Further evaluation of docosahexaenoic acid in patients with retinitis pigmentosa receiving vitamin A treatment: subgroup analyses.

Abstract

OBJECTIVE:

To determine whether docosahexaenoic acid will slow the course of retinal degeneration in subgroups of patients with retinitis pigmentosa who are receiving vitamin A.

DESIGN:

A cohort of 208 patients with retinitis pigmentosa, aged 18 to 55 years, were randomly assigned to 1200 mg of docosahexaenoic acid plus 15 000 IU/d of vitamin A given as retinyl palmitate (DHA + A group) or control fatty acid plus 15 000 IU/d of vitamin A (control + A group) and followed up over 4 years. Seventy percent of the patients in each group were taking vitamin A, 15 000 IU/d, prior to entry. We compared rates of decline in ocular function in the DHA + A vs control + A groups among the subgroups defined by use or nonuse of vitamin A prior to entry. We also determined whether decline in ocular function was related to red blood cell phosphatidylethanolamine docosahexaenoic acid level, dietary omega-3 fatty acid intake, or duration of vitamin A use. Main outcome measures were Humphrey Field Analyzer visual field sensitivity, 30-Hz electroretinogram amplitude, and visual acuity.

RESULTS:

Among patients not taking vitamin A prior to entry, those in the DHA + A group had a slower decline in field sensitivity and electroretinogram amplitude than those in the control + A group over the first 2 years (P =.01 and P =.03, respectively); these differences were not observed in years 3 and 4 of follow-up or among patients taking vitamin A prior to entry. In the entire cohort, red blood cell phosphatidylethanolamine docosahexaenoic acid level was inversely related to rate of decline in total field sensitivity over 4 years (test for trend, P =.05). This was particularly evident over the first 2 years among those not on vitamin A prior to entry (test for trend, P =.003). In the entire control + A group, dietary omega-3 fatty acid intake was inversely related to loss of total field sensitivity over 4 years (intake, <0.20 vs > or =0.20 g/d; P =.02). The duration of vitamin A supplementation prior to entry was inversely related to rate of decline in electroretinogram amplitude (P =.008).

CONCLUSIONS:

For patients with retinitis pigmentosa beginning vitamin A therapy, addition of docosahexaenoic acid, 1200 mg/d, slowed the course of disease for 2 years. Among patients on vitamin A for at least 2 years, a diet rich in omega-3 fatty acids (> or =0.20 g/d) slowed the decline in visual field sensitivity.

• Authors: Eliot L Berson, Bernard Rosner, Michael A Sandberg, Carol Weigel-DiFranco, Ann Moser, Robert J Brockhurst, K C Hayes, Chris A Johnson, Ellen J Anderson, Alexander R Gaudio, Walter C Willett, Ernst J Schaefer
• Journal: Archives of ophthalmology (Chicago, Ill. : 1960) (Arch Ophthalmol) Vol. 122 Issue 9 Pg. 1306-14 (Sep 2004) ISSN: 0003-9950 [Print] United States
• PMID: 15364709 (Publication Type: Clinical Trial, Comparative Study, Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Phosphatidylethanolamines
• Vitamin E
• Docosahexaenoic Acids
• phosphatidylethanolamine

Topics

• Administration, Oral
• Adolescent
• Adult
• Docosahexaenoic Acids (metabolism, therapeutic use)
• Double-Blind Method
• Drug Therapy, Combination
• Electroretinography
• Erythrocyte Membrane (metabolism)
• Female
• Humans
• Male
• Middle Aged
• Phosphatidylethanolamines (metabolism)
• Retina (physiopathology)
• Retinitis Pigmentosa (drug therapy, physiopathology)
• Vision Disorders (drug therapy, physiopathology)
• Visual Fields (physiology)
• Vitamin E (therapeutic use)