Serum Malondialdehyde Levels in Hypertensive Patients: A Non-invasive Marker of Oxidative Stress. A Systematic Review and Meta-analysis.

Abstract

Previous analyses have reported a higher malondialdehyde (MDA) serum level in hypertensive patients (HTs) compared to normotensive subjects (NTs). We performed a systematic review and meta-analysis of these studies to offer a comprehensive information on this issue. The PubMed, EMBASE and Web of Science databases were analysed to locate English-language articles published from January 1, 2000 up to January 1 2021. Studies were identified using the following MeSH terms: "Malondialdehyde" AND "Arterial hypertension". The difference of MDA serum levels between HTs and NTs was expressed as standardized mean difference (SMD) with 95% CI using a random-effect model. A total of of 4102 patients (2158 HTs and 1944 NTs, mean age 52.7 and 48.0 years, respectively) were included in 17 studies. Pooled mean MDA serum levels in HTs and NTs were 4.91 [standard error (SE): 0.34, 95% CI 4.23-5.59)] and 3.43 [SE 0.15, 95% CI 3.18-3.78] nmol/L, respectively. The SMD between HTs and NTs was 3.23 nmol/L (95% CI 2.54-3.92; Z-score for overall effect: 9.17, p<0.0001, I2=98.6%). Egger's test resulted significant at p = 0.009 while Begg's test was not, p = 0.11. Subsequent adjustment via the trim-and-fill method did not predict a new model (studies trimmed=0). Meta-regression analysis found no correlations either between SMD and age (p=0.95) or BMI (p=0.96) but a significant one considering the latitude of the study site as moderator variable (p=0.001). Among patients with HTs, serum MDA appears to have the greatest potential as non-invasive biomarkers of oxidative stress and endothelial dysfunction (ED).