title: Do discharge codes underestimate hospitalisation due to heart failure? Validation study of hospital discharge coding for heart failure.
abstract: BACKGROUND
  Discharge codes are frequently used to describe hospital activity related to heart failure (HF).
  
  
  OBJECTIVE
  To determine whether discharge codes for HF underestimated or overestimated hospital activity related to HF.
  
  
  METHODS
  Patients with atrial fibrillation (AF), who commonly have HF, were identified and their case notes reviewed to identify cases of HF missed by discharge codes.
  
  
  METHODS
  Patients admitted between November 1997 and January 1998 with either HF or AF. Identification of HF and AF by ICD10 hospital discharge codes. Identification of additional cases of AF from a central hospital-wide ECG database.
  
  
  RESULTS
  We identified 330 cases with an ICD 10 code for HF, of which 43 (13%) were deemed to be miscoded, 32 patients (10%) were classified as possible, 39 (12%) as probable and 216 (65%) as definite HF. Results were similar whether or not HF was the primary discharge diagnosis. We identified 452 patients with AF, of whom 45 (10%) were classified as probable and 193 (43%) as definite HF. 129 (54%) of these cases had no diagnostic discharge code for HF. ICD 10 discharge codes for HF were correct in 77% of cases but identified only 66% of patients with probable or definite HF in this analysis. Screening of other diagnoses would have identified further cases of HF.
  
  
  CONCLUSIONS
  Hospital discharge codes substantially underestimate hospital events related to HF in the UK.
authors.affiliation: Department of Cardiology, Glasgow Royal Infirmary, University of Glasgow, UK.
authors.forename: Aleem U
authors.initials: AU
authors.lastname: Khand
authors.forename: Morag
authors.initials: M
authors.lastname: Shaw
authors.forename: Islay
authors.initials: I
authors.lastname: Gemmel
authors.forename: John G F
authors.initials: JG
authors.lastname: Cleland
mesh_terms: D000368:Aged; D005260:Female; D005568:Forms and Records Control; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D006801:Humans; D008297:Male; D010351:Patient Discharge; D012189:Retrospective Studies; D012621:Seasons; D006113:United Kingdom / Q000453:epidemiology; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis