Generation of a Mathematical Model to Predict the Probability of Achalasia from Non-Manometric Findings
Lorenzo E. Ferri1,3, Gail Darling2, Linda Miller2, Gerald M. Fried3; 1Thoracic Surgery, McGill University, Montreal, QC, Canada; 2Thoracic Surgery, University of Toronto, Toronto, ON, Canada; 3General Surgery, McGill University, Montreal, QC, Canada
Introduction: Limited access to esophageal motility (EM) may delay achalasia patient identification and treatment. In order to assess predictors to fast-track patients for manometric confirmation of achalasia, we compared the clinical, radiographic and endoscopic characteristics of achalasia patients (AP) to non-achalasia dysphagic controls (C). Methods: Patients referred for EM to assess functional dysphagia from 2/04 to 2/05 were asked to participate in this prospective study. The Achalasia Symptom Questionnaire (ASQ), a structured 11-question survey (score:0-best,67-worst), was completed by all consenting patients. ASQ scores, esophago-gastro-duodenoscopy (EGD), upper GI contrast study (UGI) were compared between patents with subsequently confirmed achalasia (AP) and those in whom achalasia was excluded by EM (C). Data presented as mean ± SD; Univariate analysis (t-test and Chi-square) identified predictors that were tested in multivariate logistic regression to generate the model. (* p<0.05). Results: Of 803 EM performed from 2/04-2/05, 95 patients were referred specifically to rule out achalasia. 50 APs and 45 Cs were identified. ASQ scores were higher in AP (37±13 vs 23±10)*. EGD and/or UGI reports were available in 92% APs and 80% Cs. Significant predictors for achalasia with odds ratios are presented in the table. Probability of achalasia is predicted by P where P=ey/(1+e y) and y=-5.6+(0.089xASQ) +(2.088 x EGD) + (3.083xUGI), e=exponential constant 2.7182, EGD and UGI = 0 if normal and 1 if abnormal. For a given patient with ASQ >40, abnormal UGI and EGD the probability of achalasia is >96%, if ASQ <30 with normal UGI and EGD probability is less than 5% for achalasia. Conclusions: Achalasia can be accurately predicted in patients with functional dysphagia based on clinical, endoscopic, and radiographic findings allowing for a prioritization of esophageal motility.
PREDICTOR | OR | 95% CI |
ASQ>40* | 11.3 | 3.1-41.3 |
EGD-dilated esoph* | 17.1 | 4.3-67.2 |
EGD-retained food* | 12.6 | 3.2-49.1 |
EGD-tight GEJ* | 7.3 | 2.4-22.3 |
EGD-any abnorm.* | 8.3 | 2.8-24.5 |
UGI-contrast hold-up* | 10.8 | 2.8-40.2 |
UGI-dilated esoph.* | 17.2 | 3.9-74.5 |
UGI-any abnorm.* | 27.1 | 5.0-144.5 |
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