title: Systematic Literature Review and Meta-analysis of Medication Adherence With Once-weekly Versus Once-daily Therapy.
abstract: OBJECTIVE
  To compare medication adherence rates for once-weekly (QW) versus once-daily (QD) dosing regimens in patients with chronic disease.
  
  
  METHODS
  A systematic literature review was conducted to identify articles published in English-language journals examining the rate of adherence to medications in patients with chronic disease. Relevant studies were identified from January 2002 through August 2013 using PubMed, EMBASE, and the Cochrane Library databases. Twenty-two published observational studies reporting adherence were identified by 2 independent reviewers, and 7 articles reported relevant measures for analysis. All studies were conducted in patients with osteoporosis. Meta-analyses estimated (1) mean difference (MD) in adherence (defined using the mean medication possession ratio [MPR]) between QW and QD dosing groups and (2) odds ratio (OR) for adherence (defined using an MPR cutoff of ≥80%) for QW versus QD dosing. Heterogeneity was assessed using Cochran's Q and I(2) values, and meta-analyses used both fixed- and random-effects models.
  
  
  RESULTS
  The random-effects meta-analysis revealed a significantly greater MPR with QW compared with QD dosing (pooled MD = 12.29%; 95% CI, 10.76%-13.82%; n = 9 [data reported in 7 publications]). Because of the high level of heterogeneity (I(2) = 83.4%), the fixed-effects model results were not appropriate to report for the pooled MD. When examining the OR for adherence, both fixed- and random-effects models provided similar results due to the low level of heterogeneity (I(2) = 7.9%; n = 5 [data reported in 3 publications]). Using either model, the pooled odds of being adherent (MPR ≥80%) in the QW dosing group was approximately 1.9 times the odds in the QD dosing group (random-effects OR = 1.90; 95% CI, 1.81-2.00; fixed-effects OR = 1.92; 95% CI, 1.84-1.99).
  
  
  CONCLUSIONS
  In our meta-analysis, QW dosing was associated with better adherence levels and greater odds of being adherent compared with QD dosing in patients with osteoporosis.
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey. Electronic address: kristy.iglay@merck.com.
authors.forename: Kristy
authors.initials: K
authors.lastname: Iglay
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Xiting
authors.initials: X
authors.lastname: Cao
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Mavros
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Kruti
authors.initials: K
authors.lastname: Joshi
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Shengsheng
authors.initials: S
authors.lastname: Yu
authors.affiliation: Merck & Co, Inc, Kenilworth, New Jersey.
authors.forename: Kaan
authors.initials: K
authors.lastname: Tunceli
mesh_terms: D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D002908:Chronic Disease / Q000628:therapy; D004334:Drug Administration Schedule; D006801:Humans; D016017:Odds Ratio; D010024:Osteoporosis / Q000188:drug therapy*; D016903:Drug Monitoring
chemical_list: D050071:Bone Density Conservation Agents
keywords: adherence; daily dosing; dosing regimen; medication possession ratio; osteoporosis; weekly dosing