Joshua J Gagne1, Aaron S Kesselheim2, Niteesh K Choudhry2, Jennifer M Polinski3, David Hutchins3, Olga S Matlin3, Troyen A Brennan3, Jerry Avorn2, William H Shrank3. 1. Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. Electronic address: jgagne1@partners.org. 2. Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. 3. CVS Health, Woonsocket, RI, USA.
Abstract
OBJECTIVE: The objective of this study was to compare treatment persistence and rates of seizure-related events in patients who initiate antiepileptic drug (AED) therapy with a generic versus a brand-name product. METHODS: We used linked electronic medical and pharmacy claims data to identify Medicare beneficiaries who initiated one of five AEDs (clonazepam, gabapentin, oxcarbazepine, phenytoin, zonisamide). We matched initiators of generic versus brand-name versions of these drugs using a propensity score that accounted for demographic, clinical, and health service utilization variables. We used a Cox proportional hazards model to compare rates of seizure-related emergency room (ER) visit or hospitalization (primary outcome) and ER visit for bone fracture or head injury (secondary outcome) between the matched generic and brand-name initiators. We also compared treatment persistence, measured as time to first 14-day treatment gap, between generic and brand-name initiators. RESULTS: We identified 19,760 AED initiators who met study eligibility criteria; 18,306 (93%) initiated a generic AED. In the matched cohort, we observed 47 seizure-related hospitalizations and ER visits among brand-name initiators and 31 events among generic initiators, corresponding to a hazard ratio of 0.53 (95% confidence interval, 0.30 to 0.96). Similar results were observed for the secondary clinical endpoint and across sensitivity analyses. Mean time to first treatment gap was 124.2 days (standard deviation [sd], 125.8) for brand-name initiators and 137.9 (sd, 148.6) for generic initiators. SIGNIFICANCE: Patients who initiated generic AEDs had fewer adverse seizure-related clinical outcomes and longer continuous treatment periods before experiencing a gap than those who initiated brand-name versions.
OBJECTIVE: The objective of this study was to compare treatment persistence and rates of seizure-related events in patients who initiate antiepileptic drug (AED) therapy with a generic versus a brand-name product. METHODS: We used linked electronic medical and pharmacy claims data to identify Medicare beneficiaries who initiated one of five AEDs (clonazepam, gabapentin, oxcarbazepine, phenytoin, zonisamide). We matched initiators of generic versus brand-name versions of these drugs using a propensity score that accounted for demographic, clinical, and health service utilization variables. We used a Cox proportional hazards model to compare rates of seizure-related emergency room (ER) visit or hospitalization (primary outcome) and ER visit for bone fracture or head injury (secondary outcome) between the matched generic and brand-name initiators. We also compared treatment persistence, measured as time to first 14-day treatment gap, between generic and brand-name initiators. RESULTS: We identified 19,760 AED initiators who met study eligibility criteria; 18,306 (93%) initiated a generic AED. In the matched cohort, we observed 47 seizure-related hospitalizations and ER visits among brand-name initiators and 31 events among generic initiators, corresponding to a hazard ratio of 0.53 (95% confidence interval, 0.30 to 0.96). Similar results were observed for the secondary clinical endpoint and across sensitivity analyses. Mean time to first treatment gap was 124.2 days (standard deviation [sd], 125.8) for brand-name initiators and 137.9 (sd, 148.6) for generic initiators. SIGNIFICANCE: Patients who initiated generic AEDs had fewer adverse seizure-related clinical outcomes and longer continuous treatment periods before experiencing a gap than those who initiated brand-name versions.
Authors: Ameet Sarpatwari; Joshua J Gagne; Zhigang Lu; Eric G Campbell; Wendy J Carman; Cheryl L Enger; Sarah K Dutcher; Wenlei Jiang; Aaron S Kesselheim Journal: J Gen Intern Med Date: 2019-01-10 Impact factor: 5.128
Authors: Maria Stella Vari; Francesca Pinto; Elisabetta Mencaroni; Giovanna Giudizioso; Carlo Minetti; Angela La Neve; Tiziana Francavilla; Marta Piccioli; Salvatore Striano; Luigi del Gaudio; Pierangelo Tovo; Pasquale Striano; Alberto Verrotti Journal: Clin Drug Investig Date: 2016-01 Impact factor: 2.859
Authors: Peter S Kirk; Tudor Borza; James M Dupree; John T Wei; Chad Ellimoottil; Megan E V Caram; Mary Burkhardt; Joel J Heidelbaugh; Brent K Hollenbeck; Ted A Skolarus Journal: Urol Pract Date: 2018-09
Authors: Leena Choi; Robert J Carroll; Cole Beck; Jonathan D Mosley; Dan M Roden; Joshua C Denny; Sara L Van Driest Journal: Bioinformatics Date: 2018-09-01 Impact factor: 6.937
Authors: Rishi J Desai; Ameet Sarpatwari; Sara Dejene; Nazleen F Khan; Joyce Lii; James R Rogers; Sarah K Dutcher; Saeid Raofi; Justin Bohn; John G Connolly; Michael A Fischer; Aaron S Kesselheim; Joshua J Gagne Journal: PLoS Med Date: 2019-03-13 Impact factor: 11.069
Authors: Rishi J Desai; Ameet Sarpatwari; Sara Dejene; Nazleen F Khan; Joyce Lii; James R Rogers; Sarah K Dutcher; Saeid Raofi; Justin Bohn; John Connolly; Michael A Fischer; Aaron S Kesselheim; Joshua J Gagne Journal: BMJ Date: 2018-04-03