title: Adherence and Persistence Across Antidepressant Therapeutic Classes: A Retrospective Claims Analysis Among Insured US Patients with Major Depressive Disorder (MDD).
abstract: BACKGROUND
  Adherence and persistence to therapy, or how well a patient follows provider directions on frequency and time to discontinuation of prescribed medications, is associated with positive health outcomes, including decreased healthcare costs and patient mortality. A clear literature gap exists assessing adherence and persistence to antidepressants (ADs) in the major depressive disorder (MDD) population at clinically relevant time points and at the therapeutic class level.
  
  
  OBJECTIVE
  This study assessed adherence and persistence to specific ADs, therapeutic classes, and AD therapy overall at multiple time points among US individuals from commercial, Medicare supplemental, and Medicaid insurance plans.
  
  
  METHODS
  Patients with MDD without AD or MDD claims in the prior 6 months who initiated therapy in 2003-2014 with a selective serotonin reuptake inhibitor (SSRI), serotonin and norepinephrine reuptake inhibitor (SNRI), tricyclic AD (TCA), monoamine oxidase inhibitor (MAOI), or other AD were identified using MarketScan®databases. These databases contain information on diagnoses, billing codes, and dates of service. Adherence (proportion of days covered) and persistence (days until a 30-day gap in therapy) were calculated to AD medication, AD therapeutic class, and AD therapy overall over the first 3, 6, 9, and 12 months from the index prescription date. Multivariable logistic regression estimated the adjusted odds ratios (ORs) of adherence to initial AD medication comparing AD therapeutic classes.
  
  
  RESULTS
  For 527,907 patients, adherence to initial AD medication decreased over 3, 6, 9, and 12 months (41, 31, 24, and 21%, respectively). Similar patterns were observed for adherence to initial AD therapeutic class, AD therapy overall, and all three persistence calculations. The odds of adherence to SNRIs versus SSRIs were 20-27% greater at 3, 6, 9, and 12 months (ORs 1.20, 1.23, 1.25, 1.27, respectively; p-values all <0.0001). Similar or significantly lower odds of adherence were demonstrated for other classes versus SSRIs at 3, 6, 9, and 12 months [ORs for other ADs 0.80, 0.77, 0.74, 0.72, respectively (p-values all <0.0001); ORs for TCAs 0.46, 0.45, 0.47, 0.49, respectively (p-values all <0.0001); ORs for MAOIs 1.13, 1.0, 0.77, 0.69, respectively (p-values all >0.05)].
  
  
  CONCLUSIONS
  We found low adherence and persistence to ADs in the MDD population. Within the limitations of the insurance claims data we analysed, our results suggest that adherence may differ based on therapeutic class, as patients initiating SNRI therapy appeared to have a higher likelihood of adherence versus SSRIs over the year assessed, while the odds of adherence appeared similar or lower for other classes versus SSRIs. Further prospective research is needed to confirm these findings and determine additional drivers of these apparent differences by AD therapeutic class.
authors.affiliation: Global Health Outcomes Strategy and Research, Allergan, 2525 Dupont Drive (T2-2P), Irvine, CA, 92612-1599, USA. krkeyloun@gmail.com.
authors.forename: Katelyn R
authors.initials: KR
authors.lastname: Keyloun
authors.affiliation: Pharmaceutical Outcomes Research and Policy Program, School of Pharmacy, University of Washington, Seattle, WA, USA.
authors.forename: Ryan N
authors.initials: RN
authors.lastname: Hansen
authors.affiliation: Global Health Outcomes Strategy and Research, Allergan, 2525 Dupont Drive (T2-2P), Irvine, CA, 92612-1599, USA.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Hepp
authors.affiliation: Global Health Outcomes Strategy and Research, Allergan, 2525 Dupont Drive (T2-2P), Irvine, CA, 92612-1599, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Gillard
authors.affiliation: Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Thase
authors.affiliation: Pharmaceutical Outcomes Research and Policy Program, School of Pharmacy, University of Washington, Seattle, WA, USA.
authors.forename: Emily Beth
authors.initials: EB
authors.lastname: Devine
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000928:Antidepressive Agents / Q000494:pharmacology / Q000627:therapeutic use*; D003865:Major Depressive Disorder / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007348:Insurance, Health; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012189:Retrospective Studies; D013997:Time Factors; D014481:United States; D055815:Young Adult
chemical_list: D000928:Antidepressive Agents