The Diagnostic Value of Scoring Models for Organic and Non-organic Gastrointestinal Disease, Including the Irritable-bowel Syndrome

Scoring models based on history and physical examination have been developed to dis criminate patients with non-organic gastrointestinal disease from those who have organic disease. The application of these models may lead to more efficient diagnosis and prevent somatization. Although the models have high diagnostic accuracy in the population in which they have been developed, their value in other populations has not been established. In this study previously developed models were tested in validation populations defined by the original selection criteria from the studies in which the models were developed and in un selected general practice and outpatient populations. The diagnostic performances of the models are expressed in terms of odds ratio and sensitivity and specificity for the classification of patients as having organic and non-organic disease. The diagnostic performances of all the models were rather low in the validation populations. Relatively few elements of the models had independent diagnostic value. In addition, the correlation between the scoring models, expressed in Cohen's kappa, was extremely low. The diagnostic values of the scoring models were not reproduced in comparable and unselected populations. Therefore, it is concluded that the diagnostic value of such a model has little external validity. Key words: scoring models; gastrointestinal disease; validation; diagnosis; predictive validity. (Med Decis Making 1994;14:208—216)