Abstract 14875: Reporting Quality of Studies Measuring Endothelial Dysfunction in Diet Intervention Studies
Vascular endothelial dysfunction (EF), most often measured by flow mediated dilation (FMD), has been studied as a surrogate marker for atherosclerosis and as an indicator of vascular health and reactivity. However, this measurement is subject to technical challenges and other factors including investigator experience; hence the need for detailed journal reporting.
Methods: A systematic PubMed search was conducted from January 2000 to August 2012 employing key words for vascular EF measures, vitamins, trace elements, fatty acids and botanicals. A total of 1218 clinical trials were identified; 207 met review inclusion criteria. Seventy RCTs with defined dietary ingredients (DI) (folic acid, omega-3 fatty acids, cocoa, and isoflavones) and standardized vascular dependent measures of EF were evaluated. Jadad scores and quality scoring parameters for DI were recorded. Quality scoring parameters for FMD methodology were developed according to guidelines (Corretti, 2000).
Results: FMD was used as the primary outcome measure in 57 of the 70 papers (81%) with no consensus of referenced method. A positive FMD outcome was reported in 61% of the papers (93% for cocoa interventions, followed by 62% for omega 3-fatty acids, 47% for isoflavones, and 45% for folic acid. Mean Corretti methodology scores (out of 12 possible points) were 7.27 ± 1.85, 7.46 ± 2.85, 6.29 ± 2.27, and 7.11 ± 2.45 for folic acid, omega-3, cocoa and isoflavones, respectively (NS). Over 90% of EF studies failed to adequately describe the equipment utilized to measure FMD and more than half of the studies failed to provide adequate description of vascular image acquisition and measurement. Lastly, one-third of the studies did not have adequate sample size for determination of the primary outcome measure of FMD. Non-cross over EF studies, independent of the DI, demonstrated higher Jadad scores compared to cross-over studies (3.86 ± 0.83 vs. 3.21 ± 1.13; p=0.017).
Conclusions: FMD can be utilized for dietary studies with serial measurements of short or long-term durations. However, future studies using the technique need to be standardized using the guidelines for assessment for both DI and FMD to increase accuracy and minimize all the potential variables.
- © 2013 by American Heart Association, Inc.