Factorial structure of the patient health questionnaire-9 in long-term survivors of severe COVID-19

AI Summary

PHQ-9 displayed predominantly unidimensional structure among long-term severe COVID-19 survivors in Colombia, supported by EFA and CFA.
Unifactorial model showed superior internal consistency (α = 0.81, ω = 0.86) versus two-factor solution with lower alphas.
Fatigue item had lowest loading, suggesting overlap between long COVID fatigue and depressive symptoms and need for criterion validation against psychiatric assessment.

Front Psychol. 2026 Apr 24;17:1657877. doi: 10.3389/fpsyg.2026.1657877. eCollection 2026.

ABSTRACT

INTRODUCTION: Depression is prevalent among survivors of severe COVID-19, yet psychometric evidence for screening instruments in this population remains limited, particularly in Latin America. The factor structure of the Patient Health Questionnaire-9 (PHQ-9) remains unclear in long-term survivors of severe COVID-19. This study aimed to evaluate the psychometric properties and factor structure of the PHQ-9 in a Colombian cohort of long-term survivors of severe COVID-19.

MATERIALS AND METHODS: The PHQ-9 was administered to 177 individuals previously hospitalized with severe COVID-19, with follow-up extending up to 20 months post-discharge. Both exploratory (EFA) and confirmatory factor analyses (CFA) were conducted to evaluate competing structural models.

RESULTS: The unifactorial solution demonstrated superior internal consistency (α = 0.81, ω = 0.86) compared with the two-factor solution (Factor 1: α = 0.74; Factor 2: α = 0.61). The two-factor item distribution did not correspond to established depression frameworks. CFA showed both models had acceptable fit, but chi-square difference testing revealed no significant improvement for the two-factor model (Δχ² = 0.27, p = 0.602). The fatigue item exhibited the lowest factor loading.

CONCLUSION: The PHQ-9 demonstrated a predominantly unidimensional structure in this population. The weak performance of the fatigue item suggests potential overlap between long COVID-related fatigue and depressive symptomatology, warranting future criterion validation against structured psychiatric assessment.

PMID:42117068 | PMC:PMC13157674 | DOI:10.3389/fpsyg.2026.1657877

Document this CPD