Objective: A pilot study to assess the feasibility of a trial to investigate the efficacy of acupuncture compared to placebo needling for the treatment of acute low back pain (LBP). As part of this, the study was designed to establish the credibility of the placebo control, and to provide data to inform a power analysis to determine numbers for a future trial.
Study design: A pilot patient and assessor blinded randomized controlled trial.
Setting: Primary care health centre facility, South and East Belfast Trust, Northern Ireland.
Patients: Patients from the physiotherapy waiting list (n=48) with LBP of less than 12 weeks duration.
Outcome measures: Roland and Morris Disability Questionnaire (RMDQ), Visual Analogue Scale (VAS), medication use and an exit questionnaire were completed at baseline, end of treatment, and at 3 months follow up.
Results: Ninety-four percent (45/48) of patients completed assigned treatment, 83% (40/48) completed 3 months follow-up. The sham needle used here proved to be credible: 91.7% in the placebo group believed they had received acupuncture, compared to 95.8% in the verum acupuncture group. Differences in baseline characteristics were accounted for using ANCOVA. There was no significant difference between groups on the RMDQ over time. For pain, the only statistically significant difference was at the 3 months follow up (worst VAS, point estimate, 18.7, 95% CI 1.5-36.0, p=0.034). The majority of patients were taking some form of analgesic medication for LBP at the start of treatment (n=44; 92%), and at the end of treatment the verum acupuncture group were taking significantly fewer tablets of pain control medication (mean (S.D.): 1.0+/-0.3) than the placebo group (mean (S.D.): 4.2+/-0.6, p<0.05). Based upon these data, power analysis (power=90%, alpha=0.05, minimal clinically important difference (MCID) for RMDQ=2.5 points) indicated that 120 participants (60 per group) would be needed to complete an adequately powered randomized controlled trial.
Conclusions: This study has demonstrated the feasibility of a randomized controlled trial of penetrating needle acupuncture compared to a non-penetrating sham for the treatment of acute LBP in primary care; 120 participants would be required in a fully powered trial. The placebo needle used in this study proved to be a credible form of control.