Anxiety, but not pain catastrophizing, represents a risk factor for severe acute postoperative pain: a prospective, observational, cohort study

Abstract

Abstract Introduction: The prevalence of severe acute postoperative pain (SAPP), i.e. pain intensity > 5/10 measured with Numeric Rating Scale (NRS), is still high, 24-46% in Western European countries and 64% in Republic of Moldova. Objective of the study: We tested the hypothesis that anxiety and pain catastrophizing perception (interpreted as hypervigilance) represent risk factors for SAPP. Materials and methods: 176 patients scheduled for abdominal surgery under general anaesthesia were enrolled in this study, after approval by the University’s Research Ethics Committee and after obtaining patient written informed consent. Preoperatively, all patients filled a Pain Catastrophizing Scale (PCS) questionnaire and self-assessed the anxiety level on a numeric rating scale that was bounded by 0 (denoting no anxiety) and 10 (denoting maximal imaginable anxiety). Duration of surgery, intraoperative administration of fentanyl and pain intensity at 24 hours postoperatively on NRS was also recorded. Statistical analysis comprised the following tests: odds ratio (OR), relative risk (RR), positive and negative predictive values (PPV and NPV, respectively), likelihood ratio, receiver operating characteristic (ROC) curves, and Pearson correlation test. Results: “Hypervigilant” patients did not show an increased risk for SAPP based on histogram calculations (OR = 1.51 [95CI = 0.62-3.65], p = 0.39). However, based on ROC curve calculations (OR = 2.34 [1.13- 4.83], p = 0.0029), these patients showed a risk for SAPP. On average, anxiety determined a fivefold increase of the SAPP risk (OR = 5.1 [95CI = 1.44-18.50], p = 0.011). Intraoperative fentanyl consumption had a weak but significant correlation with pain intensity at 24 h postoperatively (Pearson r = 0.26; p = 0.0008). Surgery duration did not correlate with pain intensity (Pearson r = -0.10; p = 0.46). Conclusion: Anxiety, but not pain catastrophizing, represents a risk factor for SAPP. Intraoperative fentanyl consumption had a weak correlation with postoperative pain intensity