Association Between Patient Health Questionnaire-4 Composite Score and Depression Diagnoses in a Free Clinic Setting:...

Area of Science:

• Mental Health Research
• Clinical Diagnostics
• Health Services Research

Background:

• Student-run free clinics (SRFCs) serve vulnerable populations with limited access to mental healthcare.
• The Patient Health Questionnaire-4 (PHQ-4) is a brief screening tool for depression and anxiety.
• Predictive validity of the PHQ-4 in SRFC settings requires further examination.

Purpose of the Study:

• To assess the predictive validity of the PHQ-4 for identifying Major Depressive Disorder (MDD) diagnoses.
• To evaluate the PHQ-4 as a screening tool in a student-run free clinic network.
• To explore potential disparities in MDD diagnosis rates across demographic groups.

Main Methods:

• Pooled cross-sectional study using electronic health record data from a network of SRFCs.
• Included adult patients (n=2,498) who completed PHQ-4 screening and had an ICD-10 depression code.
• Multivariable logistic regression analyzed the association between PHQ-4 scores and MDD diagnosis, adjusting for covariates.

Main Results:

• Higher PHQ-4 composite scores significantly predicted increased odds of an MDD diagnosis (aOR=2.047, p<0.001).
• The average PHQ-4 score was 1.17, with 47.2% of patients scoring ≥1.
• Non-White patients showed significantly lower odds of receiving an MDD diagnosis compared to White patients.

Conclusions:

• The PHQ-4 demonstrates strong predictive validity for MDD in free clinic settings.
• The PHQ-4 is an efficient, low-burden tool for mental health screening in underserved populations.
• Disparities in MDD diagnosis warrant further investigation and targeted interventions.