Bidirectional Causal Association Between Chronic Obstructive Pulmonary Disease and Cardiovascular Diseases: A Mendelian Randomization Study.

Background: A large number of studies have demonstrated links between chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVDs). However, the causal relationship between COPD and CVDs and the reverse causality remains divergent. Methods: Exposure and outcome data from the largest available genome-wide association studies were extracted for Mendelian randomization (MR) studies. Univariate MR analysis was performed using IVW as the primary analysis method, and multiple sensitivity analyses were used to enhance the robustness of the results. Furthermore, this was followed by mediation MR analysis of positive results after excluding confounding factors with multivariable MR analysis. Results: The MR estimation based on IVW method indicated a strong association between genetically determined COPD and heart failure (HF) (OR = 1.117, 95% CI: 1.066-1.170, p <0.001), coronary heart disease (CHD) (OR = 1.004, 95% CI: 1.002-1.006, p <0.001), essential hypertension (EH) (OR = 1.009, 95% CI: 1.005-1.013, p <0.001) as well as Stroke (OR = 1.003, 95% CI: 1.001-1.004, p <0.001). The results of multivariable MR analysis revealed that COPD is not significantly associated with CHD after adjusting for IL-6, LDL, or total cholesterol (p>0.05). Our findings indicated that BMI, smoking initiation, smoking status, obesity, and FEV1 played a role in the causal effect of COPD on HF, EH, and Stroke. Conclusion: We found positive causal relationships between COPD and HF, EH, and Stroke essentially unaffected by other confounding factors. The causal relationship exhibited between COPD and CHD was influenced by confounding factors. BMI, obesity, initiation of smoking, smoking status, and FEV1 were the mediators between COPD and CVDs.

Non-linear Association of CAR with all-Cause and Cardiovascular Mortality in Coronary Heart Disease: A Retrospective Cohort Study from NHANES.

OBJECTIVE: To investigate the relationship between C-reactive protein and albumin ratios (CAR) and all-cause and cardiovascular disease(CVD)-specific mortality in individuals with coronary heart disease(CHD). METHODS: The data from 1895 patients were extracted from the National Health and Nutrition Examination Survey (NHANES) database from 1999-2010. We used weighted COX regression analyses to explore the association between CAR, all-cause, and CVD-specific mortality. Restricted cubic spline(RCS) regression models and threshold effects analysis were used to analyze nonlinear relationships. Subgroup analyses were also performed to explore these relationships further. RESULTS: During a mean follow-up of 115.78 months, 61.48% of deaths occurred, and 21.85% were due to CVD. After adjusting for potential confounders, each 1-unit increase in CAR was associated with a 65% increase in all-cause mortality and a 67% increase in CVD-specific mortality. The RCS model revealed a non-linear association between CAR and the risk of all-cause mortality and CVD-specific mortality in CHD patients (all non-linear P < 0.001). Threshold effects analysis identified inflection points in regression models of all-cause mortality (0.04, P < 0.001) and CVD-specific mortality (0.05, P = 0.0024). The interaction tests found sex, smoking and diabetes influenced the association between CAR and all-cause mortality and sex, smoking and HF influenced its association with CVD-specific mortality (all P < 0.05). CONCLUSION: There was a nonlinear association between CAR and all-cause mortality and CVD mortality in patients with CHD, with a higher hazard ratio before the inflection point. Sex, smoking, diabetes, and HF might have an effect on the associations between CAR and death risks.