Limited evidence that ‘mild’ hyperbaric therapy benefits autistic spectrum disorder

Clinical bottom line: Oxygen at the equivalent of 31% at sea level did not result in higher scores on a clinical assessment scale in autism spectrum disorder.

Citation/s:
ROSSIGNOL, D.A. et al. Hyperbaric treatment for children with autism: a multicenter, randomised, double blind, controlled trial. BMC Paediatrics 2009;9:21

Three-part Clinical Question: In children with Autistic Spectrum Disorder, does the administration of mild hyperbaric oxygen improve functional ability?
Search Terms: autism; autistic spectrum disorder.

The Study:
Double-blind concealed randomised controlled trial with intention-to-treat.
The Study Patients: Children aged 2 to 7 with Autistic Disorder meeting DSM-IV criteria
Control group (N = 29; 26 analysed): Sham HBOT with 60 mins 21% 02 at 1.03ATA in monoplace chamber. Two treatments per day for 40 sessions total
HBOT group (N = 33; 30 analysed): 0.24% 02 at 1.3 ATA on the same schedule.

The Evidence:

Outcome

Time to Outcome

Control

HBOT

Relative risk reduction

Absolute risk reduction

NNT

Clinical global index (physician) less than ‘much improvement’

4 weeks

0.83

0.66

23%

0.19

5

95% CI:

-3% to 49%

-0.02 to 0.41

NNT = 2 to INF; NNH = 45 to INF

Clinical global index (parental) less than ‘much improvement’

4 weeks

0.76

0.64

16%

0.12

8

95% CI:

-14% to 46%

-0.10 to 0.35

NNT = 3 to INF; NNH = 10 to INF

 

Non-Event Outcomes

Time to outcome

Control group

HBOT group

P-value

Total Autism Behaviour Checklist score

4 weeks

45.5

46.4

0.41

Total Autism Treatment Evaluation Checklist score

4 weeks

70.1

65.9

0.20

Comments:
1. There was improvement in both treatment and control groups suggesting a strong placebo or Hawthorne effect.
2. Main outcome reported in the paper was improvement in scores rather than absolute difference after therapy.
4. One centre lost 30% of ATEC scores due to an administrative error.
5. Not a test of HBOT as an Fi02 of 0.24 at 1.3 ATA is equivalent to 31% oxygen at sea level.
6. No compensation of these low pressures for altitude, so that patients at one of the participating centres were exposed to little more than 1ATA in the active treatment arm.  

Appraised by: Mark Fisher Dept of Diving and Hyperbaric Medicine, Prince Of Wales Hospital, Randwick, SYDNEY Australia; Friday, 26 March 2010
Email: mark.fisher@sesiahs.health.gov.nsw.au
Kill or Update By: March 2012