Cardiovascular disease (CVD) is the leading cause of death globally, and diabetes mellitus (DM) is increasingly prevalent worldwide. People with DM are at a higher risk of developing heart-related complications that can lead to serious health issues and death. Chest pain (CP) and shortness of breath (SOB) are common manifestations of cardiopulmonary disorders. These symptoms often prompt people to seek emergency medical care.

Risk stratification involves assessing a patient's probability of experiencing complications and premature death. Determining the necessary interventions to improve the patients' health outcomes is essential. Healthcare professionals encounter daily challenges in risk stratification. Identifying new and clinically relevant markers for improved risk stratification is crucial.

This thesis aims to assess whether blood biomarkers could predict the risk of adverse events and prognosis in emergency care patients with CP and/or SOB. Additionally, this work evaluates risk markers for identifying patients with higher risk of CVD and premature death in type 2 diabetes (T2DM) patients.

Papers I and II assessed the predictive values of copeptin, mid-regional pro-adrenomedullin (MRproADM), and mid-regional pro-atrial natriuretic peptide (MRproANP) as potential markers for risk stratification in emergency departments (ED). These studies were based on the ABBA population, a single-center observational study conducted at the Linköping Hospital ED.

In Paper I, age, sex, oxygen saturation, heart rate, National Early Warning Score (NEWS) category, and copeptin were found to be associated with admission to a hospital ward from the ED. Copeptin was found to have an added predictive value for admission compared to NEWS alone.

In Paper II, MRproADM levels >0.75 nmol/L and multimorbidity were significantly associated with readmission and/or death within 90 days. MRproADM improved the predictive value of readmission and/or death within 90 days compared to age, sex, and multimorbidity combined. 

Papers III, IV, and V were based on CARDIPP, a research program aimed at identifying markers for CVD in T2DM patients. This population-based study involved primary care patients aged 55−65, with a baseline survey conducted between 2005 and 2008. The cohort was monitored for CVD morbidity and mortality from a national registry.

In Paper III, patients with T2DM and low toe brachial index (TBI) had an increased risk of major adverse cardiovascular events (MACE) independent of arterial stiffness.

In Paper IV, we found that an increasing copeptin level was significantly associated with MACE. Patients with copeptin levels ≥5.6 pmol/L had an unfavorable risk for MACE, independent of traditional CVD risk factors and left ventricular mass index.

Paper V found that copeptin was associated with TBI and aortic pulse wave velocity (aPWV), both markers of arterial disorders, independent of traditional CVD risk factors.

In conclusion, early analysis of copeptin may be helpful for patient risk assessments. MRproADM and multimorbidity may predict the risk of readmission and/or death within 90 days. In patients with T2DM, low TBI, and elevated copeptin levels may serve as important indicators for increased risk of MACE. Copeptin may be a helpful surrogate for identifying individuals at higher risk of arterial disorders.