Is placebo effective in patients with low back pain?
Over three weeks, patients with long-term low back pain who knowingly took placebo twice a day reported less pain and disability than those continuing with treatment as usual. This is not the only study to show the benefit of placebo. Whether the benefit persists is not known. A nonprescription placebo (Zeebo) is available, or pharmacists can prepare placebo capsules. (Level of Evidence = 2b)
The authors enrolled 127 patients with long-term low back pain. More than 70% of enrollees reported having back pain for more than five years. The average age was 59 years and 60% were women. Initial pain scores were approximately 5 out of a possible 10, and roughly 20% of the patients were treated with analgesics at the time of enrollment. The patients were told before enrollment that the study would involve placebo treatment and were shown a video on the beneficial effects of placebo. They were then randomized, with allocation assignment unconcealed, to receive existing care or existing care plus placebo to be taken twice daily for 21 days. The patients were told it was placebo. At the end of the study, a composite pain intensity score—comprising minimum, maximum, and average pain intensities during the past seven days on an 11-point scale—dropped more with placebo treatment than with existing care alone (0.62 vs. 0.11; P = .001), and subjective disability scores improved to a greater extent with placebo (3.21 decrease vs. 0.65 increase; P = .02). Objective mobility or anxiety and stress scores were not affected. The researchers did not mask the enrolling investigator to the treatment assignment at the time of enrollment (unconcealed allocation); randomization produced an imbalance in body mass index between the groups, which might have been due to chance or to selective enrollment of patients.
Study design: Randomized controlled trial (nonblinded)
Funding source: Government
Setting: Outpatient (specialty)
Reference: Kleine-Borgmann J, Schmidt K, Hellmann A, et al. Effects of open-label placebo on pain, functional disability, and spine mobility in patients with chronic back pain: a randomized controlled trial. Pain. 2019;160(12):2891–2897.
Editor's Note: Dr. Shaughnessy is an assistant medical editor for AFP.