title: Effect of medication dosing frequency on adherence in chronic diseases.
abstract: OBJECTIVE
  To systematically review available data on the effect of daily medication dosing frequency on medication adherence in chronic disease states, as assessed by precise medication event monitoring systems (MEMS).
  
  
  METHODS
  Systematic review of relevant literature published between January 1986 and August 2007.
  
  
  METHODS
  Four electronic databases were searched to identify appropriate studies. Study selection criteria included prospective study design, patient population with quiescent chronic disease, medication intervention prescribed to each treatment arm for at least 6 weeks, and the use of MEMS to measure adherence. Data were extracted on the chronic disease being treated, the frequency of medication dosing, and the proportion of days with correct number of doses.
  
  
  RESULTS
  Twenty studies met the selection criteria. All studies reported higher adherence rates in patients using less frequently dosed medications, and these differences were statistically significant (P <.05) in 75% (15 of 20) of studies. For 5 of 6 studies comparing once-daily versus thrice-daily dosing, patients receiving once-daily dosing had 22% to 41% more adherent days compared with patients receiving thrice-daily dosing. For studies comparing once-daily versus twice-daily dosing, patients receiving once-daily dosing had 2% to 44% more adherent days compared with patients receiving twice-daily dosing, with most studies clustering around 13% to 26%.
  
  
  CONCLUSIONS
  Patients are more compliant with once-daily compared with twice-daily or thrice-daily treatment regimens.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, USA. sdsaini@umich.edu
authors.forename: Sameer D
authors.initials: SD
authors.lastname: Saini
authors.forename: Philip
authors.initials: P
authors.lastname: Schoenfeld
authors.forename: Kellee
authors.initials: K
authors.lastname: Kaulback
authors.forename: Marla C
authors.initials: MC
authors.lastname: Dubinsky
mesh_terms: D002908:Chronic Disease / Q000188:drug therapy*; D004334:Drug Administration Schedule; D006801:Humans; D010349:Patient Compliance; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*
chemical_list: D004364:Pharmaceutical Preparations