Diagnosis Scenario

You have been approached by the local University Health Service. They have become very concerned about the numbers of students who present to the clinic with eating disorders during the first term of their courses. One of their main concerns is that the students present after they have already got behind in their course work.

This is a shame, because the health service has invested in lots of self-help materials and also has a whole team of trained cognitive-behavioural therapists waiting to treat eating disorders! They wonder if you have any suggestions about how they could screen their students to try and pick up cases earlier.

You form the clinical question: in female students, are there any screening tests that reliably pick up those students that have eating disorders?

You look through your issues of Evidence-Based Mental Health and find an abstract that appears helpful. You track down the full article (Journal of Counseling Psychology 44 63-79.)

Read the article and decide:

  • Are the results of this diagnostic article valid?
  • Are the valid results of this diagnostic study important?
  • Can you apply this valid, important evidence about a diagnostic test in caring for your patient?

Completed Diagnosis Worksheet for Evidence-Based Mental Health

Citation

Mintz et al Questionnaire for eating disorder: reliability and validity of operationalising DSM-IV criteria into a self-report format Journal of Counseling Psychology 44 63-79.

Are the results of this diagnostic study valid?

Was there an independent, blind comparison with a reference (“gold”) standard of diagnosis?
Yes – DSM-IV criteria for eating disorder made by structured clinical interview
Was the diagnostic test evaluated in an appropriate spectrum of patients (like those in whom it would be used in practice)?
Yes
Was the reference standard applied regardless of the diagnostic test result?
Yes

Are the valid results of this diagnostic study important?

Questionnaire for Eating Disorder Diagnoses (Q-EDD) Eating disorder No eating disorder Likelihood Ratio
Positive 32 2 50
Negative 1 101 0.03
Totals 33 103
  • For pre-test probabilities in the 20-50% range, a positive test yields post-test probabilities of 94-98% (in the latter case, a SpPin1).
  • For pre-test probabilities in the 20-50% range, a negative test yields post-test probabilities of <1% (in the latter case, a SnNout2).
  • So it can give quite useful results.

Can you apply this valid, important evidence about a screening test in helping students with eating disorders?

Do these results apply to your patient?
Is the diagnostic test available, affordable, accurate, and precise in your setting?
Needs to be assessed in each setting.
Can you generate a clinically sensible estimate of your patient’s pre-test probability (from practice data, from personal experience, from the report itself, or from clinical speculation)
Approximately 30%.
Will the resulting post-test probabilities affect your management and help your patient? (Could it move you across a test-treatment threshold?; Would your patient be a willing partner in carrying it out?)
If a student screens as positive, it would be worth offering a follow-up appointment.
Would the consequences of the test help your patient?
Probably. There are highly effective treatments (cognitive therapy, interpersonal psychotherapy) available for the most common eating disorders such as bulimia.

Additional Notes

Eating disorders: Q-EDD is a useful diagnostic tool in female college students

Clinical Bottom Line

The Q-EDD may be a useful screening instrument for eating disorders in high risk populations. It may also be a useful diagnostic tool in clinical populations

Citation

Mintz et al Questionnaire for eating disorder: reliability and validity of operationalising DSM-IV criteria into a self-report format Journal of Counseling Psychology 44 63-79.

Clinical Question

In female college students, are there any screening tests that reliably detect those students that have eating disorders?

Search Terms

Search of Evidence-Based Mental Health using web-based index

The Study

  • Gold Standard – DSM-IV criteria for eating disorder following structured clinical interview
  • Study setting – Large mid-Western public university in the USA. Participants were 136 women. 11 female counselling psychology graduate students conducted the clinical interviews.

The Evidence

Questionnaire for Eating Disorder Diagnoses (Q-EDD) Eating disorder No eating disorder Likelihood Ratio
Positive 32 2 50
Negative 1 101 0.03
Totals 33 103

Comments

Positive test can SpPin, negative test can SnNout.

Appraised By

Geddes, 1998, Reviewed 1999

Expiry Date

2000


  1. When a diagnostic test has a very high Specificity, a Positive result Rules-In the diagnosis. 
  2. When a diagnostic test has a very high Sensitivity, a Negative result Rules-Out the diagnosis.