Genetic Variation in Blood Pressure and Lifetime Risk of Peripheral Artery Disease: A Mendelian Randomization Study

Abstract

Aims: We aimed to estimate the effect of blood pressure and blood pressure lowering medications (via genetic proxies) on peripheral artery disease. Methods and Results: GWAS summary statistics were obtained for BP (International Consortium for Blood Pressure + UK Biobank GWAS; N = up to 757,601 individuals), peripheral artery disease (PAD; VA Million Veteran Program; N = 24,009 cases, 150,983 controls), and coronary artery disease (CAD; CARDIoGRAMplusC4D 1000 Genomes; N = 60,801 cases, 123,504 controls). Genetic correlations between systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP) and CAD and PAD were estimated using LD score regression. The strongest correlation was between SBP and CAD (rg = 0.36; p = 3.9 x 10-18). Causal effects were estimated by two-sample MR using a range of pleiotropy-robust methods. Increased SBP, DBP, and PP increased risk of both PAD (SBP OR 1.25 [1.19-1.31] per 10mmHg increase, p = 3 x 10-18; DBP OR 1.27 [1.17-1.39], p = 4 x 10-8; PP OR 1.51 [1.38-1.64], p = 1 x 10-20) and CAD (SBP OR 1.37 [1.29-1.45], p = 2 x 10-24; DBP OR 1.6 [1.45-1.76], p = 7 x 10-22; PP OR 1.56 [1.4-1.75], p = 1 x 10-15). The effects of SBP and DBP were greater for CAD than PAD (pdiff = 0.024 for SBP, pdiff = 4.9 x 10-4 for DBP). Increased liability to PAD increased PP (beta = 1.04 [0.62-1.45] mmHg per 1 unit increase in log-odds in liability to PAD, p = 1 x 10-6). MR was also used to estimate the effect of BP lowering through different classes of antihypertensive medications using genetic instruments containing BP-trait associated variants located within genes encoding protein targets of each medication. SBP lowering via calcium channel blocker-associated variants was protective of CAD (OR 0.38 per 10mmHg decrease in SBP; 95% CI 0.19-0.77; p = 0.007). Conclusions: Higher BP is likely to cause both PAD and CAD but may have a larger effect on CAD risk. BP-lowering through calcium-channel blockers (as proxied by genetic variants) decreased risk of CAD.