Title: PND23 HEALTHCARE EXPENDITURES ASSOCIATED WITH ADHERENCE TO ANTIDEPRESSANT MEDICATION MANAGEMENT MEASURES DURING ACUTE AND CONTINUATION PHASES OF DEPRESSION TREATMENT AMONG OLDER ADULTS WITH DEMENTIA AND MAJOR DEPRESSIVE DISORDER
Abstract: To examine healthcare expenditures associated with adherence to Healthcare Effectiveness Data and Information Set (HEDIS) antidepressant medication management (AMM) during acute and continuation phases of depression treatment among older adults (age≥65 years) with dementia and major depressive disorder (MDD). Using Medicare 5% sample data (2011-2013), we conducted a retrospective cohort study where the first antidepressant prescription claim from May 1, 2011 through April 30, 2012 was considered Index prescription start date (IPSD). We utilized HEDIS guidelines to define adherence during acute (≥ 85 days of antidepressant use during 115 days post-IPSD) and continuation (≥ 181 days of antidepressant use during 232 days post-IPSD) phase AMM. We considered nine types of expenditures (total, outpatient, pharmacy, etc.) during 365 days from end of acute/continuation phase AMM adherence as our study outcomes. We report inverse probability of treatment weighted mean expenditures (2018 US dollars), along with 95% Confidence Intervals (CIs) calculated via a non-parametric bootstrap. We used alpha=0.05/18 (Bonferroni-correction) for statistical significance, and the p-values for difference in mean expenditures were estimated using a random permutation test. During acute and continuation phase treatments, our final study samples consisted of 3,994 [adherent(N)=2,906 (72.76%)] and 3,637 [adherent(N)=2,245 (61.73%)] older adults with dementia and MDD respectively. Continuation phase adherent treatment group compared to non-adherent group had lower mean total expenditures [US$24,486 (95% CI: US$23,791-US$26,262) vs. US$28,074 (95% CI: US$25,418-US$30,005), p=0.002]. Mean pharmacy and hospice expenditures were statistically significantly higher and lower respectively between adherent and non-adherent groups during both acute and continuation phase treatments. Acute phase adherence was associated with lower mean hospice expenditures, whereas, continuation phase depression treatment adherence was associated with lower mean total and hospice expenditures compared to non-adherence. As expected, mean pharmacy expenditures were higher for adherent group during both acute and continuation phase compared to non-adherence.