The Influence of Baseline Characteristics on Response to a Laser Acupuncture Intervention: An Exploratory Analysis

Abstract

Objectives In clinical practice it is known that subjects vary in their response to acupuncture, but there is little data on what predicts the outcome. The aim of this study was to identify such predictors. Method A secondary analysis was performed on data from 100 participants in a trial of laser and sham laser acupuncture for chronic non-specific low back pain. Multiple regression analysis was used to identify which baseline characteristics predicted pain change in the immediate, short and intermediate term. An analysis of covariance was performed based on these results to re-examine the primary result of the trial. Results Strong predictors of poor response were receipt of disability support pension, headache, the regular use of analgesics or previous failed back surgery. Higher pain scores or exacerbation of pain at baseline predicted a greater proportionate pain relief after the intervention. Adjusted analysis suggested a clinically important effect of laser compared to sham (p<0.05), at short term follow-up only. Conclusion The findings of this study suggest which characteristics of patients with chronic low back pain are more likely to respond to laser acupuncture treatment, but require replication in other studies. The findings may not apply in other acupuncture interventions and treatment of different conditions. They may also be used to set selection criteria for future studies, and to aid interpreting the effect of baseline imbalances on trial results.

Laser Acupuncture for Treating Musculoskeletal Pain: A Systematic Review with Meta-analysis

“…The pooled effect sizes of laser acupuncture for pain were considered to be small at short-term follow-up, but showed a moderate effect at long-term follow-up (see Appendix 4). Other studies [40,41,44,47,48,50,54,57,61,62,74,80] expressed the pain change scores from baseline, and showed a similar effect on pain relief at both short-term (SMD À0.53; À0.95 to À0.10) and long-term follow-ups (SMD À0.77; À1.25 to À0.29). When compared with other interventions, results of pain scores were mixed.…”

“…This apparent error was also highlighted by another systematic review [83], which suggested a flaw in their analysis. In another study on back pain, Glazov and colleagues [41] performed a post hoc analysis on their data, which challenged the results of their original study [46]. They suggested that the randomization failed to create comparable groups and resulted in an imbalanced baseline characteristic that responded differently to the intervention.…”

Low-Dose Laser Acupuncture for Non-Specific Chronic Low Back Pain: A Double-Blind Randomised Controlled Trial

“…A small trial using an infrared laser (1.1 J/point)19 detected a significant improvement in only one of many pain outcomes measured. Subsequently, the results of another larger trial20 using a 10 mW infrared laser (0.2 J/point) were negative, although questions were raised regarding the possibility of insufficient dosage21 and of confounding baseline factors 22. An adjusted analysis showed a benefit for this dose at 6 weeks.…”

Explore Laser Acupuncture’s Role

“…They found that higher pain scores at baseline predicted greater pain relief after LA for chronic non-specific low back pain. Adjusted analysis suggested a clinically significant effect on pain with LA compared to sham treatment (P < 0.05), at short term follow-up only [6]. Later, Glazov et al performed a randomized controlled trial comparing the effects of laser acupuncture (LA) and sham laser treatment in reducing pain and disability in adults with chronic non-specific low back pain.…”