The use of administrative health data is increasingly common for the study of various medical and surgical diseases.
The validity of diagnosis codes for the study of benign upper gastrointestinal disorders has not been well studied.
Dr Lopushinsky and colleagues from Canada abstracted the charts for 590 adult patients who underwent upper gastrointestinal endoscopy between 2000 and 2001 in Toronto, Canada.
Clinical diagnoses from medical records were compared with International Classification of Diseases Version 9 codes in electronic hospital discharge abstracts.
The team determined the sensitivity, specificity, and positive predictive value of a most responsible ‘esophagitis' diagnosis code for the prediction of esophagitis.
|81% of patients had home internet access|
Secondary analyses determined the performance characteristics of the diagnostic codes for esophageal ulcer, esophageal stricture, gastroesophageal reflux disease (GERD), gastritis, gastric ulcer, and duodenal ulcer.
The researchers linked 500 patient records to electronic discharge abstracts.
When listed as the most responsible diagnosis for admission, the ICD-9 codes for esophagitis showed a sensitivity of 47%, a specificity of 99%.
The research team found that the positive predictive value was 95%.
The team noted that, when listed as a secondary diagnosis, the ICD-9 codes showed a sensitivity of 71%, a specificity of 98%, and a positive predictive value of 93%.
The diagnostic properties of ICD-9 codes for GERD were as follows: sensitivity (56%, 79%), specificity (99%, 97%), and positive predictive value (95%, 92%).
Dr Lopushinsky's team concluded, "The ICD-9 diagnosis codes for benign upper gastrointestinal diseases are highly specific and associated with strong positive predictive values, but have poor sensitivity."