Comparative Assessment of Adherence Measures and Resource Use in SSRI/SNRI-Treated Patients with Depression Using Second-Generation Antipsychotics or L-Methylfolate as Adjunctive Therapy

BACKGROUND: Antidepressant monotherapy is effective in achieving treatment remission in only approximately one third of patients with depression, and even switching to a second antidepressant brings the cumulative remission rate to only 50%-55%. This has led to an interest in augmentation therapy for the management of treatment-resistant depression. OBJECTIVES: To assess (a) selective serotonin reuptake inhibitor/selective norepinephrine reuptake inhibitor (SSRI/SNRI) adherence when augmented with second-generation atypical antipsychotics (SGAs) or L-methylfolate using a modified application of the Healthcare Effectiveness Data and Information Set (HEDIS) acute medication management (AMM) measures at the time of augmentation, and (b) the depression-specific and total health care cost, comparing the 2 forms of augmentation therapy in the treatment of depressive disorder. METHODS: Patients with a diagnosis of depression and a pharmacy claim for an SSRI/SNRI between January 1, 2006, and December 31, 2009 (index date), and receiving concomitant augmentation therapy with either an SGA or L-methylfolate (augmentation date), were identified in the MarketScan database and followed for 231 days (follow-up). Patients were excluded for having any pharmacy claim for an antidepressant or SGA 90 days pre-index; having an L-methylfolate claim 6 months pre-index; age less than 18 years on the index date; or a diagnosis of pregnancy, dementia, psychotic-related mental disorders, Alzheimer’s disease, or Parkinson’s disease in the 12-month pre-index period. Propensity score matching (3:1 ratio, atypical antipsychotic to L-methylfolate) was used to select the final study cohorts, using covariates of age, gender, comorbidities, index SSRI/SNRI, and index SSRI/SNRI dose. Adherence to antidepressant therapy was measured from the augmentation date and included a modified application of the HEDIS (mHEDIS) AMM acute and chronic phase measures as well as the 6-month medication possession ratio. Health care utilization and cost were measured for the 6-month postaugmentation period and included both total as well as depression-related utilization/cost. Comparisons between the closely matched SGA and L-methylfolate-augmented cohorts were made using chi-square tests for binary measures and t-tests for continuous measures. RESULTS: Following propensity score matching, 4,053 SGA and 1,351 L-methylfolate patients were found to have augmentation of the index SSRI/SNRI within 12 months of the index date. The comparison groups were well matched on age, gender, comorbidities, and the type and dose of the SSRI/SNRI being augmented. The most common antidepressants augmented in both groups were escitalopram, duloxetine, and venlafaxine. Mean (standard deviation [SD]) time from index to augmentation was 73.5 [96.7] days for SGA and 105.9 [108.7] days for L-methylfolate (P less than 0.001). The most common SGAs utilized for augmentation were quetiapine, aripiprazole, and risperidone. L-methylfolate was primarily dosed at 7.5 mg/day. The mHEDIS AMM acute phase measure was met by 68.7% of the SGA cohort and 78.7% of the L-methylfolate cohort (P less than 0.001). The mHEDIS continuation phase measure was met by 50.3% of the SGA cohort and 62.1% of the L-methylfolate cohort (P less than 0.001) following augmentation. Medical utilization (inpatient, emergency department, and outpatient) was significantly higher for the SGA group, while total prescription utilization was significantly higher in the L-methylfolate group. Mean [SD] total 6-month postaugmentation costs for the SGA group was $8,499 [$13,585] and $7,371 [$12,404] for the L-methylfolate group (P = 0.005), and 6-month depression-related costs were $2,688 [$4,201] for the SGA group and $1,613 [$2,315] for the L-methylfolate group (P less than 0.001). CONCLUSIONS: Patients who augmented SSRI/SNRI therapy with SGA or L-methylfolate achieved mHEDIS AMM acute phase and continuation phase adherence scores of 69%-79% and 50%-62%, respectively. These modified scores exceeded the 2012 national median benchmarks for unmodified HEDIS AMM measures for commercial health plans. In this study, augmentation with L-methylfolate was associated with significantly higher adherence measures compared with augmentation with SGA. In addition, health care utilization and total health care costs, as well as depression-related costs, were significantly lower in the L-methylfolate augmentation group compared with augmentation with SGA.