results: The mean age was 65, and 87% were female in both groups. Initially the predictors of fracture were compared between current and previous anticonvulsant users; right and left femur neck and total BMD were found to be significantly lower in current anticonvulsant users (P< 0.05). In the first logistic regression analysis, the fracture risk was assessed in previous and current anticonvulsant users, taking into account the predictors of fracture. Current anticonvulsant users were associated with increased odds of fracture (OR = 1.48, 95% CI: 1.06–2.07, p = 0.020). Another independent factor, percentage total body fat, was also found to be significantly associated with fracture (p = 0.007). Second logistic regression analysis examined the interaction between anticonvulsant use and percentage body fat, which was not found to be significant (p = 0.288). This suggests that percentage body fat did not significantly change the association between anticonvulsant use and fracture risk.

Conclusion: In conclusion, the results show current anticonvulsant use is associated with an increased fracture risk, compared to previous users. In addition, the current anticonvulsant users were found to have lower femur neck and femur total BMD, which is likely to have an increased risk for major fractures. Percentage total body fat was an independent factor which was found to be a significant predictor of fracture risk.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/risks-of-fracture-in-current-and-previous-anticonvulsant-users-an-observational-study/