title: Adherence to prescribed antihypertensive drug treatments: longitudinal study of electronically compiled dosing histories.
abstract: OBJECTIVE
  To describe characteristics of dosing history in patients prescribed a once a day antihypertensive medication.
  
  
  METHODS
  Longitudinal database study.
  
  
  METHODS
  Clinical studies archived in database for 1989-2006.
  
  
  METHODS
  Patients who participated in the studies whose dosing histories were available through electronic monitoring.
  
  
  METHODS
  Persistence with prescribed antihypertensive treatment and execution of their once a day drug dosing regimens.
  
  
  RESULTS
  The database contained dosing histories of 4783 patients with hypertension. The data came from 21 phase IV clinical studies, with lengths ranging from 30 to 330 days and involving 43 different antihypertensive drugs, including angiotensin II receptor blockers (n=2088), calcium channel blockers (n=937), angiotensin converting enzyme inhibitors (n=665), beta blockers (n=195), and diuretics (n=155). About half of the patients who were prescribed an antihypertensive drug had stopped taking it within one year. On any day, patients who were still engaged with the drug dosing regimen omitted about 10% of the scheduled doses: 42% of these omissions were of a single day's dose, whereas 43% were part of a sequence of several days (three or more days-that is, drug "holidays"). Almost half of the patients had at least one drug holiday a year. The likelihood that a patient would discontinue treatment early was inversely related to the quality of his or her daily execution of the dosing regimen.
  
  
  CONCLUSIONS
  Early discontinuation of treatment and suboptimal daily execution of the prescribed regimens are the most common facets of poor adherence with once a day antihypertensive drug treatments. The shortfalls in drug exposure that these dosing errors create might be a common cause of low rates of blood pressure control and high variability in responses to prescribed antihypertensive drugs.
authors.affiliation: Pharmionic Research Center, Rue des Cyclistes Frontière 24, 4600 Visé, Belgium. bernard.vrijens@pharmionic.com
authors.forename: Bernard
authors.initials: B
authors.lastname: Vrijens
authors.forename: Gäbor
authors.initials: G
authors.lastname: Vincze
authors.forename: Paulus
authors.initials: P
authors.lastname: Kristanto
authors.forename: John
authors.initials: J
authors.lastname: Urquhart
authors.forename: Michel
authors.initials: M
authors.lastname: Burnier
mesh_terms: D000959:Antihypertensive Agents / Q000008:administration & dosage*; D015331:Cohort Studies; D004334:Drug Administration Schedule; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D008137:Longitudinal Studies; D016347:Medical Records Systems, Computerized; D010349:Patient Compliance / Q000706:statistics & numerical data*
chemical_list: D000959:Antihypertensive Agents