Table 5.

Studies Reporting TNF Alpha Inhibitor Medication Persistence (n = 13).

Citation	Methods	Measure	Results	Limitations
Ostergaard et al., 2007	Retrospective review of database Medication persistence to infliximab and etanercept (N= 417)	Medication persistence	52 week medication persistence Infliximab/etanercept: 70%	Retrospective review Observation study Voluntary database Medication persistence measured-not a direct indication of adherence
Voulgari et al., 2005	Observation study evaluating a number factors related to treatment with infliximab including discontinuation rates over a 6-year period (N= 84)	Medication persistence	33% discontinuation rate Use of MTX decreased discontinuation Reaction and efficacy accounted for 30% of discontinuation	Observation study Number of endpoints Small sample size
Agarwal et al., 2005	Retrospective review of factors including medication persistence to infliximab (N = 183)	Medication persistence	Mean ± SD duration of infliximab of 58.2 ± 56.6 weeks Medication persistence at 1 year 52%	Retrospective review Medication persistence measured Not a direct indication of adherence
Kristensen et al., 2006	Prospective study comparing adherence rates between infliximab and etanercept (N= 1,161)	Medication persistence	4-year adherence Infliximab or etanercept with MTX: 36% Infliximab or etanercept (monotherapy): 18% Infliximab or etanercpet with other DMARDs: 27%	Lack of randomization Access to medications Older patients were taking infliximab as monotherapy
Harley et al., 2003	Review of pharmacy and health records 1998–2000 to compare adherence between infliximab, MTX and etanercept (N = 2,662; MTX = 1668; etanercept = 853; infliximab= 141)	Medication possession ratio	Significantly decreased compliance in patients taking etanercept and MTX when compared with infliximab	Unequal groups studied (infliximab-141; etanercept-853; methotrexate-1668) Concomitant use of other medications not discussed Medical and pharmacy record review
Dziadzio et al., 2007	Mailed survey RA and AS patients, compliance with recommendations to discontinue TNF alpha antagonist treatment while experiencing an infection (N=78)	Self-report questionnaire	27% of patients reported non-compliance with recommendations Factors reported included: fear of flare, disregarding infection as serious, advice from healthcare providers and community contacts, & concurrent treatment with antibiotics	Mailed survey Small sample size Few demographics of sample IRB approval not discussed
Grijalva et al., 2007	Retrospective review of Tennessee Medicaid database (N=14,932)	Medication persistence	Leflunomide, infliximab, adalimumab, and etanercept – higher adherent behaviors compared to methotrexate	Retrospective review Sample primarily white females in one U.S. state
Brocq et al., 2007	Retrospective review (Data collected 1999–2005) (N= 442 inflammatory arthritis patients; RA 304; AS 92; PsA 46)	Medication persistence	Medication persistence- 6 months was 89%; 12 months- 78%; 18 months- 71%; 24 months- 62%; and 50 months- 50%. Drug persistence with etanercept and adalimumab significantly greater than infliximab	Retrospective review 3 disease groups included in sample Use of adalimumab was limited due to drug unavailability Medication persistenc - not a direct indication of adherence
Hetland et al., 2008	Prospective study of Danish Danbio Registry (N =1813 in 5 cohorts)	Medication persistence	Medication persistence at 52- weeks ranged between 62 to 73%.	Limited data- use of registry Sample 72% female Age ranges 45 to 66 Medication persistence measured- not a direct indication of adherence
Wendling et al., 2005	Retrospective chart review (N= 42)	Medication persistence	Medication persistence at 36, 24, 12, and 6 months were 20%, 67%, 74% and 82% respectively	Small sample size Retrospective chart review Medication persistence measured- not a direct indication of adherence
Flendrie et al., 2003	3-year prospective study (N= 237)	Medication persistence	1-year -medication persistence l- 73%, 66%, and 74% for adalimumab, infliximab, and etanercept respectively. No difference in medication persistence between the three TNF alpha antagonists	Medication persistence measured- not a direct indication of adherence Data collected from registry
Lipsky et al., 2000	RCT (drug trial) (N= 428)	Medication persistence	-Medication persistence at 54 weeks was 73% (3mg/kg every 8 weeks); 77% (3mg/kg every 4 weeks); 86% (10mg/kg every 8 weeks); & 80% (10mg/kg every 4weeks); all subject also took MTX	Aim: investigate efficacy and safety of infliximab as opposed to determining adherence Medication persistence- not a direct measure of adherence Funding for study from manufacturer of infliximab
Maini et al., 2004	RCT (drug trial) (N=428)	Medication persistence	Medication persistence at 102 weeks was 56% (3mg/kg every 8 weeks); 55% (3mg/kg every 4 weeks); 68% (10mg/kg every 8 weeks); & 60% (10mg/kg every 4weeks); all subject also took MTX	Aim: investigate efficacy and safety of infliximab Medication persistence- not a direct measure of adherence Funding for study from manufacturer of infliximab

DMARDs = disease modifying anti-rheumatic drugs, RA = rheumatoid arthritis; PsA = psoriatic arthritis; AS = ankylosing spondylitis; MTX = methotrexate; RCT = randomized control trial