AUTHOR=von Schrottenberg Victoria , Toussaint Anne , Hapfelmeier Alexander , Teusen Clara , Riedl Bernhard , Henningsen Peter , Gensichen Jochen , Schneider Antonius , Linde Klaus , Dreischulte Tobias , Falkai Peter , Gensichen Jochen , Henningsen Peter , Bühner Markus , Jung-Sievers Caroline , Krcmar Helmut , Lukaschek Karoline , Pitschel-Walz Gabriele , Schneider Antonius , Vukas Jochen , Younesi Puya , Gökce Feyza , von Schrottenberg Victoria , Schönweger Petra , Schillock Hannah , Raub Jonas , Reindl-Spanner Philipp , Hattenkofer Lisa , Kaupe Lukas , Haas Carolin , Eder Julia , Brisnik Vita , Brand Constantin , Ebert Chris , Emilia Vogel Marie , Teusen Clara , Biersack Katharina TITLE=Lessons learned from applying established cut-off values of questionnaires to detect somatic symptom disorders in primary care: a cross-sectional study JOURNAL=Frontiers in Psychiatry VOLUME=14 YEAR=2024 URL=https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2023.1289186 DOI=10.3389/fpsyt.2023.1289186 ISSN=1664-0640 ABSTRACT=Introduction

Based on two diagnostic accuracy studies in high-prevalence settings, two distinctly different combinations of cut-off values have been recommended to identify persons at risk for somatic symptom disorder (SSD) with the combination of the Patient-Health Questionnaire-15 (PHQ-15) and the Somatic Symptom Disorder—B Criteria Scale (SSD-12). We investigated whether the reported sensitivity and specificity of both recommended cut-off combinations are transferable to primary care.

Methods

In a cross-sectional study, 420 unselected adult primary care patients completed PHQ-15 and SSD-12. Patients scoring ≥9 and ≥ 23 (recommended cut-off combination #1) or ≥ 8 and ≥ 13 (recommended cut-off combination #2) were considered test-positive for SSD, respectively. To assess the validity of the reported sensitivity and specificity in different low- to high-prevalence settings, we compared correspondingly expected proportions of test positives to the proportion observed in our sample.

Results

Based on combination #1, 38 participants (9%) were found to be test positive, far fewer than expected, based on the reported values for sensitivity and specificity (expected minimum frequency 30% with a true prevalence ≥1%). This can only be explained by a lower sensitivity and higher specificity in primary care. For combination #2, 98 participants (23%) were test positive, a finding consistent with a true prevalence of SSD of 15% or lower.

Discussion

Our analyzes strongly suggest that the sensitivity and specificity estimates reported for combination #1 are not applicable to unselected primary care patients and that the cut-off for the SSD (≥23) is too strict. Cut-off combination #2 seems more applicable but still needs to be tested in studies that compare screening findings by questionnaires with validated diagnostic interviews as reference standards in primary care populations.