Harel D.Levis B.Sun Y.Fischer F.Ioannidis J.P.A.Cuijpers P.Patten S.B.Ziegelstein R.C.Markham S.Benedetti A.Thombs B.D.He C.Wu Y.Krishnan A.Mani Bhandari P.Neupane D.Negeri Z.Imran M.Rice D.B.Riehm K.E.Azar M.Levis A.W.Boruff J.Gilbody S.Kloda L.A.Amtmann D.Ayalon L.Baradaran H.R.Beraldi A.Bernstein C.N.Bhana A.Imma Buji R.Chagas M.H.C. N. Chan J.Fong Chan L.Chibanda D.Conway A.Daray F.M.de Man-van Ginkel J.M.Diez-Quevedo C.Field S.R. W. Fisher J.Fung D.Garman E.C.Flisher A.J.Gelaye B.Gholizadeh L.Gibson L.J.Green E.P.Hall B.J.Hantsoo L.Haroz E.E.Härter M.Hegerl U.Hides L.Hobfoll S.E.Honikman S.Hudson M.Hyphantis T.Inagaki M.Jin Jeon H.Jetté N.Khamseh M.E.Köhler S.Kohrt B.A.Kwan Y.Lamers F.Asunción Lara M.Levin-Aspenson H.F.Liu S.I.Lotrakul M.Loureiro S.R.Löwe B.Luitel N.P.Lund C.Ann Marrie R.Marx B.P.Mohd Sidik S.Munhoz T.N.Muramatsu K.E. M. Nakku J.Navarrete L.Osório F.L.Persoons P.Picardi A.Pugh S.L.Quinn T.J.Rancans E.Rathod S.D.Reuter K.Rowe H.J.Santos I.S.Schram M.T.Shaaban J.Shinn E.H.Spangenberg L.Stafford L.Sung S.C.Suzuki K.Lin Lynnette Tan P.Mahidol University2023-06-182023-06-182022-08-01Methods Vol.204 (2022) , 300-31110462023https://repository.li.mahidol.ac.th/handle/20.500.14594/83666Shortened versions of self-reported questionnaires may be used to reduce respondent burden. When shortened screening tools are used, it is desirable to maintain equivalent diagnostic accuracy to full-length forms. This manuscript presents a case study that illustrates how external data and individual participant data meta-analysis can be used to assess the equivalence in diagnostic accuracy between a shortened and full-length form. This case study compares the Patient Health Questionnaire-9 (PHQ-9) and a 4-item shortened version (PHQ-Dep-4) that was previously developed using optimal test assembly methods. Using a large database of 75 primary studies (34,698 participants, 3,392 major depression cases), we evaluated whether the PHQ-Dep-4 cutoff of ≥ 4 maintained equivalent diagnostic accuracy to a PHQ-9 cutoff of ≥ 10. Using this external validation dataset, a PHQ-Dep-4 cutoff of ≥ 4 maximized the sum of sensitivity and specificity, with a sensitivity of 0.88 (95% CI 0.81, 0.93), 0.68 (95% CI 0.56, 0.78), and 0.80 (95% CI 0.73, 0.85) for the semi-structured, fully structured, and MINI reference standard categories, respectively, and a specificity of 0.79 (95% CI 0.74, 0.83), 0.85 (95% CI 0.78, 0.90), and 0.83 (95% CI 0.80, 0.86) for the semi-structured, fully structured, and MINI reference standard categories, respectively. While equivalence with a PHQ-9 cutoff of ≥ 10 was not established, we found the sensitivity of the PHQ-Dep-4 to be non-inferior to that of the PHQ-9, and the specificity of the PHQ-Dep-4 to be marginally smaller than the PHQ-9.Biochemistry, Genetics and Molecular BiologyArticleSCOPUS10.1016/j.ymeth.2021.11.0052-s2.0-851208068871095913034780986