Central-to-brachial blood pressure amplification in type 2 diabetes: a systematic review and meta-analysis

Due to systolic blood pressure (SBP) amplification, brachial SBP may not accurately reflect central SBP, the pressure the organs are exposed to. Patients with type 2 diabetes (T2D) have vascular irregularities that may affect blood pressure (BP) amplification and central BP indices (i.e. augmentation index [AIx] and augmentation pressure [AP]). By systematic review and meta-analysis, this study aimed firstly to determine the magnitude of central-to-brachial SBP and pulse pressure (PP) amplification in T2D compared to healthy controls and secondly, the difference in AIx and AP between the groups. Online databases were searched for published studies reporting invasive or non-invasive central and brachial SBP in T2D and healthy controls up to the 20th of February 2018. Random effects meta-analyses and meta-regression were used to analyze the studies. Eighteen studies (all non-invasive: 17 radial tonometry, 1 carotid tonometry, 2 brachial oscillometry) with a total of 2758 patients with T2D and 10,561 healthy controls were identified. There was no significant difference in SBP amplification between groups (T2D = 9.9 ± 4.7, healthy controls = 9.6 ± 4.5 mmHg, p = 0.84; pooled difference = 0.64 mmHg, 95%CI -0.27 1.54, p = 0.17) or PP amplification ratio (p = 0.16). However, among these studies, central BP indices (AIx corrected for heart rate and AP) were significantly higher in T2D (p < 0.05 for both). Despite a similar magnitude of central-to-brachial SBP amplification, patients with T2D have increased central systolic loading (AIx and AP) that cannot be discerned from brachial BP alone.