Combined effect of heart disease and high CRP levels on new-onset stroke in middle-aged and older Chinese adults: a prospective cohort study from CHARLS

Abstract Background This study aimed to investigate whether the coexistence of heart disease and high C-reactive protein (CRP) levels increases the risk of new-onset stroke among middle-aged and elderly Chinese individuals. Methods The analysis incluCombined Effect of Heart Disease and high CRP levels on New-Onset Stroke in Middle-Aged and Older Chinese Adults: A Prospective Cohort Study from CHARLSded 7,995 Chinese participants aged 45 years or older from the China Health and Retirement Longitudinal Study (CHARLS). Multivariable Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of new-onset stroke according to heart disease and CRP levels. In addition, incremental predictive values were also assessed using the net reclassification index (NRI), and integrated discrimination improvement (IDI). Results Compared with participants free of both conditions, multivariable-adjusted models showed that new-onset stroke risk did not increase significantly in those with heart disease alone (HR = 1.17, 95% CI: 0.93–1.48) or high CRP levels alone (HR = 1.19, 95% CI: 0.96–1.49). In contrast, participants with both heart disease and high CRP levels showed a 58% increased risk of new-onset stroke (HR, 1.58; 95% CI , 1.11–2.26), demonstrating a significant independent association ( P value = 0.008). This combined association was further modified among participants aged < 65 years (HR = 1.20, 95% CI : 1.07–1.34), with systolic blood pressure ≥ 140 mmHg (HR = 1.21, 95% CI : 1.05–1.39), and fasting glucose ≥ 6.1 mmol/L at baseline (HR = 1.20, 95% CI : 1.03–1.40). Conclusion The coexistence of heart disease and high CRP levels significantly increases the risk of new-onset stroke, serving as potential predictors for new-onset stroke.