Healthy Skepticism Library item: 4999
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Publication type: Journal Article
Shrank WH, Hoang T, Ettner SL, Glassman PA, Nair K, DeLapp D, Dirstine J, Avorn J, Asch SM.
The implications of choice: prescribing generic or preferred pharmaceuticals improves medication adherence for chronic conditions.
Arch Intern Med 2006 Feb 13; 166:(3):332-7
http://archinte.ama-assn.org/cgi/content/full/166/3/332
Abstract:
BACKGROUND: A large proportion of Americans are enrolled in 3-tier pharmacy benefit plans. We studied whether patients enrolled in such plans who receive generic or preferred brand-name agents when initiating chronic therapy were more adherent to treatment than those who received nonpreferred brand-name medications. METHODS: We analyzed pharmacy claims filled between October 1, 2001, and October 1, 2003, from a large health plan for 6 classes of chronic medications: 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, calcium channel blockers, oral contraceptives, orally inhaled corticosteroids, angiotensin receptor blockers, and angiotensin-converting enzyme inhibitors. We measured adherence as the proportion of days covered (PDC) in each drug class during the first year of therapy. We evaluated how the formulary status of the initial prescription (generic, preferred, or nonpreferred) influenced PDC and adequate adherence, defined as PDC greater than 80%, over the subsequent year. RESULTS: A total of 7532 new prescriptions were filled in 1 of the classes evaluated: 1747 (23.2%) for nonpreferred medications, 4376 (58.1%) for preferred drugs, and 1409 (18.7%) for generic drugs. After controlling for patient sociodemographic characteristics and drug class, PDC was 12.6% greater for patients initiated on generic medications vs nonpreferred medications (58.8% vs 52.2%; P<.001). The PDC was 8.8% greater for patients initiated on preferred vs nonpreferred medications (56.8% vs 52.2%; P<.001). Patients initiated on generic and preferred medications had 62% and 30% greater odds, respectively, of achieving adequate adherence compared with those who received nonpreferred medications. CONCLUSION: In 3-tier pharmacy benefit plans, prescribing generic or preferred medications within a therapeutic class is associated with improvements in adherence to therapy.
Keywords:
Adrenal Cortex Hormones/therapeutic use
Adult
Age Factors
Angiotensin II Type 1 Receptor Blockers/therapeutic use
Angiotensin-Converting Enzyme Inhibitors/therapeutic use
Calcium Channel Blockers/therapeutic use
Chronic Disease/drug therapy*
Contraceptives, Oral/therapeutic use
Drugs, Generic*
Female
Formularies
Humans
Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use
Insurance, Pharmaceutical Services*
Male
Patient Compliance*
Prescriptions, Drug/statistics & numerical data*
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Sex Factors
United States