OBJECTIVES: To estimate the extent and identify factors associated with adherence to acute and continuation phase appropriate [based on Beers and Screening Tool of Older Persons’ potentially inappropriate Prescriptions (STOPP) criteria] antidepressant treatment among older adults (age≥65 years) with dementia and major depressive disorder (MDD).

METHODS: We conducted a retrospective cohort study using Medicare 5% data (2012-2013). We identified dementia and MDD based on previously validated claims database codes. Intake period of our study was from 01-May-2012 through 30-April-2013 and the date of first claim of an appropriate antidepressant during this intake period was considered as Index prescription start date (IPSD). Acute and continuation phase depression treatment adherence were defined as (i) ≥84 days of antidepressant use during 114 days post-IPSD; and (ii) ≥180 days of antidepressant use during 231 days post-IPSD, respectively. Factors associated with acute and continuation phase antidepressant treatment adherence were identified using multivariable logistic regression analyses.

RESULTS: Our study sample consisted of 6,239 [adherent: N=4,644 (74.44%)] and 5,617 [adherent: N=3,584 (63.81%)] older adults with dementia and MDD during acute and continuation phase treatment, respectively. Significant correlates of acute phase antidepressant adherence included: race/ethnicity, public assistance, baseline Parkinson’s disease (PD), baseline psychotherapy use, density of neurologists and psychiatrists available within the zip code. Whereas, significant correlates of continuation phase antidepressant adherence included: race/ethnicity, age group, baseline PD, and baseline antipsychotic use. For example, Whites were 30% [Adjusted Odds Ratio (AOR): 1.30, 95% CI: 1.08-1.57) and 49% (AOR: 1.49, 95% CI: 1.24-1.78) more likely to be adherent to acute and continuation phase antidepressant treatment respectively compared to other race/ethnicities.

CONCLUSIONS: Approximately 74% and 64% older adults with dementia and MDD were adherent to acute and continuation phase antidepressant treatment in this nationally representative sample of Medicare beneficiaries and we identified several modifiable and non-modifiable factors associated with adherence.