title: Positive predictive value of cardiac examination, procedure and surgery codes in the Danish National Patient Registry: a population-based validation study.
abstract: Danish medical registries are widely used for cardiovascular research, but little is known about the data quality of cardiac interventions. We computed positive predictive values (PPVs) of codes for cardiac examinations, procedures and surgeries registered in the Danish National Patient Registry during 2010-2012.
  
  
  
  Population-based validation study.
  
  
  
  We randomly sampled patients from 1 university hospital and 2 regional hospitals in the Central Denmark Region.
  
  
  
  1239 patients undergoing different cardiac interventions.
  
  
  
  PPVs with medical record review as reference standard.
  
  
  
  A total of 1233 medical records (99% of the total sample) were available for review. PPVs ranged from 83% to 100%. For examinations, the PPV was overall 98%, reflecting PPVs of 97% for echocardiography, 97% for right heart catheterisation and 100% for coronary angiogram. For procedures, the PPV was 98% overall, with PPVs of 98% for thrombolysis, 92% for cardioversion, 100% for radiofrequency ablation, 98% for percutaneous coronary intervention, and 100% for both cardiac pacemakers and implantable cardiac defibrillators. For cardiac surgery, the overall PPVs was 99%, encompassing PPVs of 100% for mitral valve surgery, 99% for aortic valve surgery, 98% for coronary artery bypass graft surgery, and 100% for heart transplantation. The accuracy of coding was consistent within age, sex, and calendar year categories, and the agreement between independent reviewers was high (99%).
  
  
  
  Cardiac examinations, procedures and surgeries have high PPVs in the Danish National Patient Registry.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.|Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Adelborg
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.|Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Sundbøll
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Troels
authors.initials: T
authors.lastname: Munch
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Trine
authors.initials: T
authors.lastname: Frøslev
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
authors.affiliation: Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.|Department of Internal Medicine, Randers Regional Hospital, Randers, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Schmidt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006348:Cardiac Surgical Procedures / Q000145:classification; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000601:surgery / Q000628:therapy; D059019:Clinical Coding / Q000592:standards*; D003718:Denmark; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012042:Registries