Table 1.
Characteristics of the studies included
| Reference and country | Aim/design/setting | Inclusion criteria/sample size | Follow-up | Adherence measure | Adherence criteria |
|---|---|---|---|---|---|
| Discontinuation Studies | |||||
| Bull et al24 USA | Predictors of discontinuation Cross-sectional Hospitals/outpatient clinics | Age 18–75 years MDD or depressive disorder (ICD-9 codes 296.2,311) n = 401 | Self-report | Continue with medication | |
| Demyttenaere et al17,18 Belgium | Effect of gender and impairment on adherence Prospective Primary care | Age > 18 years MDD (DSM-IV) n = 272 | 6 months | Self-report | Continue with medication |
| Hung et al47 Taiwan | Predictors of discontinuation Prospective Psychiatric hospital | Age 18–65 years MDD (DSM-IV-TR) n = 135 | 6 months | Attending follow-up appointments | Attending follow-up appointments |
| Keeley et al29 USA | Effect of somatoform symptoms on adherence Prospective Family medicine clinic | Age ≥ 18 years Depression n = 30 | 14 weeks | Self-report | Continue with medication |
| Olfson et al36 USA | Predictors of discontinuation Retrospective Medical Expenditure Panel Survey (1996–2001) | Age ≥ 18 years Depression (ICD-9 codes 296.2,296.3,300.4, or 311) n = 390 | 2.5 years (3 months for adherence) | Self-report | Continue with medication |
| Woolley et al4 US | Predictors of discontinuation Prospective Psychiatric hospital | Age 18–75 years MDD (ICD-9 codes 296.2, 296.3) n = 403 | 3 months | Self-report | Continue with medication |
| Nonadherence studies | |||||
| Aikens et al21 USA | Effect of beliefs about AD Cross-sectional Family medicine clinic | Age ≥ 18 years ≥ 12 weeks of continued AD prescriptions for treating depression n = 95 | Self-report: Brief Med Questionnaire (BMQ), Morisky Compliance Scale (MCS) | Recent (BMQ): number of days adherent/14 (continuous measure) General: MCS (continuous measure) | |
| Akincigil et al22 USA | Predictors of adherence Retrospective Private insurance health | Age ≥ 18 years Newly MDD n = 43 12 | 33 weeks | Prescription records | Acute: MPR ≥ 75% of the time during the first 16 weeks |
| Ayalon et al23 USA | plan database (January 2003 to January 2005) Adherence in elderly black and Latino patients Cross-sectional | Age a 55 years MDD n = 101 | Self-report | Continuation: MPR ≥ 75% of the time during weeks 17–33 Intentional and nonintentional (both dichotomized) | |
| University of California San Francisco patient registry system | |||||
| Burra et al43 Canada | Predictors of adherence Cross-sectional General hospital outpatient psychiatric practice/community outpatient psychiatric practice/general hospital-based mood disorders clinic | Age ≥ 18 years Unipolar depression n = 80 | Self-report | Taken as prescribed ≥ 80% of time | |
| Chen et al25 USA | Predictors of guide-line concordant use Retrospective National health plan database (newly diagnosed July 2000 to December 2002) | Age ≥ 18 years MDD (ICD-9-CM codes 296.20–296.24)n = 4l02 | 9 months | Prescription records | Both MPR = days of supply/total days ≥ 80% (adherence) AND no gaps of more than half of the days of supply since the end of the last supply (persistence) |
| Cohen et al44 CanadaCrown et al26 USA | Effect of personality on adherence Prospective Depression clinicImpact of adherence on long-term costs of treatment Retrospective MarketScan database (1993–1996) | Age ≥ 18 years MDE not suffering from psychosis n = 65Age ≥ 18 years MDD, neurotic depression, brief or prolonged depressive reaction, depression not elsewhere classified n = 2.030 | 14 weeks24 months (6 months for adherence) | MEMSPrescription records | Once daily: (days with at least one opening/total days) × 100 (continuous measure) Twice daily: (days with at least 2 openings/total days) × 100 (continuous measure) At least 4 prescriptions filled in the first 6 months |
| Donohue et al27 USA | Effect of pharmaceutical promotion on treatment continuation Retrospective MarketScan database (July 1997 to June 2000) | Age 18–64 years Depressive disorders (ICD-9 codes 296.2×, 296.3×, 311×, 300.4×) n = 11,306 | 6 months | Prescription records | Prescriptions filled for at least 4 months |
| Granger et al28 USA | Preferences and adherence to treatment with Wellbutrin SR Cross-sectional Online panel | Age MDE not suffering from psychosi 18 years Depression n = 527 | Self-report | As many times per day as prescribed | |
| Lin et al31 USA | Internet survey Adherence and health care expenditure Retrospective Medical Expenditure Panel Survey database (2004–2007) | Age ≥ 18 years MDD (ICD-9 codes 296.2, 296.3) n = 2,111,615 (weighted number) | 12 months | Prescription records | Proportion of days covered = ((number of days with drug on hand)/365) × 100 (continuous measure) |
| Madsen et al32 USA | Provider collaboration and patient reactance in the prediction of adherence Prospective Psychiatry clinics | Age ≥ 18 years MDD n = 50 | 12 weeks | Self-report | Proportion of days adherent = (number of self-reported days of not taking medication/number of days since baseline) — 1 (continuous measure) |
| Maidment et al45 UK | Predictors of adherence in older adults Cross-sectional Primary care | Age ≥ 65 years Depression n = 67 | Self-report (score range: 1–5) | Continuous measure | |
| McLaughlin et al33 USA | Difference on adherence between once-daily versus twice-daily bupropion Retrospective NDC Health's Intelligent Health Repository (September 2003 to February 2004) | Age ≥ 18 years Depression (ICD-9 codes 296.2, 296.3, 300.4, or 311) n = 3138 | 9 months | Prescription records | MPR = (days supplied/total days) > 70% |
| Merrick et al34 USA | Customization and adherence Retrospective Medicaid claims for prescription drugs and medical services from the US states of Michigan and | Age ≥ 18 yearsDepressive disorders (ICD-9 codes 296.20–296.25, 296.30–296.35, 298.0, 300.4,309.1 and 311) n = 383 | 4 months | Prescription records | At least 84 days during the 114-day post-index observation period |
| Oller-Canet et al46 Spain | Indiana (2000–2003) Adherence to treatment Cross-sectional Primary care | Age ≥ 18 years Depressive disorders (depressive episodes; recurrent depressive disorder; dysthymia; mixed anxious depressive disorder; adaptive disorder) n = 212 | Prescription records | (Number of prescriptions prescribed — number of prescriptions dispensed) < 3 | |
| Pfeiffer et al35 USA | Effect of taking benzodiazepines on adherence to AD Retrospective VA National Registry for Depression (October 2006 to September 2007) | Depressive disorders (MDD, dysthymia, depression not otherwise specified, adjustment disorder with depressed mood) n = 43,915 | 12 months | Prescription records | MPR ≥ 72 of 90 days |
| Roca et al4s SpainRussell et al50 New Zealand | Predictors of adherence Cross-sectional Psychiatric practice Effect of beliefs about AD on adherence Cross-sectional Primary care | Age ≥ 18 years Nonpsychotic MDD (DSM-IV) N = 3606Age 18–65 years MDD (DSM-IV-R) n = 85 | Physician-rated: simplified medication adherence questionnaire Self-report: medication adherence report scale | Adherent (yes/no) Continuous measure | |
| Sher et al19 (subsample of Sirey et al)20 USA | Effect of caregivers’ perceived stigma and causal beliefs on patients' adherence Prospective Outpatient mental health clinic | Age 18–65 years Unipolar MDD (DSM-IV) n = 50 | 3 months | Self-report (score range 1–6) | Score of 6 |
| Sirey et al20 USA | Effect of perceived stigma and self-rated severity on adherence Prospective Outpatient mental health clinic | Age 18–65 years Unipolar MDD (DSM-IV) n = 134 | 3 months | Self-report (score range 1–6) | Score of 6 |
| Stang et al38 USA | To compare difference in adherence between once-daily versus twice-daily bupropion Retrospective Integrated health care Information services National managed care Benchmark database | Age 18–64 years Depressive disorders (ICD-9-CM codes 296.2, 296.3, 300.4, or 311) n = 2291 | 9 months | Prescription records | MPR = days supplied/total days (>70%) |
| Voils et al35 USA | Social support and locus of control as predictor of adherence Prospective University psychiatric service | Age ≥ 59 years CES-D ≥ 16 or major depression n = 85 | 12 months | Self-report: Morisky compliance scale | Continuous measure |
| White et al40 USA | Economic impact of patient adherence Retrospective | Age ≥ 18 years Depression n = 14,190 | 6 months | Prescription records | MPR = days supplied/total days (>70%) |
| Yeh et al48 Taiwan | Predictors of adherence Cross-sectional Outpatient services at a department of psychiatry | Age ≥ 18 years MDD and dysthymic disorder (DSM-IV) n = 181 | Self-report | Continuous measure | |
| Discontinuation/nonadherence studies | |||||
| Keeley et al30 USA | Association between responses to neutral facial expressions and adherence Prospective Primary care | Age ≥ 18 years Depression n = 22 | 3 months | Self-report Pharmacy records | Continue with medication Continuous medication availability = (days supplied/total days) × 100 |
| Sanglier et al37 USA | Adherence in older and younger adults Retrospective IMS LifeLink Healthplan database (2002–2007) | Age ≥ 18 years Depressive disorders (ICD-9-CM codes 296.2, 296.3, 300.4, or 311) n = 6460 | 6 months | Pharmacy records | Nonpersistence: no prescription filled within twice the period covered by the latest prescription fill Adherence: derivation of the MPR = number of days covered by any antidepressant dispensing/180 (<0.20, poor; 0.20–0.79, intermediate; ≥0.80, good) |
| Wu et al42 USA | Race, anxiety, and AD adherence Retrospective MarketScan database (2003–2007) | Age 18–64 years MDD (ICD-9-CM codes 296.2, or 296.3) n = 3083 | 12 months | Prescription records | MPR modified = days supplied/total days (>80%) Persistence = number of days from the date of the first antidepressant filled to the cessation of antidepressant use |
Abbreviations: AD, antidepressant; CES-D, Center for Epidemiologic Studies Depression Scale; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, Text Revision; MDD, major depressive disorder; MDE, major depressive episode; MPR, medication possession ratio; MEMS, Medication Event Monitoring System; BMQ, Beliefs about Medicines Questionnaire; MCS, multiple chemical sensitivity; VA, Veterans Administration.