title: Medication persistence and the use of generic and brand-name blood pressure-lowering agents.
abstract: BACKGROUND
  Because of their lower cost, healthcare systems recommend physicians to prefer generic products, rather than brand-name medicaments. There is then considerable interest and debate concerning safety and effectiveness of generic products. Few studies have compared patients treated with brand-name and generic drugs for adherence to treatment, with somewhat inconsistent results. The primary objective of this study was to compare the risk of discontinuing antihypertensive drug therapy in patients treated with generic or brand-name agents.
  
  
  METHODS
  The 101,618 beneficiaries of the Healthcare system of Lombardy, Italy, aged 18 years or older who were newly treated on monotherapy with antihypertensive generic or brand-name drugs during 2008, were followed until the earliest date among those of the occurrence of treatment discontinuation to whatever antihypertensive drug therapy (outcome), or censoring (death, emigration, 12 months after treatment initiation). Hazard ratios of discontinuation associated with starting on generic or brand-name products (intention-to-treat analysis), and incidence rate ratio of discontinuation during periods on generic and brand-name products (as-treated analysis) were respectively estimated from a cohort and self-controlled case series analyses.
  
  
  RESULTS
  Patients who started on generics did not experience a different risk of discontinuation compared with those starting on brand-name agents (hazard ratio: 1.00; 95% confidence interval 0.98-1.02). Discontinuation did not occur with different rates during periods covered by generics or brand-name agents (incidence rate ratio: 1.01; 95% confidence interval 0.96-1.11) within the same individuals. A number of sensitivity and subgroup analyses confirmed the robustness of these findings.
  
  
  CONCLUSIONS
  Generic products are not responsible for the high rate of discontinuation from antihypertensive drug therapy. Assuming therapeutic equivalence, clinical implication is of prescribing generic drug therapies.
authors.affiliation: aDepartment of Statistics and Quantitative Methods, Unit of Biostatistics, Epidemiology and Public Health, University of Milano-Bicocca bDepartment of Epidemiology, Istituto di Ricerche Farmacologiche 'Mario Negri' cDepartment of Clinical Sciences and Community Health, University of Milano, Milan, Italy dInternational Prevention Research Institute (IPRI), Lyon, France eDepartment of Pharmacological Sciences fCentre for Pharmacoepidemiology and Pharmacoutilization, University of Milano, Milan gDepartment of Clinical and Experimental Sciences, University of Brescia, Brescia hDepartment of Experimental and Clinical Medicine, University of Firenze, Firenze iOperative Unit of Territorial Health Services, Region Lombardia jIRCCS, Istituto Auxologico Italiano kCentre for Clinical Physiology and Hypertension, University of Milano-Bicocca, Milan, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Corrao
authors.forename: Davide
authors.initials: D
authors.lastname: Soranna
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.forename: Alberico
authors.initials: A
authors.lastname: Catapano
authors.forename: Enrico
authors.initials: E
authors.lastname: Agabiti-Rosei
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Gensini
authors.forename: Luca
authors.initials: L
authors.lastname: Merlino
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mancia
mesh_terms: D000959:Antihypertensive Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015331:Cohort Studies; D016568:Drugs, Generic; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007558:Italy; D010349:Patient Compliance
chemical_list: D000959:Antihypertensive Agents; D016568:Drugs, Generic