Evaluation of postoperative delirium in geriatric patients given acetaminophen with and without melatonin: A retrospective cohort study

ObjectivePostoperative delirium has many consequences and must be prevented when possible. Non-opioid pain treatments may help to prevent, and melatonin has also been shown to prevent delirium in non-surgical populations. The incidence of postoperative delirium was retrospectively compared in patients prescribed acetaminophen with and without melatonin following orthopedic surgery.MethodsRetrospective data were analyzed in adults ≥ 65-years-old hospitalized in one health system following an orthopedic procedure. Patients receiving at least acetaminophen 1000 mg/day with and without melatonin 1 mg/day for at least 48 hours perioperatively were included. To reduce confounders, patients were excluded if they had prior delirium, an intensive care unit placement >24 hours, or other risk factors for developing delirium. The primary outcome was a positive CAM-ICU score indicating delirium. Key secondary endpoints included hospital length of stay and 30-day hospital readmission.ResultsTwo hundred patients were assessed, and 134 patients were included in the analysis (i.e., 66 receiving acetaminophen plus melatonin vs. 68 receiving acetaminophen alone). The rate of delirium was significantly lower in those receiving the combination vs. acetaminophen alone (5% vs. 25%, <i>P</i> = 0.001). There were no differences in 30-day readmission. Patients taking the combination had a longer length of stay than those taking acetaminophen alone (5 days vs. 4 days, <i>P</i> = 0.04).ConclusionGeriatric patients taking acetaminophen plus melatonin after orthopedic surgery had a significantly lower risk of delirium compared to patients receiving acetaminophen alone. Using a combination melatonin and acetaminophen before orthopedic surgery is a promising strategy for preventing delirium and should be considered in future prospective trials.