Meta-Analysis of Plasma PCSK9 Levels

We searched MEDLINE between January 1, 1998, and May 2015. The reference lists of retrieved articles and review articles were read manually to augment our search. The search criteria included the terms ‘PCSK9’ and ‘Proprotein convertase subtilisin/kexin type 9’. One author (J.A.R.) performed the electronic search and listed the studies that were eligible for inclusion in the study. Candidate abstracts were then reviewed and selected for data retrieval. Two authors (J.A.R. and J.H.B.) independently reviewed each study for quality assessment and extracted data on studies and patient characteristics, as well as outcomes, using standardized extraction forms. The studies were assessed for the presence of 2 features: description of the patient sample characteristics and description of the inclusion and exclusion criteria, including statin or fibrate use. Disagreements were resolved through discussion. For each study, the following individual data were extracted: general data (study design), patients (number of included patients, mean age, gender) and PCSK9 plasma levels prior to any intervention (baseline in interventional studies). In our initial search, 26 studies were found and we limited the analysis to those with subjects aged at least 18 years and acute medical process or intervention without a ‘baseline’ plasma draw. This eliminated 11 studies, leaving 15 for analysis [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22]. Pooled medians were reported with 95% confidence intervals.