Evaluating Therapeutic Benefit in Postsurgical Analgesia Requires Global Assessment: An Example From Liposome Bupivacaine in Hemorrhoidectomy

Abstract

Background and Objective: Interpreting analgesic efficacy based solely on measures of pain intensity can be misleading. Here, we use data from an adult hemorrhoidectomy study to demonstrate the importance of evaluating pain intensity scores with other outcome measures in interpreting analgesic study results. Methodology: We looked for coordinated outcome measures including pain intensity at rest using a numeric rating scale (NRS), postsurgical consumption of rescue medication, subject-reported results from the Brief Pain Inventory, subject satisfaction with postsurgical analgesia, and adverse events. Results: The analgesic efficacy of liposome bupivacaine was reflected in a significant reduction in pain intensity scores at each timed assessment during the first 12 to 24 hours after surgery (meanNRS at 12 hours: liposome bupivacaine, 2.2; placebo, 2.9; P = 0.04), and less consumption of opioid rescue medications thereafter through 72 hours postsurgery (mean total amount of opioids consumed: liposome bupivacaine, 10 mg; placebo, 18 mg; P = 0.0006). These observations are supported by results of other outcome measures, including time to first use of opioid rescue medication, pain-related interference of subject functionality, and subject satisfaction with postsurgical analgesia. Conclusion: Liposome bupivacaine produced superior analgesia when compared with placebo at early postoperative time points, but appropriate use of rescue medication diminished this effect after 12 hours. However, based on our assessment of multiple outcome measures used in the study, it appears that the therapeutic benefit associated with the tested analgesic lasted throughout the 72-hour study period.