The criterion validity of the web-based Major Depression Inventory when used on clinical suspicion of depression in primary care

Abstract

Background

The Major Depression Inventory (MDI) is widely used in Danish general practice as a screening tool to assess depression in symptomatic patients. Nevertheless, no validation studies of the MDI have been performed. The aim of this study was to validate the web-based version of the MDI against a fully structured telephone interview in a population selected on clinical suspicion of depression (ie, presence of two or three core symptoms of depression) in general practice.

Materials and methods

General practitioners (GPs) invited consecutive persons suspected of depression to complete the web-based MDI in a primary care setting. The validation was based on the Munich-Composite International Diagnostic Interview (M-CIDI) by phone. GPs in the 22 practices in our study included 132 persons suspected of depression. Depression was rated as yes/no according to the MDI and M-CIDI. Sensitivity, specificity, and positive predictive value of the International Classification of Diseases, Tenth Revision (ICD-10) algorithms of the MDI were examined.

Results

According to the M-CIDI interview, 87.9% of the included population was depressed and 64.4% was severely depressed. According to the MDI scale, 59.1% of the population was depressed and 31.8% was severely depressed. The sensitivity of the MDI for depression was 62.1% (95% confidence interval [95% CI]: 52.6–70.9) and the specificity was 62.5% (95% CI: 35.4–84.8). The sensitivity for severe depression was 42.2% (95% CI: 30.6–52.4) and the specificity was 85.1% (95% CI: 71.7–93.8). The receiver operating curve showed an area under the curve of 0.66 (95% CI: 0.52–0.81) for any depression and of 0.72 (95% CI: 0.63–0.81) for severe depression.

Conclusion

The MDI is a conservative instrument for diagnosing ICD-10 depression in a clinical setting compared to the M-CIDI interview. Only a few false-positive diagnoses were identified when the MDI was used on clinical suspicion of depression.

Keywords:

• Major Depression Inventory
• depression
• criterion validity
• M-CIDI interview
• diagnosing

Supplementary materials

Figure S1 Major Depression Inventory, all 10 items used in our study.

Note: Reproduced from Bech P. Clinical psychometrics. Oxford: John Wiley and Sons; 2012. Copyright © 2012, John Wiley & Sons, Ltd.¹

Figure S2 GP use of psychometric tests in Denmark

Abbreviation: GP, general practitioner.

Table S1 M-CIDI interviews and MDI ICD-10 diagnosis: any depression

Table S2 M-CIDI interviews and MDI ICD-10 diagnosis: mild depression (moderate and severe depression were excluded)

Table S3 M-CIDI interviews and MDI ICD-10 diagnosis: moderate depression (mild and severe depression were excluded)

Table S4 M-CIDI interviews and MDI ICD-10 diagnosis: severe depression (mild and moderate depression were included as no severe depression)

Reference

• BechPClinical psychometricsOxfordJohn Wiley and Sons2012
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Acknowledgments

We gratefully acknowledge the persons and general practitioners who took the time to participate in our study. This work was supported by unrestricted grants from the Lund-beck Foundation (grant number: R155-2012-11280) and the Primary Health Care Research Foundation of the Central Denmark Region.

Disclosure

The authors report no conflicts of interest in this work.