The associations of stroke, transient ischemic attack, and/or stroke-related recurrent vascular events with Lipoprotein-associated phospholipase A(2): A systematic review and meta-analysis

BACKGROUND: Studies on stroke and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) have produced conflicting results. OBJECTIVE: The aim of the study was to assess the associations of Lp-PLA(2) levels (mass and activity) with recurrent vascular events in patients with transient ischemic attack (TIA) and/or first ischemic stroke and with stroke in the general population. METHODS: The MEDLINE, Embase, the Cochrane Library, Web of Science, Science Direct, China National Knowledge Infrastructure, China Biology Medical Disc (CBMdisc), and WanFang were searched for prospective observational studies reported until January 2017. Eligible studies reported Lp-PLA2 levels and adjusted risk estimates of recurrent vascular events and/or stroke. Risk ratio (RR) with corresponding 95% confidence intervals (CIs) were used to express the pooled data in a random-effects model. RESULTS: A total of 11 studies that comprised 20,284 participants (4,045 were TIA and/or first ischemic stroke patients and 16,239 were residents in general population) were identified, which reported either Lp-PLA(2) mass levels (4 studies) or Lp-PLA(2) activity levels (10 studies). The pooled RR of recurrent vascular events (467 cases) in TIA and/or first ischemic group was 2.24 (95% CI, 1.33–3.78), whereas the pooled RR of stroke (1604 cases) in the general population was 1.47 (95% CI, 1.10–1.97). The pooled RRs of Lp-PLA(2) mass and activity levels with the risk of stroke in the general population were 1.69 (95% CI, 1.03–2.79) and 1.28 (95% CI, 0.88–1.85), respectively. CONCLUSIONS: In patients with TIA and first ischemic stroke, elevated Lp-PLA2 activity levels were associated with recurrent vascular events. And in the general population elevated Lp-PLA2 levels were associated with the risk of stroke, although the association between Lp-PLA(2) activity levels and the risk of stroke was less profound compared with the corresponding association of stroke risk with the Lp-PLA(2) mass levels.