Neuropsychiatric Disease and Treatment (Mar 2024)
Psychometric evaluation and linking of the PHQ-9, QIDS-C, and VQIDS-C in a real-world population with major depressive disorder
Abstract
Emily OC Palmer,1 Sheryl Ker,2 Miguel E Rentería,3 Thomas Carmody,4 A John Rush5,6 1Holmusk Europe Ltd, London, UK; 2KKT Technologies, Pte. Ltd, Singapore; 3QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia; 4Peter O’Donnell Jr. School of Public Health, University of Texas Southwestern Medical Center, Dallas, TX, USA; 5Duke University School of Medicine, Duke University School of Medicine, Durham, NC, USA; 6Clinical sciences, Duke-National University of Singapore, SingaporeCorrespondence: Emily OC Palmer, Holmusk Europe Ltd, 414 Linen Hall, 162-168 Regent St, London, W1B 5TE, UK, Email [email protected]: Major depressive disorder (MDD) is a leading cause of disability worldwide. An accurate assessment of depressive symptomology is crucial for clinical management and research. This study assessed the convergent validity, reliability, and total scale score interconversion across the 9-item Patient Health Questionnaire (PHQ-9) self-report, the 16-item Quick Inventory of Depressive Symptomatology-clinician report (QIDS-C) (two widely used clinical ratings) and the 5-item Very Brief Quick Inventory of Depressive Symptoms-clinician report (VQIDS-C), which evaluate the core features of MDD.Patients and Methods: This study leveraged electronic health record (EHR)-derived, de-identified data from the NeuroBlu Database (Version 23R1), a longitudinal behavioural health real-world platform. Classical Test Theory (CTT) and Item Response Theory (IRT) analyses were used to evaluate the reliability, validity of, and conversions between the scales. The Test Information Function (TIF) was calculated for each scale, with greater test information reflecting higher precision and reliability in measuring depressive symptomology. IRT was also used to generate conversion tables so that total scores on each scale could be compared to the other.Results: The study sample (n = 2,156) had an average age of 36.4 years (standard deviation [SD] = 13.0) and 59.7% were female. The mean depression scores for the PHQ-9, QIDS-C, and VQIDS-C were 12.9 (SD = 6.6), 12.0 (SD = 4.9), and 6.18 (SD = 3.2), respectively. The Cronbach’s alpha coefficients for PHQ-9, QIDS-C, and VQIDS-C were 0.9, 0.8, and 0.7, respectively, suggesting acceptable internal consistency. PHQ-9 (TIF = 30.3) demonstrated the best assessment of depressive symptomology, followed by QIDS-C (TIF = 25.8) and VQIDS-C (TIF = 17.7).Conclusion: Overall, PHQ-9, QIDS-C, and VQIDS-C appear to be reliable and convertible measures of MDD symptomology within a US-based adult population in a real-world clinical setting.Keywords: psychometrics, linking, patient health questionnaire, quick inventory of depressive symptoms, depression, real-world data
