title: Rationale and design of the PREFERS (Preserved and Reduced Ejection Fraction Epidemiological Regional Study) Stockholm heart failure study: an epidemiological regional study in Stockholm county of 2.1 million inhabitants.
abstract: OBJECTIVE
  Heart failure (HF) with preserved (HFpEF) or reduced (HFrEF) ejection fraction is associated with poor prognosis and quality of life. While the incidence of HFrEF is declining and HF treatment is effective, HFpEF is increasing, with no established therapy. PREFERS Stockholm is an epidemiological study with the aim of improving clinical care and research in HF and to find new targets for drug treatment in HFpEF (https://internwebben.ki.se/sites/default/files/20150605_4d_research_appendix_final.pdf).
  
  
  METHODS
  Patients with new-onset HF (n = 2000) will be characterized at baseline and after 1-year follow-up by standardized protocols for clinical evaluation, echocardiography, and ECG. In one subset undergoing elective coronary bypass surgery (n = 100) and classified according to LV function, myocardial biopsies will be collected during surgery, and cardiac magnetic resonance (CMR) imaging will be performed at baseline and after 1 year. Blood and tissue samples will be stored in a biobank. We will characterize and compare new-onset HFpEF and HFrEF patients regarding clinical findings and cardiac imaging, genomics, proteomics, and transcriptomics from blood and cardiac biopsies, and by established biomarkers of fibrosis, inflammation, haemodynamics, haemostasis, and thrombosis. The data will be explored by state-of-the-art bioinformatics methods to investigate gene expression patterns, sequence variation, DNA methylation, and post-translational modifications, and using systems biology approaches including pathway and network analysis.
  
  
  CONCLUSIONS
  In this epidemiological HF study with biopsy studies in a subset of patients, we aim to identify new biomarkers of disease progression and to find pathophysiological mechanisms to support explorations of new treatment regimens for HFpEF.
authors.affiliation: Karolinska Institutet, Department of Medicine, Stockholm, Sweden. cecilia.linde@ki.se.|Karolinska University Hospital, Department of Cardiology, Stockholm, Sweden. cecilia.linde@ki.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Linde
authors.affiliation: Karolinska University Hospital, Department of Clinical Physiology, Stockholm, Sweden.|Karolinska Institutet, Department of Molecular Medicine and Surgery, Stockholm, Sweden.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Eriksson
authors.affiliation: Karolinska Institutet, Department of Medicine, Stockholm, Sweden.|Karolinska University Hospital, Department of Cardiology, Stockholm, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Hage
authors.affiliation: Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, Stockholm, Sweden.|Danderyd Hospital, Department of Cardiology, Stockholm, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Wallén
authors.affiliation: Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.|Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Persson
authors.affiliation: Karolinska Institutet, Department of Molecular Medicine and Surgery, Stockholm, Sweden.|Karolinska University Hospital, Department of Thoracic Surgery, Stockholm, Sweden.
authors.forename: Matthias
authors.initials: M
authors.lastname: Corbascio
authors.affiliation: Science for Life Laboratory, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Lundeberg
authors.affiliation: Karolinska University Hospital, Department of Clinical Physiology, Stockholm, Sweden.|Karolinska Institutet, Department of Molecular Medicine and Surgery, Stockholm, Sweden.
authors.forename: Eva
authors.initials: E
authors.lastname: Maret
authors.affiliation: Karolinska University Hospital, Department of Clinical Physiology, Stockholm, Sweden.|Karolinska Institutet, Department of Molecular Medicine and Surgery, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Ugander
authors.affiliation: Karolinska Institutet, Department of Clinical Sciences, Danderyd Hospital, Stockholm, Sweden.|Danderyd Hospital, Department of Cardiology, Stockholm, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Persson
mesh_terms: D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D016021:Epidemiologic Studies; D006333:Heart Failure / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D006801:Humans; D013318:Stroke Volume; D013548:Sweden / Q000453:epidemiology
chemical_list: D015415:Biomarkers
keywords: Atrial fibrillation; Bioinformatics; Biomarkers; Echocardiography; Heart failure; Prognosis