Prescription refill records as a screening tool to identify antidepressant non-adherence.
OBJECTIVE
Non-adherence is a significant problem with antidepressants. Identifying patients at highest risk for discontinuing antidepressant treatment can be used to target clinical management. Accordingly, our purpose was to determine the shortest gap in medication supply that is predictive of discontinuation, while minimizing false positive results.


METHODS
A retrospective cohort study of medical and prescription claims from a national health plan affiliated with i3 Innovus. Sensitivities, specificities, and positive and negative predictive values were calculated for gap lengths to assess how well they predicted discontinuation. Continuously insured individuals aged 18-65 with newly diagnosed major depression and an antidepressant prescription within 45 days of diagnosis were included. Gap length was defined as the maximum number of continuous days without medication supply during acute phase treatment. Discontinuation was defined as a continuous gap of 30 or more days between an expected refill and actual refill.


RESULTS
Of 4545 eligible patients, 73% discontinued antidepressant treatment during the study period. A maximum continuous gap of 14 days had a sensitivity of 87% and a specificity of 82% for predicting discontinuation. In analyses that varied the way gaps and discontinuation were defined, gap lengths between 8 and 19 days were highly predictive of discontinuation without exceeding a 20% false positive rate.


CONCLUSIONS
Based on administrative pharmacy records, screening for gaps in medication supply of at least 14 days can accurately identify four of every five patients at risk for discontinuing. This early indicator can be used to target clinical interventions.
Hansen
Richard A
RA
Division of Pharmaceutical Outcomes and Policy, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. rahansen@unc.edu
Dusetzina
Stacie B
SB
Dominik
Rosalie C
RC
Gaynes
Bradley N
BN
D000328:Adult; D000928:Antidepressive Agents / Q000008:administration & dosage / Q000627:therapeutic use; D015331:Cohort Studies; D003863:Depression / Q000188:drug therapy; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D017723:Drug Utilization Review / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007345:Insurance Claim Review; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D016903:Drug Monitoring
D000928:Antidepressive Agents