Alpha-Lipoic Acid for the Prevention of Diabetic Macular Edema

Introduction: To evaluate the effect of alpha-lipoic acid (ALA) on
the occurrence of diabetic macular edema. Methods: Randomized,
double-blind, placebo-controlled, multicenter, multinational study.
Patients were randomized to the treatment group with 600 mg ALA per
day or the placebo group. Every 6 months stereo fundus photographs,
HbA1c levels, and an ophthalmological examination were documented.
The primary endpoint was the occurrence of clinically significant
macular edema (CSME) within a follow-up period of 2 years. Results:
We randomized 235 patients with type II diabetes mellitus into the
treatment group (mean age 58.0 years) and 232 into the placebo
group (mean age 57.9 years). Mean HbA1c level was 8.1, with no
significant differences between the treatment (mean 8.2, SD +/-
1.35) and placebo groups (mean 8.1, SD +/- 1.29). HbA1c values
remained constant over time. In the treatment and placebo groups,
84 and 86 patients (35.7 and 37.1%) had insulin-dependent diabetes
mellitus (IDDM) with a median duration of diabetes of 9.3 versus
9.0 years in the placebo group. Visual acuity remained unchanged
during the entire trial. Concerning the primary endpoint, the study
provided a negative result, i.e. 26/235 patients in the treatment
group and 30/232 patients in the placebo group developed CSME.
Confirmatory intention-to-treat analysis of the primary endpoint
revealed no statistically significant difference between groups
(log-rank test, p = 0.7108, HR = 0.9057 with CI = 0.5355-1.5317).
Median follow-up was identical (2.00 years). Conclusions: A daily
dosage of 600 mg ALA does not prevent the occurrence of CSME in
IDDM patients. Copyright (C) 2011 S. Karger AG, Basel