Risk of bone fractures in patients with narcolepsy: a nationwide population-based cohort study

Narcolepsy symptoms, such as excessive daytime sleepiness or cataplexy, can pose a risk to safety. Stimulants or antidepressants have been used to treat these symptoms. The study investigated the risk of bone fractures in narcolepsy patients. Also, the exposure pattern of stimulants and antidepressants to the risk of bone fractures was examined.

In all, 493 narcolepsy patients and 490 controls matched by gender, age, index year, and comorbidity severity were enrolled between 1998 and 2012, then followed until the end of 2013 using Taiwan's National Health Insurance Research Database. During the follow-up period, participants who developed bone fractures were identified. Cox regression analysis was used to calculate the hazard ratio (HR) with 95% confidence interval (CI) for the incidence rates of bone fractures between narcolepsy patients and unaffected controls.

Narcolepsy patients had a significantly increased risk of bone fractures compared with unaffected controls (19.6 versus 12.3 per 1000 person-years, HR: 1.74, 95% CI: 1.29-2.35). In addition, the use of stimulants in narcolepsy patients showed lower incidence rates of bone fractures compared to non-users (incidence rates were 14.2, 11.9, and 20.0 per 1000 person-years, respectively, among frequent users, infrequent users, and non-users), but the risk estimate was not statistically significant. The evidence for associations between antidepressant use in narcolepsy patients and bone fractures was contradictory.

This study highlights the need to pay attention to the risk of bone fractures in narcolepsy patients, and the importance of adequate stimulants use might reduce the risk of bone fractures.