Correlation Between Use of Zopiclone and Risk of Hip Fracture in Elderly Adults: A Case-Control Study in Taiwan

Objectives: To investigate the correlation between zopiclone use and risk of hip fracture in elderly adults.

Design: Case-control study.

Setting: Claim data from the Taiwan National Health Insurance Program.

Participants: Individuals aged 65 and older who experienced their first episode of hip fracture between 1998 and 2011 were enrolled as the case group (n = 10,996). Randomly selected subjects aged 65 and older without hip fracture were enrolled as controls (n = 9,081). Case and control groups were matched according to sex, comorbidities, and index year of hip fracture diagnosis.

Measurements: Current users of zopiclone were defined as those whose last remaining tablet of zopiclone was detected within 7 days or less before the date of hip fracture diagnosis. Late users of zopiclone were defined as those whose last remaining tablet of zopiclone was detected more than 7 days before the date of hip fracture diagnosis. Subjects who never received a prescription of zopiclone were defined as nonusers of zopiclone. A multivariable unconditional logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to investigate the correlation between zopiclone use and risk of hip fracture.

Results: After adjusting for confounders, multivariable logistic regression analysis demonstrated that current users of zopiclone were three and a half times as likely as nonusers to experience a hip fracture (adjusted OR = 3.56, 95% CI = 2.33-4.84), whereas late users were essentially equally as likely as nonusers to experience a hip fracture (OR = 1.05, 95% CI = 0.94-1.18).

Conclusion: Current use of zopiclone was associated with greater risk of hip fracture in the elderly adults studied. Clinicians should alert elderly people to the risk of hip fracture when prescribing zopiclone.