Analysis of the PHQ-15 by individual items: a systematic review and meta-analysis

Background: The Patient Health Questionnaire-15 (PHQ-15) is among the most commonly used questionnaires to assess somatic symptoms in primary care settings. The aim of our study was to conduct a systematic review and meta-analysis of the studies that have analysed individual items from the PHQ-15 to determine the influence of differences in sociodemographic and clinical variables. Methods: This systematic review was conducted in accordance with the PRISMA statement. Studies analysing PHQ-15 by individual items were searched in Medline/PubMed, Embase, PsycINFO, Scopus from 1999 to November 2019. Results: Data were extracted from 13 studies. The most frequently reported symptoms were “pain in your arms, legs, or joints”, “back pain”, “headaches”, and “feeling tired or having low energy”. In patients with mental health disorders (depression, anxiety disorder, and somatoform disorder), the most commonly reported somatic symptoms were “trouble sleeping”, “feeling tired or having low energy”, and digestive symptoms. In the meta-analysis, females scored significantly higher than males on 3 of 14 items: “headaches” (odds ratio [OR] 2.16, p<.001), “dizziness” (OR 1.58, p<.001), and “stomach pain” (OR 1.46, p<.02), with a small to moderate effect size for these differences. Conclusions: Gender differences were detected for three items (headaches, dizziness, and stomach pain), although the magnitude of these differences was small. Further research is needed to better understand the relationship between individual items and other sociodemographic variables. In addition, more research is needed to determine measurement invariance across various demographic groups. Provide a structured summary including, as applicable: background; objetives; data sources; study eligibility criteria, participants, and interventions; study appraisal and synthesis methods; results; limitations; conclusiones