A clinically feasible short version of the 15-item geriatric depression scale extracted using item response theory in a sample of adults aged 85 years and older

Abstract

Objectives

To extract the items most suitable for a short version of the 15-item Geriatric Depression Scale (GDS-15) in a sample of adults aged ≥ 85 years using item response theory (IRT).

Method

This population-based cross-sectional study included 651 individuals aged ≥ 85 years from the Umeå 85+/GErontological Regional DAtabase (GERDA) study. Participants were either community dwelling (approximately 70%) or resided in institutional care (approximately 30%) in northern Sweden and western Finland in 2000–2002 and 2005–2007. The psychometric properties of GDS-15 items were investigated using an IRT-based approach to find items most closely corresponding to the GDS-15 cut off value of ≥5 points. Receiver operating characteristic curves were used to compare the performance of the proposed short version with that of previously proposed short GDS versions.

Results

GDS-15 items 3, 8, 12, and 13 best differentiated respondents’ levels of depressive symptoms corresponding to the GDS-15 cut off value of ≥5, regardless of age or sex, and thus comprise the proposed short version of the scale (GDS-4 GERDA). For the identification of individuals with depression (total GDS-15 score ≥ 5), the GDS-4 GERDA with a cut-off score of ≥2 had 92.9% sensitivity and 85.0% specificity.

Conclusion

The GDS-4 GERDA could be used as an optimized short version of the GDS-15 to screen for depression among adults aged ≥ 85 years.

Keywords:

• Aged
• 80 and over
• depression
• item response theory
• psychometrics
• ROC curve
• psychiatric status rating scales

Disclosure of interest

The authors reports no conflict of interest

Author contribution

All authors made substantial contributions to conception and design, and/or acquisition of data, and/or analysis and interpretation of data; participated in drafting the article or revising it critically for important intellectual content; and gave final approval of the version to be submitted.

Sponsor’s role

Funders had no role in trial design, data collection, analysis, or preparation of the manuscript.

Additional information

Funding

This work was supported by funds from the Interreg IIIA Kvarken-MittSkandia Program (2005-2007) and the Bothnia-Atlantica Program, both funded by the European Union and the European Regional Development Fund. This work was also supported by the Umeå University Foundation for Medical Research, King Gustav V’s and Queen Viktoria’s Foundation of Freemasons, Västerbotten County Council, the Strategic Research Program in Care Sciences, Norrbotten County Council, Sweden, Joint Committee of County Councils in Northern Sweden “Visare Norr” and the Swedish Research Council 2014 (Grant K2014-99X-22610-01-6).