Patients
with retinitis pigmentosa who received hyperbaric oxygen did not show
deterioration in electroretinographic response (ERG), and a small proportion
improved.
Clinical
Bottom Line:
1.
HBO administration prevented deterioration in electroretinographic responses
over 3 years.
2. HBO administration increased mean electroretinographic responses over the 3 years of the study, but only a small proportion of subjects improved.
Citation:
1.
Vingolo E, Pelaia, Forte R. Rocco M, Giusti C, Rispole E. Does hyperbaric oxygen
(HBO) delivery rescue retinal photoreceptors in retinitis pigmentosa? Documenta
Opthalmologica 97: 33-39, 1999
Three-part
Clinical Question: For patients with retinitis
pigmentosa, does hyperbaric oxygen therapy (when compared to no treatment)
modify electroretinographic
responses?
Search
Terms: hyperbaric oxygenation,
retinitis pigmentosa
The
Study:
Non-blinded
randomised controlled trial with intention-to-treat.
The
Study Patients: A diagnosis of
retinitis pigmentosa with clearly identified inheritance. Specific criteria
and electroretinographic (ERG) data were utilised to aid diagnosis.
Control
group (N = 24; 24 analysed): No specific treatment.
Experimental
group (N = 24; 24 analysed): Hyperbaric oxygen therapy (Schedule: 100% O2 at 2.2
ATA for 90 mins). 1st month: 5 treatments per week. Next 11 months: one week of
treatments per month. Year 2 and 3: one week of treatments every 3 months.
The Evidence:
|
Outcome |
Time
to Outcome |
Control
group |
Hyperbaric
group |
Relative
risk reduction |
ARR |
NNT |
|
ERG
improved |
3
years |
0 |
.11 |
INF |
-0.11 |
9 |
|
95% CI: |
|
|
|
|
-0.24
to 0.02 |
NNT
= 4 to INF NNH = 66 to INF |
|
ERG
deteriorated |
3
years |
0.62 |
0 |
100% |
0.62 |
2 |
|
95% CI: |
|
|
|
|
0.43
to 0.81 |
1
to 2 |
|
Measure |
Control
Group Mean |
SD |
HBO
Group Mean |
SD |
Difference |
95%
CI |
|
ERG b-wave amplitude in microV
at 1 year |
5.04 |
3.07 |
8.46 |
5.71 |
3.42 |
0.76
to 6.09 |
|
ERG b-wave amplitude in microV
at 2 years |
3.46 |
2.77 |
10.7 |
7.6 |
7.24 |
3.92
to 10.57 |
|
ERG b-wave microV at 3 years |
2.97 |
3.61 |
14.4 |
11.7 |
11.43 |
16.46
to-6.40 |
Comments:
1.
Small study with highly defined patient population. Severely affected
individuals were excluded.
2.
This study suggests that treatment with HBO will prevent ERG deterioration in 1
out every 2 patients over 3 years.
3.
Visual acuity was not estimated in this study and ERG response may not equate
with important changes in visual acuity.
Appraised
by: Juliette Leverment and Mike Bennett
Prince
of Wales Hospital, Sydney; Friday, 6 December 2002
Email:
jullietteleverment@hotmail.com
Kill
or Update By:
October 2003