Hayden Stewart is a Pharmacy Resident and Saadia Basit is a Clinical Pharmacy Specialist in Mental Health, both at Michael E. DeBakey Veterans Affairs Medical Center in Houston, Texas. Correspondence: Hayden Stewart (hayden.stewart@va.gov)
Author disclosures The authors report no actual or potential conflicts of interest with regard to this article.
Disclaimer The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.
To address antidepressant adherence, the US Department of Veteran Affairs (VA) adopted 2 measures from the Healthcare Effectiveness Data and Information Set: MDD43h and MDD47h. Measure MDD43h is defined as the proportion of patients with a depression diagnosis newly treated with an antidepressant medication who remained on the antidepressant medication for at least 84 out of 114 days (3 months). MDD47h is similar, but assesses patients remaining on an antidepressant medication for at least 180 out of 230 days (6 months).9 These constitute a SAIL (Strategic Analytics for Improvement and Learning) measure by which VA hospitals are compared. High performance on these measures aids in improving the comparative status of a VA facility.
To help improve performance on these measures, the VA Psychotropic Drug Safety Initiative developed the Antidepressant Nonadherence Report, which serves as a case finder for clinicians to identify veterans with low adherence and/or those overdue for a refill. The dashboard uses the medication possession ratio (MPR) to calculate adherence. While the optimal value is still widely debated, an MPR of ≥ 80% is generally accepted for many disease states.10 The dashboard defines low adherence as ≤ 60%.
As of September 2018, the Antidepressant Nonadherence Report for the Michael E. DeBakey VA Medical Center (MEDVAMC) in Houston, Texas, included > 5000 patients in both MEDVAMC and associated community-based outpatient clinics. About 30% of patients were categorized as overdue for a refill.
Study Objectives
To better understand the problem of antidepressant adherence within this population, we decided to study the relationship between antidepressant class and adherence rates, as well as how adherence relates to patient-specific characteristics. By highlighting predisposing risk factors to low adherence, we hope to provide better interventions.
The primary objective of this study was to determine whether 3-month adherence rates, measured by the MPR, differ between antidepressant classes in veterans newly initiated on antidepressant therapy. A secondary objective was to identify whether there are differences in patient characteristics between those with high MPR (≥ 80%) and low MPR (≤ 60%).
Methods
This study used a retrospective, cross-sectional chart review of MEDVAMC patients from the Antidepressant Nonadherence Report. Patients were: aged ≥ 18 years; newly initiated on an antidepressant with no previous use of the same medication; outpatient for the entire study period; and seen by a physician, physician assistant, nurse practitioner, or pharmacist mental health provider (MHP) within the 3-month study period. All patients’ charts showed a depression diagnosis—an inclusion criterion for the MDD43h and MDD47h measures. However, for this study, the indication(s) for the chosen antidepressant were determined by the MHP note in the patient electronic health record on the date that the medication was prescribed. Study patients may not have had a current depression diagnosis based upon the MHP assessment on the index date. We chose to determine the antidepressant indication(s) in this way because the MHP note would have the most detailed patient assessment.
Patients with previous use of the prescribed antidepressant were excluded because previous exposure may bias the patient and affect current adherence. Patients who were hospitalized at the VA for any reason during the 3-month study period were excluded because of a known risk during transitions of care for medications to be held or discontinued, which could impact refills and MPR. Some patients were excluded if they were taking the antidepressant for a nonmood-related indication (insomnia, neuropathy, migraine prophylaxis, etc). Patients also were excluded if the antidepressant was prescribed to take as-needed; if trazodone was the only antidepressant prescribed; if they were diagnosed with cognitive impairment including dementia or history of stroke; or if they were diagnosed with schizophrenia, schizoaffective disorder, or borderline personality disorder. Use of trazodone as the only antidepressant was excluded because of the relatively common practice to use it in the treatment of insomnia rather than depression.
