title: Meta-analysis: impact of drug class on adherence to antihypertensives.
abstract: BACKGROUND
  Observational studies suggest that there are differences in adherence to antihypertensive medications in different classes. Our objective was to quantify the association between antihypertensive drug class and adherence in clinical settings.
  
  
  RESULTS
  Studies were identified through a systematic search of English-language articles published from the inception of computerized databases until February 1, 2009. Studies were included if they measured adherence to antihypertensives using medication refill data and contained sufficient data to calculate a measure of relative risk of adherence and its variance. An inverse-variance-weighted random-effects model was used to pool results. Hazard ratios (HRs) and odds ratios were pooled separately, and HRs were selected as the primary outcome. Seventeen studies met inclusion criteria. The pooled mean adherence by drug class ranged from 28% for β-blockers to 65% for angiotensin II receptor blockers. There was better adherence to angiotensin II receptor blockers compared with angiotensin-converting enzyme inhibitors (HR, 1.33; 95% confidence interval, 1.13 to 1.57), calcium channel blockers (HR, 1.57; 95% confidence interval, 1.38 to 1.79), diuretics (HR, 1.95; 95% confidence interval, 1.73 to 2.20), and β-blockers (HR, 2.09; 95% confidence interval, 1.14 to 3.85). Conversely, there was lower adherence to diuretics compared with the other drug classes. The same pattern was present when studies that used odds ratios were pooled. After publication bias was accounted for, there were no longer significant differences in adherence between angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors or between diuretics and β-blockers.
  
  
  CONCLUSIONS
  In clinical settings, there are important differences in adherence to antihypertensives in separate classes, with lowest adherence to diuretics and β-blockers and highest adherence to angiotensin II receptor blockers and angiotensin-converting enzyme inhibitors. However, adherence was suboptimal regardless of drug class.
authors.affiliation: Division of General Internal Medicine, Mount Sinai School of Medicine, New York, NY, USA. ian.kronish@mssm.edu
authors.forename: Ian M
authors.initials: IM
authors.lastname: Kronish
authors.forename: Mark
authors.initials: M
authors.lastname: Woodward
authors.forename: Ziad
authors.initials: Z
authors.lastname: Sergie
authors.forename: Gbenga
authors.initials: G
authors.lastname: Ogedegbe
authors.forename: Louise
authors.initials: L
authors.lastname: Falzon
authors.forename: Devin M
authors.initials: DM
authors.lastname: Mann
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000145:classification / Q000627:therapeutic use; D057911:Angiotensin Receptor Antagonists / Q000145:classification / Q000627:therapeutic use; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000145:classification / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000145:classification* / Q000627:therapeutic use*; D002121:Calcium Channel Blockers / Q000145:classification / Q000627:therapeutic use; D004232:Diuretics / Q000145:classification / Q000627:therapeutic use; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000453:epidemiology; D055118:Medication Adherence
chemical_list: D000319:Adrenergic beta-Antagonists; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D004232:Diuretics