Open-label placebo injection demonstrates ‘modest’ benefit in chronic back pain
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Key takeaways:
- A non-deceptive placebo injection reduced chronic back pain with effect size similar to typical treatments.
- Secondary outcome benefits and brain changes lasted up to 1 year.
A single saline injection, openly prescribed as a placebo, yielded approximately 1 month of chronic back pain improvement, along with longer-term benefits in depression and sleep, according to data published in JAMA Network Open.
“We have known that placebos can be powerful pain relievers, but it has been unclear how to use them ethically, without patient deception,” Yoni K. Ashar, PhD, assistant professor at the University of Colorado Anschutz Medical Campus, told Healio. “This spurred the development of the ‘open label,’ non-deceptive placebo treatment, which we studied here.”
To investigate the long-term efficacy of open label placebo in chronic back pain, Ashar and colleagues recruited 101 adults (mean age, 40.4 years) with moderate chronic back pain from the Boulder, Colorado, area between November 2017 and August 2018, with a follow-up at 1 year.
Trial participants were randomly assigned to either continue their usual care alone or to also receive a single, open label lumbar saline injection, along with information about how the placebo effect can lead to pain relief. The primary outcome was average pain over the last week 1 month after treatment, measured using a scale of 0 to 10. Secondary outcomes also assessed pain interference, depression, anxiety, anger and sleep quality.
At 1 month, those who received placebo injections reported greater reductions in chronic back pain than the usual care group (relative reduction, 0.61; Hedges g = 0.45; 95% CI, –0.89 to 0.04), according to the researchers.
By 1 year post-treatment, the between-group difference in pain relief was reduced to insignificance. However, after 1 month, other significant benefits were seen in depression, anger, anxiety and sleep disruption, with “medium sized” effect sizes ranging from 0.3 to 0.5 (P < .03 for all).
The researchers also compared neuroimaging between the groups. Functional MRI scans were taken as participants performed both an “evoked” back pain procedure, which used an inflating balloon to cause back distention and pain, and a “spontaneous” pain procedure, where patients rated their pain once per minute over the course of an 8-minute scan.
Overall, the neuroimaging showed “altered brain responses to evoked back pain and altered functional connectivity during spontaneous pain consistent with engagement of descending modulatory pain pathways,” Ashar and colleagues wrote.
The researchers described the placebo injection’s pain relief benefit as “modest in magnitude” but clinically significant and comparable with the effect sizes of typical treatments such as NSAIDs, but with fewer adverse events.
“These findings speak to the power of healing rituals, even when we know they are healing rituals,” Ashar said. “Although we view this study as more mechanistic and conceptually provocative than as clinically applicable, it suggests that providers may be able to ethically prescribe a placebo for their patients one day, without deception. In addition, the duration of benefits on secondary outcomes and the observed brain changes were surprising, considering how brief and minimalist the intervention was.”
For more information:
Yoni K. Ashar, PhD, can be reached at yoni.ashar@cuanschutz.edu; X (Twitter): @YoniAshar.
Perspective
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The power of placebo treatments is well recognized and has shown benefit in a variety of heterogeneous conditions, ranging from cancer-related fatigue to migraines, musculoskeletal pain, irritable bowel syndrome, and even cardiovascular conditions such as angina.
In this randomized clinical trial, Ashar and colleagues demonstrated the efficacy of a one-time, open-label, non-deceptive placebo subcutaneous saline injection to patients suffering from chronic back pain. The intervention for the patients in the treatment arm included an educational component describing the therapeutic benefits and potential mechanisms for the efficacy of placebo treatments (ie, via the release of endogenous opioids).
The investigators also demonstrated activation of the prefrontal-brainstem pain modulatory pathways — similar brain activity seen when deceptive placebos are used on study participants.
Although durable improvements did not occur in pain measurements, other quality-of-life measurements, including ratings of depression, anxiety, sleep and anger, did persist to the study endpoint.
Some of the limitations of the present study include a non-heterogenous study population and a limited sample size. The participants were generally experiencing only moderate amounts of pain at baseline (ie, 4/10), very few were on opiates and most were capable of exercising several times weekly.
Additionally, the investigators excluded any patients with a history of autoimmune disease. To determine the generalizability of the authors’ findings to the typical rheumatology practice, a larger sample size, and a more heterogeneous population, including patients with both autoimmune disease and more significant impairments, would be necessary.
Despite tremendous advances in the management of inflammatory and systemic autoimmune diseases, ubiquitous and often debilitating conditions like osteoarthritis and chronic low back pain remain without disease-modifying agents or highly effective treatment options. This paper highlights one potential intervention that, if further validated in more extensive studies, could help ameliorate some of our patients’ suffering.
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