Impact of insomnia on postoperative pain: a case-control study

Abstract

Introduction: Psychological factors play a significant role in predicting postoperative pain. However, the impact of insomnia on acute postoperative pain is little known. The aim of this study was to investigate the relationship between insomnia and acute postoperative pain. Material and Method: We performed a case-control study in patients undergoing elective laparoscopic cholecystectomy. Patients with an Insomnia Severity Index (ISI) score >14 were allocated to an insomnia group (n=35) and those with an ISI score <7 to a control group (n=35). All patients were asked to rate their current level of pain on a numeric rating scale (NRS) at 1, 2, 4, 8, 12, and 18 hours postoperatively. Results: There was no between-group differences in age, gender, body mass index, American Society of Anesthesiologists score, or operating time. The patients in the insomnia group had higher NRS scores and requested significantly greater amounts of tramadol (269.4 ± 33 mg vs. 235.0 ± 36 mg; p<0.001) and rescue analgesia (paracetamol; 1.06 ± 0.8 g vs. 0.40 ± 0.7 g; p<0.001) postoperatively than did the controls. Analysis of covariance revealed a significant interaction between insomnia and the preoperative experience of pain (F=6.62; p=0.013) and significant impact of insomnia on the mean NRS score (F=15.47; p<0.001). Conclusion: Our study findings indicate that insomnia may be a significant predictor of acute postoperative pain in patients undergoing cholecystectomy as an elective procedure