When used by itself, a single outcome measure cannot provide the complete picture regarding therapeutic benefit when evaluating the effect of an analgesic in a placebo controlled clinical study where rescue medication is allowed. This paper provides a rationale for the use of multiple outcome measures to gauge therapeutic benefits of analgesics for postsurgical pain. As an example, Schmidt and colleagues re-assessed pain intensity scores, rescue opioid use, functionality scores, and patient satisfaction from a study in excisional hemorrhoidectomy patients who were treated with a single intraoperative administration of a prolonged-release analgesic formulation, liposome bupivacaine (n=95), or placebo (n=94). All patients had access to rescue analgesics if needed. Compared to the placebo patients, average pain intensity scores were significantly lower in the liposome bupivacaine group for all time points up to the first 24 hours after surgery, but not from 24 to 72 hours. By contrast, assessments obtained from 12 to 72 hours after surgery showed that the therapeutic benefit was reflected in significantly lower amounts of opioids consumed. Other metrics supporting the presence of a therapeutic benefit for the liposome bupivacaine through 72 hours postsurgery included: a higher proportion of patients remaining opioid-free; a longer duration of time from end of surgery to first use of opioid rescue medication; scores on the patient-functionality assessment (Brief Pain Inventory) reflecting less pain-related interference with mood, walking ability, and work; and greater patient satisfaction with postsurgical analgesia. The authors concluded that use of multiple outcome measures provides a more meaningful picture of the therapeutic effects of an analgesic medication in the postsurgical setting than measurement of pain intensity alone.
Evaluating therapeutic benefit in postsurgical analgesia requires global assessment: an example from liposome bupivacaine in hemorrhoidectomy.
Hospital practice (1995) 2012 Feb 1; 40(1):160-5
Schmidt WK, Patou G, Joshi P
President, NorthStar Consulting, LLC, Davis, CA 95616, USA. email@example.com
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.
Keywords: liposome bupivacaine