We examined whether specifically statins, of the major lipid modifiers (statins, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and ezetimibe) have pleiotropic effects on ischemic heart disease (IHD) via testosterone in men or women. As a validation, we similarly assessed whether a drug that unexpectedly likely increases IHD also operates via testosterone. Using previously published genetic instruments we conducted a sex-specific univariable and multivariable Mendelian randomization study in the UK Biobank, including 179918 men with 25410 IHD cases and 212080 women with 12511 IHD cases. Of these three lipid modifiers, only genetically mimicking the effects of statins in men affected testosterone, which partly mediated effects on IHD. Correspondingly, genetically mimicking effects of anakinra on testosterone and IHD presented a reverse pattern to that for statins. These insights may facilitate the development of new interventions for cardiovascular diseases as well as highlighting the importance of sex-specific explanations, investigations, prevention and treatment.

BackgroundMendelian randomization (MR) provides unconfounded estimates. MR is open to selection bias particularly when the underlying sample is selected on surviving the genetically instrumented exposure and other conditions that share etiology with the outcome (competing risk before recruitment). Few methods to address this bias exist.MethodsWe use directed acyclic graphs to show this selection bias can be addressed by adjusting for common causes of survival and outcome. We use multivariable MR to obtain a corrected MR estimate, specifically, the effect of statin use on ischemic stroke, because statins affect survival and stroke typically occurs later in life than ischemic heart disease so is open to competing risk.ResultsIn univariable MR the genetically instrumented effect of statin use on ischemic stroke was in a harmful direction in MEGASTROKE and the UK Biobank (odds ratio (OR) 1.33, 95% confidence interval (CI) 0.80 to 2.20). In multivariable MR adjusted for major causes of survival and ischemic stroke, (blood pressure, body mass index and smoking initiation) the effect of statin use on stroke in the UK Biobank was as expected (OR 0.81, 95% CI 0.68 to 0.98) with a Q-statistic indicating absence of genetic pleiotropy or selection bias, but not in MEGASTROKE.ConclusionMR studies concerning late onset chronic conditions with shared etiology based on samples recruited in later life need to be conceptualized within a mechanistic understanding, so as to any identify potential bias due to competing risk before recruitment, and to inform the analysis and interpretation.

Objectives: Statins appear to have pleiotropic effects. We examined whether specifically statins, of the major lipid modifiers, operate on ischemic heart disease (IHD) via testosterone. As a validation, we assessed whether a drug that unexpectedly likely increases IHD also operates via testosterone. Design: A sex-specific univariable and multivariable Mendelian randomization study Setting: A large, population-based cohort study recruited in the UK from 2006-10, the UK Biobank Participants: 179918 men with 25410 IHD cases and 212080 women with 12511 IHD cases Main Outcome measures: Testosterone and IHD Results: Of the three lipid modulations considered, statins, proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and ezetimibe, only genetically predicted statin use in men affected testosterone (-0.15 effect size testosterone per effect size lower (of low-density lipoprotein cholesterol), 95% confidence interval (CI) -0.23 to -0.06). The genetically predicted effect of statin use on IHD in specifically men was partially mediated by testosterone (odds ratio (OR) 0.55 per effect size lower (low-density lipoprotein cholesterol), 95% CI 0.38 to 0.79, compared to OR 0.73, 95% CI 0.46 to 1.11 after allowing for testosterone). The estimate for the effect of genetically predicted statin use, independent of testosterone, was very similar in women, giving overall meta-analyzed OR 0.72, 95% CI 0.57 to 0.90 per effect size lower of low-density lipoprotein cholesterol. The genetically predicted effect of anakinra use also affected testosterone (0.022 per effect size (of IL-1Ra), 95% CI 0.01 to 0.04), and increased IHD in men. Conclusions: Statins may partially operate via testosterone in men, which may contribute to sex-specific pleiotropic effects. Anakinra operating by testosterone may also explain its unexpected effects. Our findings could facilitate the development of new interventions for cardiovascular diseases as well as highlighting the importance of sex-specific investigations and possibly treatments.

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Background: New means of treating COVID-19 are urgently needed. Genetic validation of drugs can foreshadow trial results, and help prioritize investigations. We assessed whether common drugs, suggested as possible treatments for COVID-19 (tocilizumab, anakinra and statins) with established genetic proxies, are effective in COVID-19. We also included dexamethasone as a positive control exposure because the RECOVERY trial suggested benefit in severe COVID-19. Methods: We assessed, using Mendelian randomization, whether genetic proxies of tocilizumab, anakinra, statins and dexamethasone use affected risk of very severe (cases=536, non-cases=329391) or hospitalized (cases=3199, non-cases=897488) COVID-19 using a recent genome-wide association study. Results: Using rs2228145 (IL6R) to proxy effects of tocilizumab use, no association with very severe COVID-19 was found, but possibly an inverse association with hospitalized COVID-19 (odds ratio (OR) 0.83 per standardized effect of higher soluble interleukin-6r, 95% confidence interval 0.67 to 1.02). Using rs12916 (HMGCR) to proxy effects of statins use, an inverse association with very severe COVID-19 was found (OR 0.30 per standardized effect, 95% CI 0.10 to 0.89). Using rs6743376 and rs1542176 to proxy effects of anakinra use, no associations with COVID-19 were found. Dexamethasone, instrumented by cortisol, was possibly inversely associated with very severe COVID-19 (OR 0.20 per standardized effect 95% CI 0.04 to 1.04). Conclusion: Our study provides some genetic validation for the use of both tocilizumab and statins in COVID-19, but not anakinra, whilst being consistent with the findings from the RECOVERY trial about dexamethasone. Investigation of the underlying mechanisms might facilitate re-purposing and development of effective treatments.