Causal relationship between PCSK9 inhibitor and autoimmune diseases: a drug target Mendelian randomization study

In addition to decreasing the level of cholesterol, proprotein convertase subtilis kexin 9 (PCSK9) inhibitor has pleiotropic effects, including immune regulation. However, the impact of PCSK9 on autoimmune diseases is controversial. Therefore, we used drug target Mendelian randomization (MR) analysis to investigate the effect of PCSK9 inhibitor on different autoimmune diseases.

We collected single nucleotide polymorphisms (SNPs) of PCSK9 from published genome-wide association studies statistics and conducted drug target MR analysis to detect the causal relationship between PCSK9 inhibitor and the risk of autoimmune diseases. 3-Hydroxy-3-methylglutaryl-assisted enzyme A reductase (HMGCR) inhibitor, the drug target of statin, was used to compare the effect with that of PCSK9 inhibitor. With the risk of coronary heart disease as a positive control, primary outcomes included the risk of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), myasthenia gravis (MG), multiple sclerosis (MS), asthma, Crohn's disease (CD), ulcerative colitis (UC), and type 1 diabetes (T1D).

PCSK9 inhibitor significantly reduced the risk of SLE (OR [95%CI] = 0.47 [0.30 to 0.76], p = 1.74 × 10^-3) but increased the risk of asthma (OR [95%CI] = 1.15 [1.03 to 1.29], p = 1.68 × 10^-2) and CD (OR [95%CI] = 1.38 [1.05 to 1.83], p = 2.28 × 10^-2). In contrast, HMGCR inhibitor increased the risk of RA (OR [95%CI] = 1.58 [1.19 to 2.11], p = 1.67 × 10^-3), asthma (OR [95%CI] = 1.21 [1.04 to 1.40], p = 1.17 × 10^-2), and CD (OR [95%CI] = 1.60 [1.08 to 2.39], p = 2.04 × 10^-2).

PCSK9 inhibitor significantly reduced the risk of SLE but increased the risk of asthma and CD. In contrast, HMGCR inhibitor may be a risk factor for RA, asthma, and CD.