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Comparisons of Persistence and Durability Among Three Oral Antidiabetic Therapies Using Electronic Prescription‐Fill Data: The Impact of Adherence Requirements and Stockpiling
Author(s) -
Greevy R A,
Huizinga M M,
Roumie C L,
Grijalva C G,
Murff H,
Liu X,
Griffin M R
Publication year - 2011
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.2011.228
Subject(s) - persistence (discontinuity) , medicine , sulfonylurea , medical prescription , metformin , clinical pharmacology , drug , covariate , pharmacology , emergency medicine , computer science , insulin , machine learning , geotechnical engineering , engineering
Two important challenges are inherent in the design of studies using prescription data from electronic health records: how to define the minimum level of adherence that would qualify as “continuous drug use” and how to handle stockpiling of medications. Generally, the sensitivity of a study's conclusions to these design choices is not analyzed. In our study, covariate adjusted Cox models were used to compare persistence and durability with respect to three common oral antidiabetic therapies in a cohort of 12,697 incident users. Assuming 50% stockpiling, sulfonylurea therapy, as compared with metformin, showed a significantly lower risk of nonpersistence (changing or stopping therapy) when no gap days were allowed (HR 0.95, P = 0.032), no significant difference when 14 gap days were allowed (HR 0.99, P = 0.536), and significantly greater risk of nonpersistence when 30 gap days were allowed (HR 1.05, P = 0.046). All the drug comparisons showed statistically significant effects in both directions, the risk of nonpersistence increasing or decreasing depending on the design parameters. Clinical Pharmacology & Therapeutics (2011); 90 6, 813–819. doi: 10.1038/clpt.2011.228