The computer and acute abdominal pain in Leeds
On 1 April 1972 the BMJ published a comparison that F. T. de Dombal's group at the University of Leeds ran from 1 January to 1 December 1971 on 304 patients with acute abdominal pain. The diagnosis to which the computer gave the highest probability matched the final one in 279 cases (91.8%); that of the most senior clinician to see the patient in 242 (79.6%).
Why it matters
Machine diagnosis was tested prospectively, in real time, at the bedside, on every patient of the unit who met the criteria, with the final diagnosis as the yardstick. The difference in error rates, 8.2% for the computer against 20.4% for the clinician in charge, is statistically significant. The authors themselves judged the system of practical value, but only in a small percentage of cases.
Criteria: abdominal pain as the presenting complaint, arising within a week, emergency admission through the receiving room, a patient able to give a history, and a diagnosis eventually made. Junior doctors scored 72.2% (house surgeon) and 77.0% (registrar); of all 858 clinicians' diagnoses 563 (65.6%) were substantiated. Among the 294 patients with diseases in the system's database the computer scored 94.9%; it classified 84 of 85 cases of appendicitis correctly; of the 137 patients it put in the non-specific abdominal pain group, 136 proved to belong there. Computer errors: 25 of 304; errors of the clinician in charge: 62; chi-squared 15.73, P = 0.0001. The system is described in a companion paper by Horrocks et al. in the same BMJ volume, which was not read. What the record does not claim: that the system was Bayesian or how many earlier patients its data came from, since the paper refers these to the companion paper; which computer it ran on. That the work rested on Ledley and Lusted's 1959 paper: the reference list has only Lusted's 1968 book.