title: Drug allergies documented in electronic health records of a large healthcare system.
abstract: The prevalence of drug allergies documented in electronic health records (EHRs) of large patient populations is understudied.
  
  
  
  We aimed to describe the prevalence of common drug allergies and patient characteristics documented in EHRs of a large healthcare network over the last two decades.
  
  
  
  Drug allergy data were obtained from EHRs of patients who visited two large tertiary care hospitals in Boston from 1990 to 2013. The prevalence of each drug and drug class was calculated and compared by sex and race/ethnicity. The number of allergies per patient was calculated and the frequency of patients having 1, 2, 3…, or 10+ drug allergies was reported. We also conducted a trend analysis by comparing the proportion of each allergy to the total number of drug allergies over time.
  
  
  
  Among 1 766 328 patients, 35.5% of patients had at least one reported drug allergy with an average of 1.95 drug allergies per patient. The most commonly reported drug allergies in this population were to penicillins (12.8%), sulfonamide antibiotics (7.4%), opiates (6.8%), and nonsteroidal anti-inflammatory drugs (NSAIDs) (3.5%). The relative proportion of allergies to angiotensin-converting enzyme (ACE) inhibitors and HMG CoA reductase inhibitors (statins) have more than doubled since early 2000s. Drug allergies were most prevalent among females and white patients except for NSAIDs, ACE inhibitors, and thiazide diuretics, which were more prevalent in black patients.
  
  
  
  Females and white patients may be more likely to experience a reaction from common medications. An increase in reported allergies to ACE inhibitors and statins is noteworthy.
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital, Boston, MA, USA.|Clinical Informatics, Partners eCare, Partners HealthCare System, Boston, MA, USA.|Harvard Medical School, Boston, MA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Dhopeshwarkar
authors.affiliation: Allergy and Immunology, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: K G
authors.initials: KG
authors.lastname: Blumenthal
authors.affiliation: Department of Emergency Medicine, University of Colorado, Aurora, CO, USA.
authors.forename: F
authors.initials: F
authors.lastname: Goss
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital, Boston, MA, USA.|Harvard Medical School, Boston, MA, USA.
authors.forename: M
authors.initials: M
authors.lastname: Topaz
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital, Boston, MA, USA.|Division of Pharmacy, School of Medicine, Pharmacy and Health, Durham University, Durham, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Slight
authors.affiliation: Division of General Internal Medicine and Primary Care, Brigham and Women's Hospital, Boston, MA, USA.|Harvard Medical School, Boston, MA, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Bates
mesh_terms: D016208:Databases, Factual; D004342:Drug Hypersensitivity / Q000453:epidemiology*; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts / Q000453:epidemiology / Q000208:ethnology; D004364:Pharmaceutical Preparations / Q000145:classification; D011159:Population Surveillance; D015995:Prevalence
chemical_list: D004364:Pharmaceutical Preparations
keywords: adverse drug event; drug allergy; drug hypersensitivity; electronic health records; safety