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Use of demographic and pharmacy data to identify patients included within both the Clinical Practice Research Datalink (CPRD) and The Health Improvement Network (THIN)
Author(s) -
Carbonari Dena M.,
Saine M. Elle,
Newcomb Craig W.,
Blak Betina,
Roy Jason A.,
Haynes Kevin,
Wood Jennifer,
Gallagher Arlene M.,
Bhullar Harshvinder,
Cardillo Serena,
Hennessy Sean,
Strom Brian L.,
Lo Re Vincent
Publication year - 2015
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.3844
Subject(s) - saxagliptin , medicine , medical prescription , pharmacy , pharmacoepidemiology , clinical practice , family medicine , pediatrics , pharmacology , metformin , sitagliptin , insulin
Purpose Pharmacoepidemiology researchers often utilize data from two UK electronic medical record databases, the Clinical Practice Research Datalink (CPRD) and The Health Improvement Network (THIN), and may choose to combine the two in an effort to increase sample size. To minimize duplication of data, previous studies examined the practice‐level overlap between these databases. However, the proportion of overlapping patients remains unknown. We developed a method using demographic and pharmacy variables to identify patients included in both CPRD and THIN, and applied this method to measure the proportion of overlapping patients who initiated the oral anti‐diabetic drug saxagliptin. Methods We conducted a cross‐sectional study among patients initiating saxagliptin in CPRD and THIN between October 2009 and September 2012. Within both databases, we identified patients: (i) ≥18 years, (ii) newly prescribed saxagliptin, and (iii) with ≥180 days enrollment prior to saxagliptin initiation. Demographic data (birth year, sex, patient registration date, family number, and marital status) and prescriptions (including dates) for the first two oral anti‐diabetic drugs prescribed within the study period were used to identify matching patients. Results Among 4202 CPRD and 3641 THIN patients initiating saxagliptin, 2574 overlapping patients (61% of CPRD saxagliptin initiators; 71% of THIN saxagliptin initiators) were identified. Among these patients, 2474 patients (96%) perfectly matched on all demographic and prescription data. Conclusions Within each database, over 60% of patients initiating saxagliptin were included within both CPRD and THIN. Combined demographic and prescription data can be used to identify patients included in both CPRD and THIN. Copyright © 2015 John Wiley & Sons, Ltd.