Reliability of the Eating Disorder Examination-Questionnaire in patients with binge eating disorder
Introduction
The Eating Disorder Examination Questionnaire (EDE-Q; Fairburn & Beglin, 1994) is the self-report version of the investigator-based Eating Disorders Examination interview (EDE; Fairburn & Cooper, 1993). Similar to the interview version, the EDE-Q provides a comprehensive assessment of eating disorder psychopathology and concomitant behaviors, but—unlike the interview—requires minimal time and resources to administer.
A growing number of studies have examined the concordance between the EDE-Q and the EDE interview, which is currently regarded as the best established method for the assessment of eating disorder psychopathology (Grilo, 1998; Wilson, 1993). The EDE-Q and EDE have been compared in diverse study groups including community samples (Fairburn & Beglin, 1994; Mond, Hay, Rodgers, Owen, & Beumont, 2004a), various eating disorder patient groups (Carter, Aime, & Mills, 2001; Grilo, Masheb, & Wilson (2001a), Grilo, Masheb, & Wilson (2001b); Loeb, Pike, Walsh, & Wilson, 1994; Sysko, Walsh, & Fairburn, in press; Wilfley, Schwartz, Spurrell, & Fairburn, 1997), and other clinical groups such as substance abusers (Black & Wilson, 1996), obese patients seeking bariatric surgery (Kalarchian, Wilson, Brolin, & Bradley, 2000), and children or adolescents (Declawue & Braet, 2004; Passi, Bryson, & Lock, 2003). Overall, most studies with adult groups have reported some areas of acceptable levels of agreement between the self-report and interview formats. In general, the agreement between the EDE-Q and EDE is quite good for certain concrete behaviors (such as vomiting), but appears to be less impressive for more complex overeating behaviors, although there is considerable discrepancy across studies (Grilo, Masheb, & Wilson (2001a), Grilo, Masheb, & Wilson (2001b); Wilfley et al., 1997) and for different patient groups (Kalarchian et al., 2000; Passi et al., 2003). Lastly, studies generally find that the EDE-Q tends to yield higher scores (albeit significantly correlated) than the EDE for the attitudinal features of eating disorders.
The EDE-Q is being increasingly used to measure treatment outcome (Carter & Fairburn, 1998; Walsh, Fairburn, Mickley, Sysko, & Parides, 2004) and in prospective epidemiological studies (Mond, Hay, Rodgers, Owen, & Beumont, 2004b). This trend likely reflects a combination of potent pragmatic issues (low cost and low burden associated with self-report) and the generally acceptable findings noted above for the EDE-Q. We emphasize here, as have others (Sysko et al., in press) that the discrepancies across the studies comparing the EDE-Q and EDE dictate the need for further psychometric investigation in this area.
In contrast to the growth of studies examining the convergence between the EDE-Q and EDE (one aspect of validity), there exists a dearth of data pertaining to the reliability of both instruments. To date, only two studies have examined the test–retest reliability of the EDE (Grilo, Masheb, Lozano-Blanco, & Barry, 2004; Rizvi, Peterson, Crow, & Agras, 2000); both reported good reliabilities for binge eating and acceptable (albeit variable) reliabilities for the four EDE subscales. To our knowledge, only one published report (Luce & Crowther, 1999) exists for the test–retest reliability of the EDE-Q. Luce and Crowther (1999) performed a short-term (2 weeks) test–retest study of the EDE-Q in a study group of 139 female undergraduates. Test–retest correlations ranged from .81 to .94 for the four EDE-Q scales, demonstrating impressive reliabilities for the attitudinal features of eating disorders. The test–retest reliability for objective bulimic episodes was .68, demonstrating lower reliability for this key behavioral feature of eating disorders. Although these findings are promising and suggest good short-term test–retest reliability, this requires examination in clinical patient groups. Thus, the aim of this study was to examine the test–retest reliability of the EDE-Q in a clinical sample of patients with binge eating disorder.
Section snippets
Participants
Participants were 86 adults who met DSM-IV (APA, 1994) criteria for BED. Participants were aged 23–59 years (, ), 79.1% were female, 82.6% were Caucasian, 66.3% were married, and 51.8% finished college. Mean body mass index (BMI: weight (kg) divided by height (m2)) was 36.9 (5.8).
Procedures and assessments
Participants were recruited by means of print advertisements for treatment studies of binge eating at a university medical school. Prescreening criteria included age 18–60, body mass index greater than
Test–retest reliability
Table 1 shows the means, standard deviations, and ranges of values for OBEs, SBEs, and OOEs as well as the four EDE-Q subscales. To account for some nonnormality in the distribution of data, test–retest reliabilities were calculated using Spearman (rho) correlation coefficients. Test–retest reliabilities were excellent for objective bulimic episodes (.84), poor for subjective bulimic episodes (.51), and unacceptable for objective overeating episodes (.39). The EDE subscales demonstrated good
Discussion
This study examined the short-term test–retest reliability of the EDE-Q in patients with BED. Our findings suggest that patients with BED report reasonably consistent responses about objective binge eating episodes and associated attitudes when administered the EDE on two separate occasions roughly (on average) 5 days apart. The EDE-Q demonstrated utility for assessing the number of binge episodes (objective bulimic episodes), whereas the test–retest reliabilities for subjective binge episodes
Acknowledgments
Research supported by grants from the National Institutes of Health (DK49587) and Donaghue Medical Research Foundation awarded to Carlos M. Grilo, Ph.D.
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