Hyperbaric oxygenation did not exert a prophylactic effect on migraine

1. HBOT did not significantly decrease hours of migraine headache in the 8 weeks following treatment.
2. No apparent effect on a marker of vasoconstriction (endothelin-1). Significance unknown.

Citation/s:
1. Eftedal OS, Lydersen S, Helde G, White L, Brubakk AO, Stovner LJ. A randomised, double-blind study of the prophylactic effect of hyperbaric oxygen therapy on migraine. Cephalalgia 2004; 24:639-644
Lead author's name and fax: Lars Stovner: lars.stovner@medisin.ntnu.no

Three-part Clinical Question: In migraneurs, does the addition of prophylactic hyperbaric oxygenation to usual therapy reduce time spent with headache?
Search Terms: migraine, endothelin

The Study:
Double-blinded concealed randomised controlled trial without intention-to-treat.
The Study Patients: Migraneurs with 2 to 8 attacks each month for three months prior to enrolment.
Control group (N = 20; 15 analysed): Air breathing at 2 ATA for 30 minutes daily for 3 days.
Experimental group (N = 20; 19 analysed): As above but 100% oxygen breathing

The Evidence:

 

Measure

Control Group

HBOT Group

Difference

95% CI

Mean

SD

Mean

SD

Change in headache, before versus after therapy (week one, hrs)

-0.6

 

-4.0

 

3.4

 

Change in headache before versus 8 weeks after therapy (hrs)

-5.0

 

+4.4

 

-9.4

 

Endothelin-1 plasma levels after 3 treatments (pg/ml)

0.81

0.27

0.75

0.13

0.06

-0.08 to 0.20

 

Outcome

Time to Outcome

Control Rate

HBOT rate

Relative risk reduction

Absolute risk reduction

Number needed to treat

Acute headache resolution during therapy

During therapy

0.36

0.42

9%

0.06

17

95% Confidence Intervals:

-49% to 68%

-0.32 to 0.44

NNT = 2 to INF; NNH = 3 to INF

 

Comments:
1. Small study, no power or sample size calculation.
2. Unusual hyperbaric regimen and above normal inspired oxygen tension in control group.
3. Results given do not allow full evaluation and some values are read from a graph
4. An analysis investigating the duration of any possible treatment effect for HBOT did not suggest any significant benefits. Validity unknown.
5. No treatment sparing effect noted (no results given).

Appraised by: Sean Hopson and Mike Bennett, Prince of Wales Hospital, Sydney ; Friday, 8 September 2006
Email: sean@thegasman.org
Kill or Update By: September 2007