Objective: To assess the diagnostic utility and internal validity of the Eating Disorder Inventory (EDI-2) in Mexican women.
Material and methods: An observational, cross-sectional study was conducted between October 2000 and January 2001. The sample population consisted of two groups of women: patients diagnosed with anorexia nervosa or bulimia, but no other psychiatric pathology, seen by psychiatrists at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (National Institute of Medical Sciences and Nutrition Salvador Zubirán), and a randomly selected sample of women from a school in Mexico City. A structured interview was conducted using SCID/DSM-IV as the gold standard. Finally the EDI-2 was administered. Statistical analysis was performed using Student's t test for independent samples, Cronbach's alpha test, and calculation of sensitivity, specificity, and positive and negative predictive values.
Results: No significant differences were found for weight, height, and body mass index. Women with no eating disorders were younger than those with eating disorders (16.7 +/- 2.8 vs. 19.9 +/- 4.3, p = 0.004). The EDI-2 total score was clearly different between the groups (53.8 +/- 32.4 vs. 146.3 +/- 45.6 respectively, p < 0.001). All Cronbach's alpha coefficients for all subscales were over 0.85. For the total score, a sensitive cutoff point of 80 (sensitivity 90.9, 95% confidence interval [CI] 69.4 to 98.4; specificity 80, 95% CI 58.7 to 92.4) and a specific cutoff point of 105 (sensitivity 81.8, 95% CI 59 to 94; specificity 89.3, 95% CI 70.6 to 97.2) are recommended.
Conclusions: The EDI-2 has a high internal validity and should be a useful tool to assess eating disorders.