Impact of PCSK9 loss-of-function genotype on 1-year mortality and recurrent infection in sepsis survivors

Background: Reduced activity of proprotein convertase subtilisin/kexin type 9 (PCSK9) has been associated with decreased short-term death in patients with septic shock. Whether PCSK9 genotype influences long-term outcomes in sepsis survivors is unknown. Methods: We evaluated the impact of PCSK9 loss-of-function (LOF) genotype on both 1-year mortality and infection-related readmission (IRR) after an index sepsis admission. The Derivation cohort included 342 patients who survived 28 days after a sepsis admission in a tertiary hospital (Vancouver/Canada, 2004-2014), while an independent Validation cohort included 1079 septic shock patients admitted at the same hospital (2000-2006). All patients were genotyped for three common missense PCSK9 LOF variants rs11591147, rs11583680, rs562556 and were classified in 3 groups: Wildtype, single PCSK9 LOF, and multiple PCSK9 LOF, according to the number of LOF alleles per patient. We also performed a meta-analysis using both cohorts to investigate the effects of PCSK9 genotype on 90-day survival. Findings: In the Derivation cohort, patients carrying multiple PCSK9 LOF alleles showed lower risk for the composite outcome 1-year death or IRR (HR: 0.40, P=0.006), accelerated reduction on neutrophil counts (P=0.010), and decreased levels of PCSK9 (P = 0.037) compared with WT/single LOF groups. Our meta-analysis revealed that the presence of multiple LOF alleles was associated with lower 90-day mortality risk (OR=0.69, P= 0.020). Interpretation: The presence of multiple PCSK9 LOF alleles decreased the risk of 1-year death or IRR in sepsis survivors. Biological measures suggest this may be related to an enhanced resolution of the initial infection. Funding: Canadian Institutes of Health Research (PJT-156056). (c) 2018 The Authors. Published by Elsevier B.V.