title: An analysis of serial Minnesota ECG code changes in the London cohort of the WHO Multinational Study of Vascular Disease in Diabetes.
abstract: OBJECTIVE
  Deterioration and improvement in the electrocardiogram are important outcomes in cardiovascular disease progression assessment. We used a sample of serial records from the WHO Multinational Study of Vascular Disease in Diabetes (WHO MSVDD) to assess Minnesota coding variability.
  
  
  METHODS
  A constructed subsample of 118 of the 352 paired (baseline and follow-up) and previously Minnesota-coded ECG records from the London cohort was randomised and re-read independently of the first code (respectively 11 and 0.5 years later) by the same two coders. Detailed Minnesota codes were summary coded into groups 1 (CHD unlikely), 2 and 3 (CHD possible and probable, respectively).
  
  
  RESULTS
  Re-reading of the constructed sample for the baseline records (11 years later) generated 21 Summary code reassignments (2 unlikely to possible or probable; 19 possible or probable to unlikely); re-reading for the follow-up records (0.5 years later) generated only 8 summary code reassignments (21 vs 8p < 0.001) (3 unlikely to possible or probable; 4 possible or probable to unlikely; 1 probable to possible). Re-reading increased the estimated net ECG deterioration in the constructed sample from 11.8 % to 25.4%. Consistency analysis showed most variability in marginal baseline abnormalities.
  
  
  CONCLUSIONS
  Coding variability is now small though re-reading suggests some time-dependent coding drift. Relative over-reading at baseline suggests that the change reported in the complete WHO MSVDD cohort at follow-up was underestimated and that almost all of the reported ECG deterioration and about half of the reported ECG 'improvement' was real.
authors.affiliation: Unit for Metabolic Medicine, Guy's Hospital, London, UK.
authors.forename: H
authors.initials: H
authors.lastname: Keen
authors.forename: N
authors.initials: N
authors.lastname: Morrish
authors.forename: E T
authors.initials: ET
authors.lastname: Lee
mesh_terms: D002318:Cardiovascular Diseases / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000453:epidemiology / Q000503:physiopathology*; D004562:Electrocardiography / Q000145:classification*; D006801:Humans; D007391:International Cooperation; D008131:London / Q000453:epidemiology; D008910:Minnesota; D014944:World Health Organization