Effect of midazolam on delirium in critically ill patients: a propensity score analysis

OBJECTIVE: To observe the association between exposure to midazolam within 24 hours prior to delirium assessment and the risk of delirium. METHODS: We performed a systematic cohort study with two sets of cohorts to estimate the relative risks of outcomes among patients administered midazolam within 24 hours prior to delirium assessment. Propensity score matching was performed to generate a balanced 1:1 matched cohort and identify potential prognostic factors. The outcomes included the odds of delirium, mortality, length of intensive care unit stay, length of hospitalization, and odds of being discharged home. RESULTS: A total of 78,364 patients were included in this study, of whom 22,159 (28.28%) had positive records. Propensity matching successfully balanced covariates for 9348 patients (4674 per group). Compared with no administration of midazolam, midazolam administration was associated with a significantly higher risk of delirium, higher mortality, and a longer intensive care unit stay. Patients treated with midazolam were relatively less likely to be discharged home. There was no significant difference in hospitalization duration. CONCLUSIONS: Midazolam may be an independent risk factor for delirium in critically ill patients.