L-shaped association between ankle-brachial index and coronary heart disease in Chinese adults with hypertension

Purpose: Previous studies have shown that ankle-brachial index (ABI) ≤ 0.9 is independently and positively correlated with cardiovascular events, including coronary heart disease (CHD), However, ABI, as a classified variable, has limited effect in exploring the relationship between CHD. We aimed to investigate the association of ABI level with CHD in hypertensive population. Methods This cross-sectional analysis based on the registration study of H-type hypertension in China included 10,900 hypertensive patients. Multivariable linear regression and multivariable binary logistic regression analyses were conducted to assess the associations between WWI and MMSE and dementia, respectively. Results The study participants had a mean (SD) age of 68.3 (9.25) years and 5129 (47.06%) were men. The outcome was CHD. There were 552 (5.06%) participants who had CHD in10900 hypertensive participants. Overall, there was an L-shaped association of ABI with CHD. The full adjusted OR of CHD for participant's ABI level were 0.75 (95%CI: 0.33–1.71). Association of ABI with CHD was evaluated binary logistic regression model, which figured out the turning point was 1.07. On the left of the turning point, ABI is negatively correlated with CHD (OR: 0.27; 95%CI:0.08–0.84), while the prevalence of CHD does not decrease with the increase of ABI level on the right of turning point (OR: 3.08; 95%CI:0.60–15.80). Conclusion The results of stratified analysis showed that ABI and CHD were L-shaped related. In this large-scale cross-sectional study, ABI has a nonlinear L-shaped association with CHD in Chinese adult with high blood pressure and its inflection point was 1.07.