title: Medication adherence and persistence according to different antihypertensive drug classes: A retrospective cohort study of 255,500 patients.
abstract: BACKGROUND
  Suboptimal adherence to antihypertensives leads to adverse clinical outcomes. This study aims to determine and compare medication adherence and persistence to different first-line antihypertensive drug classes in a large cohort.
  
  
  METHODS
  A cohort study was performed using claims data for prescriptions in the German statutory health insurance scheme that insures approximately 90% of the population. A total of 255,500 patients with a first prescription of an antihypertensive were included and followed for 24months. Persistence was determined based on gaps in continuous dispensation. Adherence was analyzed by calculating the medication possession ratio (MPR).
  
  
  RESULTS
  Within a 2-year period, 79.3% of all incident users of antihypertensive monotherapy met the classification of non-persistence (gap >0.5 times the number of days supplied with medication) and 56.3% of non-adherence (MPR<0.8). Beta-blockers (42.5%) and angiotensin-converting enzyme inhibitors (31.9%) were the most widely prescribed drug classes. Non-persistence and non-adherence were highest for diuretics (85.4%, n=6149 and 66.3%, n=4774) and lowest for beta-blockers (77.6%, n=76,729 and 55.2%, n=54,559). The first gap of antihypertensive medication occurred in median 160-250days after initiation, and the average medication possession ratio for all drug classes was less than 0.8. Fixed combinations with diuretics showed a 19.8% lower chance for non-adherence (OR=0.802, 99.9% CI=[0.715-0.900], p<0.001) and an 8.4% lower hazard for non-persistence (HR 0.916, 99.9% CI=[0.863-0.973], p<0.001) compared with monotherapies.
  
  
  CONCLUSIONS
  This large cohort study reveals important differences in 2-year adherence and persistence between antihypertensives that were lowest for diuretics. Fixed-dose combinations with diuretics may facilitate adherence compared to single substance products. However, effective strategies to improve adherence to antihypertensives are needed regardless of drug class.
authors.affiliation: DAPI-German Institute for Drug Use Evaluation, Unter den Linden 19-23, 10117 Berlin, Germany; Department of Medicine, ABDA-Federal Union of German Associations of Pharmacists, Unter den Linden 19-23, 10117 Berlin, Germany; Department of Pharmacology, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany; Institute of Pharmacy, Department of Clinical Pharmacy and Biochemistry, Freie Universitaet Berlin, Kelchstrasse 31, 12169, Berlin, Germany. Electronic address: m.schulz@dapi.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Schulz
authors.affiliation: Department of Medicine, ABDA-Federal Union of German Associations of Pharmacists, Unter den Linden 19-23, 10117 Berlin, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Krueger
authors.affiliation: DAPI-German Institute for Drug Use Evaluation, Unter den Linden 19-23, 10117 Berlin, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Schuessel
authors.affiliation: Molecular and Clinical Pharmacy, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universitaet Erlangen/Nuremberg, Cauerstrasse 4, 91058 Erlangen, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Friedland
authors.affiliation: Department of Internal Medicine III-Cardiology, Angiology and Intensive Care Medicine, Saarland University Medical Center, Kirrberger Strasse, 66421 Homburg/Saar, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Laufs
authors.affiliation: Department of Pharmacology, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Walter E
authors.initials: WE
authors.lastname: Mueller
authors.affiliation: DAPI-German Institute for Drug Use Evaluation, Unter den Linden 19-23, 10117 Berlin, Germany; Department of Pharmacology, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main, Germany.
authors.forename: Miriam
authors.initials: M
authors.lastname: Ude
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000145:classification; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000145:classification; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000145:classification*; D015331:Cohort Studies; D016208:Databases, Factual / Q000706:statistics & numerical data*; D004232:Diuretics / Q000008:administration & dosage / Q000145:classification; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000453:epidemiology; D008297:Male; D012189:Retrospective Studies; D016903:Drug Monitoring
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D004232:Diuretics
keywords: Antihypertensive; Claims data; Cohort study; Hypertension; Medication adherence; Persistence