On July 9, 2018, Health Canada announced a voluntary recall of 6 generic valsartan products due to the detection of a known carcinogen nitrosodimethylamine (NDMA). In total, more than 22 countries, including the United States, initiated recalls. Despite an increase in drug recalls, few studies have evaluated their impact. The valsartan recall, of a frequently used oral medication for high prevalence chronic conditions, such as, hypertension, provides an opportunity to examine the consequences of a drug recall by patients and health care systems.
We used a segmented regression analysis using multiple linked healthcare databases in Ontario, Canada, including the Ontario Drug Benefit (ODB) prescription claims database to identify our cohort of recalled valsartan users and to ascertain non-valsartan medication use, the Ontario Registered Persons database for vital status, Canadian Institute for Health Information for discharge diagnoses for hospital admissions, baseline comorbidities, and clinical outcomes, National Ambulatory Care Reporting System database for emergency department (ED) visits, and Statistics Canada census database for income datasets. These datasets were linked using unique encoded identifiers and analyzed at ICES. We included patients ≥65 years old who had been dispensed a supply of at least one recalled valsartan product that would cover the period up to and including the date of 7/9/2018, and were alive on this date.
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