Zolpidem Use and Suicide Death in South Korea: A Population-Based Case-Control Study

Objective To investigate whether zolpidem use is associated with suicide death in adults. Method We conducted a case-control study using the National Health Insurance Service-National Sample Cohort (NHIS-NSC) database. Cases were adults with a suicide record (ICD-10 codes; X-60-X84, Y87.0) between January 1, 2004 and December 31, 2013. 10 Controls were matched to each case by age, sex, index year, region, income level, and health insurance type. Zolpidem use during 2 years before suicide was quantified. Adjusted odd ratios (aORs) with 95% confidence intervals (CIs) were estimated using conditional logistic regression. Results The percentage of zolpidem users was significantly higher in cases (451 of 1,928 [23.4%]) than in controls (832 of 18,404 [4.5%]). After controlling for potential confounders, zolpidem use was significantly associated with suicide (aORs, 2.09; 95% CI, 1.74-2.52). Dose-response relationships were observed (for trend, p < .0001). Consistent findings were observed when analyses were restricted to suicide death (aORs, 2.08; 95% CI, 1.73-2.51) and nonmedication poisoning suicide death cases (aORs, 2.10; 95% CI, 1.74-2.53). Conclusions We found a significant and positive association between zolpidem use and suicide. Zolpidem should be prescribed cautiously and with due caution of increased suicide risk.