Association between comorbid depression, antidepressant adherence, and disease-modifying therapy adherence among Texas Medicaid patients with sickle cell disease

BACKGROUND: Depression is a common mental health comorbidity among patients with sickle cell disease (SCD) and is associated with increased health care utilization, increased costs, and poorer quality of life. Although depression and antidepressant adherence have been shown to be associated with medication adherence in other chronic conditions, research examining these associations in SCD is lacking. OBJECTIVE: To determine whether comorbid depression and antidepressant medication adherence are associated with adherence to SCD disease-modifying therapies (DMTs) among Texas Medicaid patients with SCD. METHODS: This retrospective study analyzed Texas Medicaid claims data (01/2016 to 08/2023) for individuals who had at least 3 medical claims for SCD, had at least 1 prescription claim for an SCD DMT, were aged 8 to 63 years, and were continuously enrolled for 6 months before and 12 months after the index date (first claim for an SCD DMT). In addition to the above, patients with depression had at least 1 medical claim for a depressive disorder, and those with treatment had at least 1 prescription claim for a selective serotonin reuptake inhibitor or serotonin-norepinephrine reuptake inhibitor. Adherence was measured using proportion of days covered (PDC). Descriptive and inferential statistics were used to describe and compare demographic and clinical characteristics and medication adherence between patients with SCD with or without comorbid depression. Multivariable logistic regression was used to determine the association between comorbid depression, antidepressant adherence, and SCD DMT adherence. RESULTS: = 0.0026). Among patients with SCD and comorbid depression with treatment, mean adherence to selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors was 43.2 ± 29.1% and 42.3 ± 30.8%. Overall mean adherence to antidepressants was 43.3 ± 29.8%, and 20.5% (PDC ≥ 80%) and 23.5% (PDC ≥ 70%) of patients were adherent. After adjusting for covariates, the multivariable logistic regression model showed that compared with antidepressant-nonadherent patients, antidepressant-adherent patients had higher odds (adjusted odds ratio = 16.70; 95% CI = 3.97-70.31) of being adherent to SCD DMTs (PDC ≥ 70%) among patients with SCD and comorbid depression events. CONCLUSIONS: More than one-third of patients with SCD had depression, and depression was associated with lower SCD DMT adherence. Antidepressant-adherent patients had higher odds of being adherent to SCD DMTs. Providers should regularly screen for depression and initiate and encourage antidepressant adherence, as this may potentially improve adherence to SCD DMTs. Given the known association between medication adherence and health outcomes, improving adherence to SCD DMTs may improve the health outcomes in this population.