Some evidence for placebo improvement in anxiety and depression scores following sham hyperbaric therapy in patients with diabetic ulcers.

Clinical Bottom Line:
1. No evidence for improvement from placebo treatment on general health status questionnaire SF-36.
2.Hospital anxiety and depression scales suggest reduction in depression and anxiety following placebo treatment.

Appraised by: Mike Bennett, Dept. of Diving and Hyperbaric, Prince of Wales Hospital
Sydney ; Monday, 14 January 2002. Email:

Three-part Clinical Question: For patients undergoing hyperbaric therapy, is there an identifiable placebo effect, resulting in some measure of at least subjective improvement?
Search Terms: hyperbaric oxygenation, placebo effect, trial design

The Study:
Double-blinded randomised controlled trial intention-to-treat unknown.
The Study Patients: Patients with diabetic foot ulcers who were enrolled in a randomised controlled trial.
Control group (N = 9;? analysed): Air at 2.4ATA for 90 minutes daily for a total of 30 treatments.
Experimental group (N = 9;? analysed): 100% oxygen at 2.4ATA on the same schedule.

The Evidence:
Non-Event Outcomes Time to outcome/s Control group HBO group
Hospital anxiety and
depression scale- depression 30 days Reduced (P=0.001) Reduced (P=0.001)
- anxiety Reduced (P=0.025) Unchanged

SF-36 - 5/8 domains 30 days Unchanged Unchanged
- General Health Improved Unchanged Improved (P=0.008)
- Health Transition Unchanged Improved (P=0.04)

1. True significance of these findings is not clear
2. Abstract only, so little methodological or outcome detail.
3. Probably represents the same group of patients as this author’s diabetic patient RCTs

Kill or Update By: January 2004

1. Abidia A, Kuhan G, Laden G. The placebo effect of hyperbaric oxygen therapy- fact or fiction? Undersea and Hyperbaric Medicine 2001; 28(suppl):57-58.