Pharmacoepidemiology in Pharmacy Practice

1
Pharmacoepidemiology in Pharmacy Practice
2

• This chapter discusses the incorporation of
  evidence-based medicine into clinical practice.
• Other areas to which pharmacists apply
  pharmacoepidemiological methods include
• adverse drug reaction surveillance
• drug utilization evaluations (DUEs)
• pharmacoeconomical analyses
• All of these functions provide pharmacists with
  excellent sources of data to conduct more
  formalized pharmacoepidemiological research.

3
Evidence-Based Medicine

• The best drug therapy decisions are decisions
  based on sound evidence.
• Evidence that a drug is safe and effective is
  obtained from pharmacoepidemiological studies and
  disseminated via the medical literature.
• Medical literature can be classified as
• primary
• secondary
• tertiary

4
Primary medical literature

• Provides new information to the field of medicine
  and consists of
• descriptive
• observational
• interventional studies.
• All of these study designs are used to provide
  new information about the use or effect of a
  particular drug in a specific population.
• These studies are then published in pharmacy and
  medical journals.
• Hundreds of medical journals are published every
  week.

5
Secondary medical literature

• Consists of indexing systems.
• The secondary systems allow practitioners to
  search through the vast array of medical journals
  to find information about a particular subject.
• Some databases provide access to complete
  article(s), and others provide information only
  on where to locate the article(s).
• Example The Medline database, (PubMed)
• most commonly used
• was created in 1966
• indexes more than 1600 medical journals

6
Tertiary medical literature

• Consists of literature reviews, which can be in
  the form of
• textbooks
• reference books
• review articles in medical journals.
• Before a review is written
• a literature search is conducted using the
  secondary systems to identify all of the articles
  published on a particular subject.
• The information is then collated and presented in
  a manner that is easily used by practitioners.
• Tertiary resources are quick, efficient resources
  that are used to answer questions about the most
  common clinical problems.

7

• Suppose a patient presents to a clinician
  complaining of tachycardia.
• The clinician conducts
• a complete medical history
• physical examination of the patient.
• If the clinician suspects the tachycardia is an
  adverse drug reaction associated with a
  particular medication, then he or she attempts to
  find evidence in the literature that supports the
  suspicion.
• The best clinical decisions are based on sound
  medical evidence, rather than hunches or
  suspicions.

8

• To obtain medical evidence on a particular topic,
  clinicians
• first searches the tertiary literature (e.g.,
  textbooks, reference books).
• If no information is found, a literature search
  using the secondary systems is conducted.
• A literature search reveals where and when
  information on the topic has been published
• The clinician must then retrieve and review all
  of the articles.
• The studies must be critiqued with regard to
  design, methodology, quality of data, and bias.
• A clinical decision based on sound evidence is
  then made that either supports or negates the
  theory that the tachycardia is associated with
  the use of the drug.

9
Cochrane Database of Systematic Reviews.

• Archie Cochrane, a physician-epidemiologist,
  realized that conducting exhaustive literature
  searches and medical literature reviews were
  daunting and time-consuming tasks requiring many
  resources.
• Cochrane believed that clinicians should be able
  to conduct a search on a specific topic and find
  a well-conducted, systematic review that
  identifies and summarizes all of the medical
  literature published on a particular topic.
• He enlisted a group of international
  collaborators to create and maintain such a
  database it is called the Cochrane Database of
  Systematic Reviews.

10

• They have included reviews on
• herbal medicine
• Homeopathy alternative medicine, treats patients
  with heavily diluted preparations
• acupuncture
• massage
• Cochrane collaborators perform exhaustive
  searches for published and unpublished studies in
  English and other languages.

11

• Whenever possible, the Cochrane reviews are based
  on
• randomized clinical trials (the gold standard in
  medical research.)
• If randomized clinical trials are not available,
  then the strongest observational studiesthe best
  designed and conducted studiesare used in the
  Cochrane reviews.
• After completion, the reviews undergo rigorous
  peer review.
• Cochrane reviews are updated on a regular basis
  to include new information.

12
Adverse Drug Reaction Surveillance

• Adverse drug reaction reporting and monitoring
  plays an important role in the postmarketing
  surveillance of drugs.
• Pharmacists play an integral part in adverse drug
  reaction reporting.
• In fact, historically, pharmacists have the
  highest rate of adverse drug reaction reporting
  among health care professionals.

13

• Typically, pharmacists collect and report adverse
  drug reactions on a regular basis to pharmacy and
  therapeutics committees (PT committees) in their
  individual institution.
• These reports are most commonly used to monitor
  the safety of drugs within institutions, but
  pharmacists are usually also responsible for
  forwarding serious adverse drug reactions to the
  Food and Drug Administration (FDA).
• Just as the FDA acts after receiving several
  serious adverse drug reactions associated with a
  particular drug, the PT committees of individual
  institutions react to serious adverse drug
  reactions within the institution by creating
  medication guidelines and restrictions.

14
Drug Utilization Studies

• The World Health Organization (WHO) defines drug
  utilization as "the marketing, distribution,
  prescription, and use of drugs in a society, with
  special emphasis on the resulting medical,
  social, and economic consequences.''
• Pharmacists conduct drug utilization studies, or
  DUEs, as part of their routine activities.
• Like adverse drug reaction monitoring, the Joint
  Commission for the Accreditation of Health Care
  Organizations (JCAHO) requires health care
  institutions to conduct drug utilization studies.

15

• DUEs are most commonly conducted to monitor
  prescribing patterns.
• Medications monitored via DUE are chosen
  according to
• cost
• frequency of use
• risk of toxicity.
• Drugs newly approved by the FDA that have shown
  serious adverse effects in phase III trials are
  typically chosen to be monitored via DUEs.

16

• Example
• when alteplase (TPA ) was first approved by the
  FDA, many practitioners were concerned about the
  bleeding side effects that had occurred in phase
  III trials.
• Consequently, pharmacists chose to conduct DUEs
  to monitor the use of alteplase.
• Information was collected on both prescribers and
  patients.
• Data collected on patients included
• demographic information
• past medical history
• Indication
• Dose
• duration of therapy
• specific documentation of unintended bleeding
  effects.
• The goal of the DUEs was to monitor the use of
  alteplase to ensure that the drug was being used
  as indicated in the proper patients and to
  measure the extent of bleeding associated with
  alteplase.

17

• Subjects exposed to a particular drug are
  followed for a period to determine the incidence
  of an adverse reaction.
• These DUEs can easily be expanded to a
  prospective cohort model.

18
Pharmacoepidemiological Research as an Extension
of Daily Clinical Practice

• Pharmacists in clinical settings monitor the uses
  and effects of drugs on a daily basis.
• Clinical pharmacists collect information about
  individual patients however, pharmacists can
  also choose to view patients as populations,
  rather than individuals, for the purpose of
  epidemiological research.
• If information collected about patients is
  systematic and routine, then the routine
  monitoring of individual patients can easily be
  applied to a cohort study design.
• The data collected can then be analyzed to
  generate new hypotheses or to identify trends of
  drug use.

19

• For example, a pharmacist conducting rounds in a
  critical care unit will collect information about
  individual patients with regard to demographics,
  past medical history, current medical problems,
  laboratory data, physical findings, and so forth.
  
• The pharmacist will monitor each individual
  patient in an effort to optimize pharmaceutical
  care.
• The data collection may or may not be consistent
  from patient to patient.
• In this scenario, the information is typically
  used solely for the purpose of caring for the
  patient.

20

• The pharmacist could instead choose to develop
  data-collection forms to be used on all patients.
  
• If data collection is systematic and consistent,
  then the data can be analyzed to determine the
  effects of drugs within populations of patients,
  rather than thinking of patients only as
  individuals.
• New hypotheses can be generated from the data
  collection and analysis these hypotheses can
  then be tested using more sophisticated
  observational or interventional studies.

21
Professional Organizations and Journals in Epidemiology
Professional organizations  
  American College of Epidemiology
  American Public Health Association
  American Statistical Association, Section on Epidemiology
  Association for Professionals in Infection Control Epidemiology
  Canadian Society for Epidemiology and Biostatistics
  European Society of Clinical Pharmacy
  International Society for Pharmacoepidemiology
  Society for Epidemiologic Research
22
Professional journals  
  American Journal of Epidemiology  
  American Journal of Public Health  
  Annals of Epidemiology  
  Biometrics  
  Drug Safety  
  Emerging Infectious Diseases  
  Epidemiologic Reviews  
  Epidemiology  
  Epidemiology and Infection  
  Journal of Clinical Epidemiology  
  Journal of Epidemiology and Community Health  
  MMWR Morbidity and Mortality Weekly Report  
  Pharmacoepidemiology and Drug Safety  
  Society for Clinical Trials  
  Viral and Health Statistics  
  Weekly Epidemiological Record  
  World Health Statistics Quarterly  
23
E-mail/Web Address Type of Site
  List serves  
E-mail address LISTPROC_at_CC.UMONTREAL.CA. To subscribe, include "subscribe epidemio-1 your first and last names" in the body of the message.   Epidemiology Discussion Group
E-mail address majordomo_at_mailhost.tcs.tulane.edu. To subscribe, include "subscribe epi-info end" in the body of the message.   Epi Info Discussion Group
E-mail address LISTSERV_at_UNIVSCVM.CSD.SC.EDU. To subscribe, include "sub epiworld your first and last names" in the body of the message.   EPIWORLD Discussion Group
Web address http//www.egroups.com/group/pharmacoepidemiology.   Pharmacoepidemiology  Pharmacoeconomics Discussion Group
  Epidemiology directory  
http//www.epibiostat.ucsf.edu/epidem/epidem.html   Virtual Library-Epidemiology
  Downloadable Statistical Software  
http//www.cdc.gov/epiinfo   Epi Info