Risk Factors for myocardial infarction in patients with peripheral artery disease

Background Peripheral artery disease (PAD) is a worldwide major health problem characterized by a reduced blood flow in the arteries of the lower limbs due to obstructive ather-osclerosis. More than 200 million people suffer from PAD worldwide, and the incidence is still in-creasing. Pathophysiologically, the underlying atherosclerosis of PAD is shared with coronary artery disease and cerebrovascular disease. PAD is afflicted by a high risk for adverse events of the limbs, but also by cardiovascular events such as myocardial infarction (MI). Clinical trials including patients with symptomatic PAD revealed a co-prevalence of known symptomatic coronary artery disease of approximately 30% and a co-prevalence regarding history of MI of 10-20%. Although the risk for MI in PAD patients is high and PAD patients are burdened by high mortality from cardiovascular causes the ability to predict MI is rather limited. Purpose We aimed to identify risk factors for MI in PAD patients, since MI is one of the most critical events during hospitalization due to PAD and an important determining factor for survival of (hospitalized) PAD patients (source: RDC of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2005-2020, own calculations). Methods The German nationwide inpatient statistics was used for this study. All patient-cases of patients admitted due PAD in Germany 2005-2020 were included and stratified for occurrence of MI. Results Overall, 2,825,765 patient-cases of patients admitted due to PAD were included in our study 2005-2020. Among these, 24,072 PAD patients (0.9%) were afflicted by MI. PAD patients with MI were older (proportion of patients aged ≥70 years: 69.6% vs. 54.2%, P<0.001) and revealed an aggravated comorbidity profile. In-hospital case-fatality rate was more than 10-fold increased driven by MI (29.0% vs. 2.7%, P<0.001). Age ≥70years (OR 1.193 [95%CI 1.158-1.229], P<0.001), diabetes mellitus (OR 1.405 [95%CI 1.369-1.442], P<0.001), hyperlipidaemia (OR 1.099 [95%CI 1.069-1.129], P<0.001), COPD (OR 1.105 [95%CI 1.064-1.148], P<0.001), kidney disease (OR 1.857 [95%CI 1.806-1.910], P<0.001), heart failure (OR 4.907 [95%CI 4.769-5.048], P<0.001), atrial fibrillation/flutter (OR 1.177 [95%CI 1.142-1.213], P<0.001), cancer (OR 1.343 [95%CI 1.242-1.451], P<0.001) and pneumonia (OR 5.214 [95%CI 5.021-5.414], P<0.001) were independently associated with MI. Conclusions MI occurred in 0.9% of the PAD patients and was afflicted by more than 10-fold increased case-fatality. Independent risk factors for MI events in patients admitted due to PAD comprised age ≥70 years, diabetes mellitus, hyperlipidaemia, lung diseases, and cancer.