A 60-year-old man with chronic back pain presents for spine surgery. According to a recent study comparing the use of conditioned open-label placebo with treatment as usual after spine surgery, which of the following outcomes is MOST likely in the conditioned open-label placebo group?
- □ (A) Lower postoperative daily opioid consumption
- □ (B) Similar worst daily pain scores
- □ (C) Lower opioid consumption in men compared to women
Placebo treatments have shown promising clinical benefits without increasing morbidity or symptoms for many pathologies. However, the deception and concealment of placebo use challenges the concept of informed consent and ethical aspect of the clinical care provided. Recently, the use of conditioned and open-label placebos has demonstrated effectiveness in treating a variety of conditions while addressing the transparency of the process and acceptance by patients. Transparent application of placebo has been studied to a limited extent in patients with chronic back pain and has shown promising results. However, it has not been previously examined in postsurgical patients, although traditional placebos have shown efficacy in this patient population.
Investigators in a recent randomized controlled trial compared conditioned open-label placebo with treatment as usual for opioid reduction after spine surgery. Patients undergoing a spinal procedure for degenerative conditions with a single surgeon were approached during their preoperative visit for enrollment. Recruitment criteria included patients aged 18 to 75 years, absence of cognitive impairment, and demonstration of English proficiency. After a detailed discussion of key study points, patients underwent bedside baseline quantitative sensory testing to assess temporal summation of pain and pressure pain threshold and tolerance. An online assessment of baseline pain characteristics was performed using the Brief Pain Inventory. In addition, an assessment of psychosocial characteristics was performed using several tools, including the Pain Catastrophizing Scale, Patient-Reported Outcome Measurement Information System short form, and the Brief Symptom Inventory 18-Somatization Scale. Although research staff and patients were not blinded to the treatment group assignments, anesthesiologists and surgical teams were blinded to the assignments.
Postoperative pain medications were prescribed by surgical teams per their clinical practice. Patients in the conditioned open-label placebo group were instructed to consume one conditioned open-label placebo pill with all analgesics (oral and/or intravenous) and record the pairing in a study diary starting on postoperative day 0. Starting on postoperative day two, patients were instructed to consume three conditioned open-label placebo pills every day at three convenient times in addition to the previously mentioned pairing. This pairing and scheduled use of conditioned open-label placebo was continued until the first follow-up appointment after discharge or postoperative day 17. Assessment of pain severity using an abbreviated version of the Brief Pain Inventory and consumption of analgesics were also recorded by patients daily in their study diary. Opioid consumption was later converted to morphine milligram equivalents (MMEs) for analysis purposes. Data from 19 patients in the conditioned open-label placebo group and 22 patients in the treatment as usual group were included in the final analysis.
The conditioned open-label placebo group consumed approximately 30% less opioids from postoperative day one to postoperative day 17 compared with the treatment as usual group (–14.5 daily MMEs; 95% CI, –26.8 to –2.2). Lower overall worst daily pain scores were also recorded in the conditioned open-label placebo group (–1.0 point on the 10-point scale; 95% CI, –2.0 to –0.1). However, no difference was found in average daily pain score (Brief Pain Inventory mean) between the two groups (–0.8 point; 95% CI, –1.7 to 0.2).
Exploratory moderation analyses of the data demonstrated that conditioned open-label placebo was more effective in lowering worst daily pain in patients with greater baseline pain, higher baseline temporal summation of pain score, and higher fibromyalgianess score. It also resulted in lower opioid consumption in women compared to men. Similarly, younger patients receiving conditioned open-label placebo experienced overall lower opioid use as well as lower worst daily pain. Of note, early discontinuation of opioid use was also evident in the conditioned open-label placebo group in the postoperative period.
In summary, the use of conditioned open-label placebo in reducing postoperative opioid consumption seems promising. Although the underlying mechanism by which conditioned open-label placebo works is still unclear, its demonstrated effect on daily opioid use, worst daily pain score, and early discontinuation of opioid analgesics provides the basis for future research and potential use as an analgesic adjuvant.
Summaries of Emerging Evidence (SEE) is a self-study CME program that highlights emerging knowledge in the field of anesthesiology. The program presents relevant topics from more than 30 of today’s leading international medical journals in an engaging question-discussion format. SEE can be used to help fulfill the CME requirements of MOCA®. To learn more and to subscribe to SEE, visit: asahq.org/SEE.
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