Protocol for studying racial/ethnic disparities in depression care using joint information from participant surveys and administrative claims databases: an observational cohort study.

Introduction Current evidence indicates that older racial/ethnic minorities encounter disparities in depression care. Because late-life depression is common and confers major adverse health consequences, it is imperative to reduce disparities in depression care. Thus, the primary objectives of this protocol are to: (1) quantify racial/ethnic disparities in depression treatment and (2) identify and quantify the magnitude of these disparities accountable for by a multifactorial combination of patient, provider and healthcare system factors. Methods and analysis Data will be derived from the Vitamin D and Omega-3 Trial-Depression Endpoint Prevention (VITAL-DEP) study, a late-life depression prevention ancillary study to the VITAL trial. A total of 25 871 men and women, aged 50+ and 55+ years, respectively, were randomised in a 2x2 factorial randomised trial of heart disease and cancer prevention to receive vitamin D and/or fish oil for 5 years starting from 2011. Most participants were aged 65+ years old at randomisation. Medicare claims data for over 19 000 VITAL/VITAL-DEP participants were linked to conduct our study. The major study outcomes are depression treatment (antidepressant use and/or receipt of psychotherapy services) and adherence to medication treatment (antidepressant adherence and acceptability). The National Academy of Medicine framework for studying racial disparities was leveraged to select patient-level, provider-level and healthcare system-level variables and to address their potential roles in depression care disparities. Blinder-Oaxaca regression decomposition methods will be implemented to quantify and identify correlates of racial/ethnic disparities in depression treatment and adherence. Ethics and dissemination This study received Institutional Review Board (IRB) approval from the Partners Healthcare (PHS) IRB, protocol# 2010P001881. We plan to disseminate our results through publication of manuscripts patient engagement activities, such as study newsletters regularly sent out to VITAL participants, and presentations at scientific meetings.