title: Are ECG monitoring recommendations before prescription of QT-prolonging drugs applied in daily practice? The example of haloperidol.
abstract: OBJECTIVE
  Monitoring of the QT duration by electrocardiography (ECG) prior to treatment is frequently recommended in the label of QT-prolonging drugs. It is, however, unknown how often general practitioners in daily clinical practice are adhering to these risk-minimization measures. We assessed the frequency of ECG measurements in patients where haloperidol was initiated in primary care.
  
  
  METHODS
  Patients (≥18 years) with a first prescription of haloperidol in the UK Clinical Practice Research Datalink (2009-2013) were included. The proportion of ECGs made was determined in two blocks of 4 weeks: during the exposure period when haloperidol was initiated, and during the control period, 1 year before. Conditional logistic regression analysis was applied to calculate the relative risk of having an ECG in the exposure period compared with the control period. Subgroup analyses were performed to assess the proportion of ECG measurements in patients with one or more additional risk factors for QT prolongation.
  
  
  RESULTS
  In total, 3420 patients were prescribed haloperidol during the exposure period, and 1.8% of them had an ECG at treatment initiation, compared with 0.8% during the control period (relative risk [RR] 2.4 [1.5-3.8]). Of the patients with additional risk factors for QT prolongation, 1.9% of the patients had an ECG at initiation of the prescription, compared with 1.0% during the control period (RR 2.1 [1.2-3.5]).
  
  
  CONCLUSIONS
  Compliance with recommendations to perform an electrocardiogram when starting a new QT-prolonging drug is extremely low, when haloperidol is taken as an example.
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.|Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Miriam Jacoba
authors.initials: MJ
authors.lastname: Warnier
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Frans Hendrik
authors.initials: FH
authors.lastname: Rutten
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Patrick Cyriel
authors.initials: PC
authors.lastname: Souverein
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Anthonius
authors.initials: A
authors.lastname: de Boer
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Arno Wilhelmus
authors.initials: AW
authors.lastname: Hoes
authors.affiliation: Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Marie Louise
authors.initials: ML
authors.lastname: De Bruin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016903:Drug Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D004562:Electrocardiography; D005260:Female; D006220:Haloperidol / Q000008:administration & dosage*; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012307:Risk Factors; D055815:Young Adult
chemical_list: D006220:Haloperidol
keywords: antipsychotic agent; cardiac arrhythmia; communication; epidemiology; pharmacoepidemiology; regulatory; risk minimization