The Effect of Melatonin on Early Postoperative Cognitive Decline in Elderly Patients Undergoing Hip Arthroplasty: A Randomized Controlled Trial

Abstract

Copyright © 2017 Wolters Kluwer rate POCD. Exogenous melatonin improves sleep quality in patients with primary sleep disorders and can improve cognitive dysfunction in adults with mild cognitive impairment. This prospective cohort study aimed to determine whether melatonin can ameliorate early POCD in elderly hip arthroplasty patients. The study included 139 American Society of Anesthesiologists grades I to III patients older than 65 years scheduled for hip arthroplasty with spinal anesthesia. Patients were randomized to receive either 1 mg oral melatonin or placebo daily 1 hour before bedtime 1 day before surgery and for another 5 consecutive days postoperatively. Subjective sleep quality, generalwell-being, postoperative fatigue, visual analog scale for pain, and cognitive function (using Mini Mental State Examination [MMSE]) were evaluated preoperatively and at days 1, 3, 5, and 7 postoperatively. Statistical analysis was performed using the SPSS 16.0 software forWindows (SPSS, Chicago, Ill), and P < 0.05 was considered to be statistically significant. The MMSE score in the melatonin group did not change during the 7 days of monitoring after surgery, but in the control group, the MMSE score decreased significantly at days 1, 3, and 5 after surgery when compared with its own preoperative value and with the melatonin group value for the corresponding date (P < 0.05). A significant postoperative impairment of subjective sleep quality (F statistic estimate of variation [F] = 7.95, P < 0.05), general well-being (F = 5.791, P < 0.05), and fatigue (F = 8.333, P > 0.05) was found in the control group when compared with the melatonin group. In conclusion, perioperative melatonin supplementation improved preoperative sleep quality, thus confirming that exogenous melatonin can improve early POCD. Further studies are required to evaluate the effects of comorbidities and medication usage on melatonin's role in improving cognitive dysfunction.