Background: The Patient Health Questionnaire-9 (PHQ-9), a self-reported depression screening instrument for measurement-based care (MBC), may have cross-cultural measurement invariance (MI) with a regional group of American Indian/Alaska Native (AI/AN) and non-Hispanic White adults. However, to ensure health equity, research was needed on the cross-cultural MI of the PHQ-9 between other groups of AI/AN peoples and diverse populations.
Methods: We assessed the MI of the one-factor PHQ-9 model and five previously identified two-factor models between non-Hispanic AI/AN adults (ages 18-64) from healthcare systems A (n=1,759) and B (n=2,701) using secondary data and robust maximum likelihood estimation. We then tested either fully or partially invariant models for MI between either combined or separate AI/AN groups, respectively, and Hispanic (n=7,974), White (n=7,974), Asian (n=6,988), Black (n=6,213), and Native Hawaiian/Pacific Islander (n=1,370) adults from healthcare system B. All had mental health or substance use disorder diagnoses and were seen in behavioral health or primary care from 1/1/2009-9/30/2017.
Results: The one-factor PHQ-9 model was partially invariant, with two-factor models partially, or in one case fully, invariant between AI/AN groups. The one-factor model and three two-factor models were partially invariant between all seven groups, while a two-factor model was fully invariant and another partially invariant between a combined AI/AN group and other racial and ethnic groups.
Conclusions: Achieving health equity in MBC requires ensuring the cross-cultural validity of measurement tools. Before comparing mean scores, PHQ-9 models should be assessed for individual racial and ethnic group fit for adults with mental health or substance use disorders.
Keywords: American Indian/Alaska Native; Patient Health Questionnaire-9; cross-cultural; health equity; measurement equivalence; measurement invariance.