The document discusses the objectives, approach, and applications of Drug Utilization Studies (DUS) in pharmacotherapy, emphasizing their role in understanding drug use patterns and promoting rational medication practices in society. DUS evaluates qualitative and quantitative aspects of drug use, identifies early signs of irrational use, and facilitates interventions to enhance medication appropriateness. It outlines methodologies for conducting DUS, the types of drugs studied, and the sources of data utilized for informed drug policy and healthcare decisions.

1. OBJECTIVES, APPROACH AND
APPLICATION
OF
DRUG UTILIZATION STUDIES
IN
PHARMACOTHERAPEUTICS
Dr Vedvyas Mishra
2nd Year PGT
1

2. INTRODUCTION
• WHO Definition of DUS:
The study of marketing, distribution, prescription and the use of drugs in a
society with special emphasis on the resulting medical ,social and
economic consequences.
• DUS is a powerful and exploratory tool to document the
role of drugs in the society and thereby creating a sound
sociomedical and health economic basis for regulatory and
other policy decisions.
• 1st initiated in Northern Europe and UK in mid 1960s and
used Antidiabetic drug as an example.
• The scope and influence of DUS has broadened
impressively over the last few years.
2

3. DRUG EVALUATION
The proces of drug evaluation is a composite undertaking
that includes three complementary steps:
1. the asesment of the “BENEFIT"side of the molecule or
product, i.e. the qualitative and quantitative
evaluation of its therapeutic efficacy;
2. the study of the “RISK"side of the drug, both in
controlled trials and under normal conditions of care;
and
3. the evaluation of the “IMPACT” of the drug
treatment(s) on the natural history of disease in
society
3

4. • The questions and paths of DUS can be summarized as
follows:
1. How are drugs used quantitatively and qualitatively in
society?
2. What are the factors that determine the similarities or the
differences in their utilization
– What is the fraction of patients exposed to treatments?
– According to accepted standards?
– According to causal criteria?
– According to schedules that positively differ from those tested
in RCT?
3.Do the pattern of drug use (extension, quality) have any co-
relation with prevalence of side effects(overall or drug
class specific)?
4.What is the impact of different conditions of drug use
(over/under writing) or (wrong prescription) on the
population with respect to (a)Care and Health (b)ADR 4

5. OBJECTIVES
OF
DUS
5

6. The basic questions that utilization studies can answer:
– what happens to drugs when they enter the community??
– what factors influence their continuity??
– what is their effect in the community??
• The principal aim of DUS is to facilitate the rational use of drugs in a
population.
1. Description of drug use pattern
2. Early signals of irrational use of drugs
3. Interventions to improve drug use-follow up
4. Quality control of drug use
• “Patients receive medications appropriate to their clinical needs,
in doses that meet their own individual requirements, for an
adequate period of time, and at the lowest cost to them and their
community” (WHO, 1985)
6

7. DESCRIPTION OF DRUG USE PATTERN
• Drug utilization research will increase our understanding of
how drugs are being used by-
 Estimating the numbers of patients exposed to specified
drugs within a given time period-INCIDENCE OR
PREVELANCE
 Getting extent of use at certain moment &/or in a certain
area.(e.g.country,region,community ,hospital)
BENEFITS-Continous Evaluation System -Patterns are followed
over time and trends in drug use can be described.
7

8.  Estimating to what extent drugs are properly used,
overused or underused.
 Determining pattern or profile of drug use –Alternative
drug use profile.
 Comparing the practiced pattern with the recommended
pattern/guidelines-(Shift from Experience based practice
to Evidence based Medicine )
 Feeding back of the drug utilization data to prescribers.
 Assessing the potential magnitude of the problem-
Relating no of case reports about a drug problem or
adverse effects to the number of patients exposed.
8

9. EARLY SIGNALS OF IRRATIONAL USE OF DRUGS
 Comparing drug utilization patterns and cost between
different regions or time period.
o Differences-Hypothesis formed.
o Useful investigations having medical, social & economic
implications both for the individual patients and for the
society.
 Comparing observed patterns of drug use with current
recommendation or guidelines for the treatment of
certain disease .
o Pedagogic interventions??
o Reviewing guidelines??
Include both overuse and underuse of drugs.
9

10. INTERVENTIONS TO IMPROVE DRUG USE- FOLLOW UP
• Drug utilization research may enable us to assess whether
interventions undertaken to improve drug use have had the
desired impact by:
• Monitoring and evaluating the effects of measures
taken to improve undesirable patterns of drug
use(regional or local formularies, information
campaigns, regulatory policies etc..)
• Following the impact of regulatory changes or changes
in the insurance or reimbursement schemes-Negative
or Positive??
• Promotional activities of the pharmaceutical industry
and educational activities of the society impact on the
patterns of drug use-EXTENT?? 10

11. QUALITY CONTROL OF DRUG USE
11

12. • Drug use should be controlled according to a quality
control cycle that offers a systematic framework for
continuous quality improvement.
• Application at many levels :Local or Regional discussion
groups consisting of Physicians,Clinical
Pharmacologist/Pharmacist to National /International
initiatives.
• BENCHMARKING by comparing drug utilization data
from different localities –Differences which may
require further evaluation-Identification and
Promotion of best practices.
12

13. STEPS IN CONDUCTING A DUS:
Identify drugs or therapeutic areas of practice for
inclusion in the program
Design of study
Define criteria and standards
 Design the data collection form
Data collection
Evaluate the results
Provide feedback of results
Develop and implement interventions
Re-evaluate to determine if drug use has improved
Reassess and revise the DUS prog
Feedback results
13

14. TARGETS OF DUS
Can be targeted towards any of following links in drug-use
chain:
1.SYSTEMS & STRUCTURES surrounding drug use(eg-how
drugs are ordered, delivered & administered in a
hospital or other facility)
2.PROCESSES of drug use (eg what drugs are used & how
they are used and does their use comply with the
relevant criteria, guidelines or restrictions)
3.OUTCOMES of drug use(eg..efficacy, ADRs & the use of
resources such as drugs, laboratory tests ,hospital beds
or procedures)
14

15. TARGETS OF DUS(CONTD...)
• Generally drugs with a high volume of use,
high cost or high frequency of adverse drug
reactions are subjected to DU studies.
o Commonly prescribed drugs e.g. Antibiotics, PPIs,
etc.
o Drugs with significant drug interactions e.g.
Warfarin, Phenytoin
o Expensive drugs e.g. LMWH, Cephalosporins
o Newer drugs
o Drugs with a narrow therapeutic index e.g.
Digoxin, Theophylline, Lithium
o Drugs with serious ADRs e.g. aminoglycoside,
NSAIDs etc.
15

16. TYPES OF DRUG USE INFORMATION
• DRUG BASED INFORMATION
• PROBLEM OR ENCOUNTER BASED
INFORMATION
• PATIENT BASED INFORMATION
• PRESCRIBER BASED INFORMATION
• COST BASED INFORMATION
16

17. DRUG BASED INFORMATION
Data on drug use on various levels, and information
on indications, doses and dosage regimen is
usually necessary
Indication –
– For drugs with multiple indications, it will usually
be important to divide data on use according to
indication to allow a correct interpretation of the
overall trends.
• E.g.-Aspirin, Beta Blocker
17

18. PROBLEM/ ENCOUNTER BASED INFORMATION
How a particular problem(HTN,sore
throat,Depression) is managed??.
E.g.
– Does the severity of the disease influence the
choice of single or combination therapy ?
– Is the management of newly-presenting patients
different to that of patients already receiving
treatment ?
– Are there likely to be any drug interactions with
co-prescribed treatments ?
– Is the choice of drug influenced by evidence based
outcome data ?
18

19. PATIENT INFORMATION
• Information on demographic factors and other
details about the patient are useful
– Age distribution
– Co-morbidities of patient
– Knowledge, beliefs and perceptions of patients
and their attitudes to drugs are important.
COST BASED INFORMATION
• Managing policy related to drug supply,
pricing and use.
19

20. PRESCRIBER INFORMATION
• It is claimed that doctors differ more than patients and that
difference in drug prescribing often lack rational explanations.
• Are prescribing profiles influenced by the prescriber’s medical
education?
• Do the prescribing profiles of specialists differ from those of
general practitioners ?
• Does the age or gender of the prescriber influence the prescribing
profile ?
• Are there differences in prescribing behaviour between urban and
rural practices or between small and large practices ?
• Who are those prescribers who rapidly adopt to recently released
drugs ?
• Can the factors that determine and change prescribing behavior
be identified ?
20

21. TYPES OF DUS
• DUS are largely of 2 types:
QUANTITATIVE QUALITATIVE
According to the manner and duration of collection of
data (either quantitative or qualitative studies) can be
further classified as:
a)CROSS SECTIONAL STUDY
b) LONGITUDNAL STUDY
c)CONTINOUS LONGITUDNAL STUDY 21

22. • QUANTITATIVE:-
• Used to describe present situation and the trends
in the drug prescription and drug use at various
levels of the health care system.
• Quantitative data may be routinely collected
data or obtained from surveys.
• QUALITATIVE:-
• Assess the appropriateness of drug utilization and
link the prescribing data to reasons for
prescribing.
• DUE
• Therapeutic/prescription audit.
22

23. • CROSS SECTIONAL STUDIES-
– Provide a snapshot of drug use at a particular time like
over a year, a month or a day
– Used for making comparisons with similar data
collected over the same period in a different country,
health facility or a ward.
– Can be carried out before and after an intervention
– Studies can simply measure drug use or can be utilized
to assess drug use in relation to guidelines or
restrictions.
• LONGITUDINAL STUDIES-
– An observational research method in which data is
gathered repeatedly over a period of time.
– Longitudinal research projects can extend over years
or even decades.
23

24. – Often obtained from repeated cross sectional surveys.
– Data collection is continuous but the practitioner
surveyed and therefore patients are continuously
changing.
– Such data gives information about overall trends but
not about prescribing trends.
• CONTINUOUS LONGITUDINAL STUDY-
– Data collected at the level of individual practitioner
and patient level.
– This data can address a range of issues including
reasons for change in therapy, adverse effects and
health outcomes
24

25. QUALITATIVE STUDY:DUE/DUR
• Drug utilization evaluation (DUE) defined as an
authorized, structured, ongoing review of physician
prescribing, pharmacist dispensing and patient using
medication.
• Systematic process designed to maintain the
appropriate and effective use of drugs.
• TYPES
• OBJECTIVES OF DUE:-
– To ensure that drug therapy meets current standards of
care
– To control drug costs
– To prevent problem related to medication, ADRs
– To evaluate effectiveness of drug therapy
– To identify areas of practice that require further education
of practitioners. 25

26. PROSPECTIVE DUE
– Involves evaluating a patient’s planned drug
therapy before a medication is dispensed.
– Pharmacists perform prospective reviews by
assessing prescription medication’s dosage and it’s
directions and reviewing patient information for
possible drug interactions or duplication of
therapy
• Pros-DUE addresses drug-disease
contraindication, therapeutic interchange,
generic substitution, incorrect drug dosage,
inappropriate duration of t/t, drug allergy
interaction and clinical abuse/misuse. 26

27. 1
• CONCURRENT DUE:
• Performed during the course of treatment and involves
ongoing monitoring of drug therapy to ensure positive
patient outcomes.
• Typical criteria reviewed:-
– Drug-drug interactions
– High or low dosages
– Duplicate therapy
– Drug-disease interaction
– Over and under utilization
– Drug-age precautions
– Drug-gender precautions
– Drug-pregnancy precaution
27

28. RETROSPECTIVE DUE
• Simplest to perform since drug therapy is reviewed
after the patient has received medication.
• Patients medical chart or computerized records are
screened to determine whether the drug therapy met
approved criteria individually as well as in group of
patients(HTN,DM).
• It commonly addresses the issues like therapeutic
appropriateness, over and under utilization
,Appropriate generic use ,Therapeutic duplication,
drug disease contraindication, drug disease
interactions, incorrect drug dosage, clinical
abuse/misuse.
28

29. SOURCE OF DATA
LARGE DATABASES
DATA FROM DRUG REGULATORY
AGENCY
SUPPLIER (DISTRIBUTION) DATA
PRACTICE SETTING DATA
COMMUNITY SETTING DATA
29

30. LARGE DATABASES
• Data-Drug sales ,drug movement at various levels of drug
distribution chain, pharmaceutical and medical billing or
samples of prescription.
• May be international, national or local------- comparative
studies can be planned at various levels.
• May be diagnosis linked or non-diagnosis linked
• Diagnosis linked data enable drug use to be analyzed
according to patients characteristics, therapeutic groups,
diseases or conditions and, clinical outcome.
30

31. DATA FROM DRUG REGULATORY AGENCIES:-
• Agencies have the legal responsibility of ensuring the
availability of safe, efficacious and good quality drugs in their
country.
• Are repositories of data on which drugs have been registered
for use, withdrawn or banned within a country.
• Possible to obtain data on the number of drugs registered in a
country from such agencies.
• Importation data like product type (i.e. generic or branded),
volume, port of origin, country of manufacture, batch number
and expiry date may be collected.
• LIMITATION
31

32. SUPPLIER (DISTRIBUTION) DATA
• Wholesalers-linking point b/w manufacturer and consumer.
• Data on Supplier –obtained from drug importer or local
manufacturer or appropriate govt agencies.
• Reliable-Legal entity
COMMUNITY SETTING DATA
• Drugs available in households -prescribed or dispensed at
health facilities, purchased at pharmacy(w or w/o
prescription) or OTC.
• Current or Previous illness-Good or Poor adherance
• Mismatched Dispensing and Utilization data
• OPD/IPD
32

33. PRACTICE SETTING DATA
• Generate indicators that provide information on
prescribing habits and aspects of patient care.
–PRESCRIBING DATA
–DISPENSING DATA
–AGGREGATE (FACILITY) DATA
–OVER-THE-COUNTER AND PHARMACIST-
PRESCRIBED DRUGS
–TELEPHONE AND INTERNET PRESCRIBING
33

34. • PRESCRIBING DATA:
• Usually extracted from OPD/IPD prescriptions.
• Information that may be obtained from
prescriptions includes
oPatient’s demography
oDrug name, dosage form, strength, dose, frequency of
administration and duration of treatment.
oWhere diagnoses are noted on prescriptions, is possible
to link drug use to indications.(Under/Over use).
oTrends in utilization for specific drugs and diseases can
also be established.
oAnalyze the difference between DDD & PDD if any
34

35. DISPENSING DATA:-
• Drug dispensing is a process that ends with a client
leaving a drug outlet with a defined quantity of
medication and instructions for using it.
– Information available from dispensers may include
oDrug (s) prescribed
oAverage number of items per prescription
oPercentage of items prescribed that were actually
supplied(avaibility)
oPercentage of drugs adequately labeled
oQuantity of medications dispensed
oCost of each item or prescription.
35

36. • AGGREGATE DATA
• SOURCE include – pharmacy stock and dispensing records,
medication error records, adverse drug reaction records
and patient medical records.
• Used to obtain information on
oThe cost of individual drugs and classes of drug
oThe most and least expensive drugs
oThe per capita consumption of specific products.
oThe prevalence of adverse drug reactions.
oThe prevalence of medication errors.
oThe percentage of the budget spent on specific drugs
or classes of drug.
• These data are useful for utilization of a particular drug to that
of other drug and to utilization in other hospitals , regions or
countries.
36

37. OVER-THE-COUNTER AND PHARMACIST-PRESCRIBED
DRUGS:
• No prescription required.
• Data difficult to obtain.
TELEPHONE AND INTERNET PRESCRIBING:
• Mostly in developed countries—Nutritional
/Herbal supplements.
• Innovative ways need to be devised to collect
information on this type of transaction.
37

38. DESCRIPTIVE TOOLS & ANALYSIS FOR
DRUG EVALUATION STUDIES
• WHO has developed certain standardized objective
measures & indicators
• Help in quantifying & describing the appropriateness of
pharmaceutical care in a country, region or individual
facility
• Some of the measures are as follows:
WHO’S DRUG USE INDICATORS
DRUG CLASSIFICATION SYSTEMS
DEFINED DAILY DOSE
38

39. WHO DRUG USE INDICATORS/CORE INDICATORS
• It measure specific aspects of the behaviour of
health providers in health facilities in a
reproducible manner, irrespective of who
measures them or when the measures are taken.
• Measures of performance in 3 general areas
related to rational use of drugs
1.pharmaceutical prescribing practices by health providers
2.key elements of patient care, taking into consideration both,
aspects of clinical consultation & pharmaceutical
dispensing
3.Facility specific factors such as key essential drugs &
minimum pharmaceutical information
39

40. • CORE DRUG USE INDICATORS
• PRESCRIBING INDICATORS
o Average number of drugs per encounter
o Percentage of drugs prescribed by generic name
o Percentage of encounters with an antibiotic prescribed
o Percentage of encounters with an injection prescribed
o Percentage of drugs prescribed from EDL or formulary
• PATIENT CARE INDICATORS
o Average consultation time
o Average dispensing time
o Percentage of drugs actually dispensed
o Percentage of drugs adequately labelled
o Patients' knowledge of correct dosage
• FACILITY INDICATORS
o Availability of copy of essential drugs list or formulary
o Availability of key drugs
o Availability of clinical guidelines
40

41. • COMPLEMENTARY DRUG USE INDICATORS
o Average medicine cost per encounter.
o Percentage prescriptions in accordance with
clinical guidelines.
o Percentage of patients treated without drugs.
o Percentage of drug cost spent on antibiotics.
o Percentage of patients satisfied with the care
they received.
o Percentage of health facilities with access to
impartial drug information.
41

42. DRUG CLASSIFICATION SYSTEM
• The main purpose of having an international
standard is to be able to compare data between
countries.
• Different classification systems : -
i. ATC classification develop by Norwegian
researchers.
ii. AT classification developed by the European
Pharmaceutical Market Research Association
(EPhMRA)
– The EPhMRA classification system is used worldwide
by IMS for providing market research statistics to the
pharmaceutical industry
• Lmt-FDC
42

43. DEFINED DAILY DOSE
• The DDD is the assumed average maintenance dose per
day for a drug used for its main indication in adults.
• DDD is a unit of measurement----different from PDD
• Seldom prescribed because it is an average of two or more
commonly used dosed sizes
• Doses for individual patients and patient groups will often
differ from the DDD as they must be based on individual
characteristics (e.g. age and weight) and pharmacokinetic
considerations.
• DDD system most frequently used in academic articles &
reports & as a tool for comparison and control over
nationwide total drug consumption
43

44. • It give a rough estimate of consumption and not
an exact picture of actual use.
• DDDs provide a fixed unit of measurement
independent of price, currency, package size and
strength enabling the researcher to assess trends
in drug consumption and to perform comparisons
between population groups.
• Drug utilization figures should ideally be
presented as numbers of DDDs per 1000
inhabitants per day or, when drug use by
inpatients is considered, as DDDs per 100 bed-
days.
44

45. • DDDs are not established for:-
oTopical products
oSera, vaccines
oAntineoplastic agents
oAllergen extracts
oGeneral and Local anesthetics
oContrast media
PDD
● Gives the average daily amount of a drug that is actually
prescribed
● The PDD can vary according to both the illness treated and
the national therapeutic traditions.
● PDD does not necessarily reflect actual drug utilization.
45

46. STATISTICAL APPLICATION IN DRUG
UTILIZATION RESEARCH
• Statistical Package for social science (SPSS) can
be used.
• Chi square test can be used to test the
difference between the proportions.
46

47. FUTURE PERSPECTIVES:
• The study of drug utilization in an evolving field.
• The use of large computerized databases that
allow linkage of drug utilization data to diagnosis,
subject to some inherent limitations, is
contributing to expand this area of study.
• Importance of drug utilization studies in
pharmacoepidemiology has been increasing due
to their close association to other areas like-
public health, pharmacovigilance ,
pharmacoeconomics and pharmacogenetics.
47

48. CONCLUSION
• Successful research in drug utilization requires
multidisciplinary collaboration between clinicians,
clinical pharmacologists, pharmacists and
epidemiologists.
• Without the support of the prescribers, this research
effort will fail to reach its goal of facilitating the
rational use of drugs.
• Only by a combination of regulatory, informative and
educational actions, together with a general
improvement of the quality of in and out-patient
medical care in the National Health System, the use of
drugs can be more rational.
48

49. 49