Association between PCSK9 inhibitor with cause-specific morality amongst cancer survivors

Abstract

Abstract Background Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor has emerged as a novel pharmacotherapy for dyslipidemia and been shown to be effective in reducing the risks of atherosclerotic cardiovascular diseases. PCSK9 is aberrantly expressed in a broad spectrum of cancers and has been demonstrated to contribute to cancer prognosis. However, no prior study has investigated the associations between PCSK9 inhibitors (PCSK9i) with cardiovascular and cancer mortality amongst cancer survivors. Purpose This study investigated the effects of PCSK9i on cause-specific mortality amongst cancer survivors. Methods This retrospective study used data from the Tianjin Coronary Artery Disease Cohort, which included medical data from 71 secondary or tertiary hospitals in Tianjin, China. Adult patients with coronary artery disease (CAD) diagnosed with incident cancer between 2017 and 2023 were enrolled in this study. Propensity score matching with a 1:3 ratio for PCSK9i users versus non-users was performed. The primary outcomes included all-cause mortality, cardiovascular mortality, and cancer mortality. Multivariable Cox regression was used to test associations between PCSK9i with outcomes, adjusting for age, gender, cardiovascular and non-cardiovascular comorbidities, lipid-lowing agents and other medication use, lipid level, as well as cancer characteristics. Multivariable competing risk analysis was used as sensitivity analysis. Results A total of 62,341 incident cancer patients were identified. After matching, 424 PCSK9i users and 1,272 non-users were included in this study. During a median follow-up of 1,009 days, 315 patients died, among which 98 died due to cardiovascular cause, 146 died due to cancer cause. Compared to non-users, cancer patients treated with PCSK9i presented with significantly lower risk of all-cause mortality (hazard ratio [HR], 0.33; 95% confidence interval [CI] 0.23-0.47; p <0.001), after adjusting for potential confounders. In addition, PCSK9i therapy was associated with a 63% lower risk of cardiovascular mortality (HR, 0.37; 95%CI 0.20-0.69; p=0.002) and a 75% lower risk of cancer-related mortality (HR, 0.25; 95%CI 0.14-0.45; p<0.001), in relation to non-PCSK9i group. Sensitivity analysis using multivariable competing risk model also suggested a significant association between PCSK9i treatment with reduced risk of cardiovascular mortality (HR, 0.41; 95%CI 0.22-0.76; p=0.005) and cancer mortality (HR, 0.26; 95%CI 0.15-0.48; p<0.001) among cancer survivors. Conclusion The use of PCSK9i was associated lower risks of all-cause, cardiovascular-related, and cancer-related mortality amongst cancer survivors. These findings potentially indicate benefits of PCSK9i beyond adverse cardiovascular events related to atherosclerosis.