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Drug Utilization Studies 
Dr. Mansij Biswas, SYR 
Department of Pharmacology & Therapeutics 
Seth G S Medical College & KE...
Introduction & Definition: 
 Pharmaco-epidemiology is the study of use and effects 
or side-effects of drugs in large num...
Looking back… 
 Initiated in Northern Europe and The UK in the mid 
1960s 
 Arthur Engel in Sweden and Pieter Siderius i...
 Constitution of WHO European Drug Utilization 
Research Group (DURG) 
 Development of a new unit of measurement, initia...
Why drug utilization research? 
 The principal aim is to facilitate the rational use of 
drugs in populations. 
 Rationa...
Objectives: 
 Description of drug use pattern 
 Early signals of irrational use of drugs 
 Interventions to improve dru...
 Description of drug use pattern : - 
Drug utilization research will increase our understanding of 
how drugs are being u...
 Determining pattern or profile of drug use and the 
extent to which alternative drugs are being used to 
treat particula...
 Early signals of irrational use of drugs: 
 Comparing drug utilization patterns and cost 
between different regions or ...
 Interventions to improve drug use-follow 
up: 
 Monitoring and evaluating the effects of measures 
taken to improve und...
 Quality control of drug use: 
Drug use should be controlled according to a quality control 
cycle that offers a systemat...
Types of drug use information 
 Drug based information 
 Problem or encounter based information 
 Patient based informa...
A) Drug based informations 
◦ Data on drug use on various levels, and 
information on indications, doses and dosage 
regim...
 Indication – 
◦ For drugs with multiple indications, it will 
usually be important to divide data on use 
according to i...
B) Problem based informations 
◦ Useful to address the question – how a particular 
problem is managed. 
 Questions that ...
C) Patient based informations 
Information on demographic factors and other 
details about the patient are useful 
Age di...
D) Prescriber based informations 
This information is useful to understand how 
and why drugs are prescribed. 
◦ Some ques...
 Are there differences in prescribing behavior 
between urban and rural practices or between 
small and large practices ?...
E) Cost based informations 
It will always be important in managing policy 
related to drug supply, pricing and use. 
E.g....
The DUS cycle: 
Planning 
Data 
collection 
Evaluation 
Feedback of 
results 
Feedback of 
results 
Interventions 
June 7t...
Steps involved in 
conducting a drug 
utilization study:- 
June 7th, 2014 21
Step 1:- Identify drugs or therapeutic 
areas of practice for inclusion in the 
program 
Drug-use Chain 
a) The systems an...
c) The outcome of drug use 
 e.g. efficacy, adverse drug reactions and the use of 
resources such as drugs, laboratory te...
 Generally drugs with a high volume of use, high cost or 
high frequency of adverse drug reactions are subjected to 
DU s...
Step 2:- Design of study 
In designing the DU study, observational research methods 
are more commonly used. 
 Accordingl...
 Quantitative:- 
Used to describe present situation and the trends in the 
drug prescription and drug use at various leve...
Cross sectional studies- 
 Provide a snapshot of drug use at a particular time like 
over a year, a month or a day 
 Use...
Longitudinal studies- 
 Data can be on total drug use or on a statistically valid 
samples from pharmacies or medical pra...
Continuous longitudinal study- 
◦ This data can address a range of issues 
including reasons for change in therapy, 
adver...
Step 3:- Define criteria and 
standards 
 With an exhaustive literature search, identify the 
key literature in the chose...
Step 4:- Design the data collection form 
 It is impossible to address all aspects of use for each 
◦ Patient demographic...
Step 5:- Data collection 
 Physicians, pharmacists and nurses make 
ideal data collectors. 
 Different types of drug use...
Source of data 
◦ Large databases 
◦ Data from drug regulatory agency 
◦ Supplier (distribution) data 
◦ Practice setting ...
Large databases:- 
◦ Efficient use of health care resources - Computer 
databases or medical record sections 
◦ May be int...
Data from drug regulatory agencies:- 
 Are repositories of data on which drugs have been 
registered for use, withdrawn o...
Supplier (distribution) data:- 
 Drug importation; local manufacture; customs 
service, whole salers 
 In countries wher...
Practice setting data:- 
Generate indicators that provide information on 
prescribing habits and aspects of patient care. ...
 Prescribing data: 
◦ Usually extracted from outpatient and inpatient 
prescriptions. 
◦ Information that may be obtained...
 Dispensing data:- 
Drug dispensing is a process that ends with a client 
leaving a drug outlet with a defined quantity o...
 Aggregate data 
◦ Source include – pharmacy stock and dispensing 
records, medication error records, adverse drug reacti...
 Over-the-counter and pharmacist-prescribed 
drugs: 
◦ Pharmacists and other drug outlet managers may 
prescribe over the...
 Telephone and Internet prescribing: 
 Mostly in developed countries. 
 Innovative ways need to be devised to collect 
...
 Community setting data:- 
 Drugs available in households have either been 
prescribed or dispensed at health facilities...
Step 6:- Evaluate results 
Data evaluation is the most critical step in a DUS 
 Summarize data into the major categories ...
 Reasons for deviation may include: 
◦ Drug being used for new indication 
◦ Outdated procedures 
◦ Inadequate resources ...
Drug utilization metrics include:- 
 Defined daily dose 
 Prescribed daily dose 
 Other units for presentation of volum...
Defined daily dose (DDD):- 
The DDD is the assumed average maintenance dose per 
day for a drug used for its main indicati...
 It give a rough estimate of consumption and not an exact 
picture of actual use. 
 DDDs provide a fixed unit of measure...
 DDDs per 1000 inhabitants per day:- 
◦ Provide a rough estimate of the proportion of the 
study population treated daily...
 DDDs per inhabitant per year:- 
◦ Estimate of the average number of days for which 
each inhabitant is treated annually ...
 DDDs are not established for:- 
◦ Topical products 
◦ Sera, vaccines 
◦ Antineoplastic agents 
◦ Allergen extracts 
◦ Ge...
Prescribed daily dose (PDD):- 
 The prescribed daily dose (PDD) is defined as the 
average dose prescribed according to a...
 The PDD can vary according to both the illness treated 
and the national therapeutic traditions. 
 The PDDs differ: 
◦ ...
 PDD does not necessarily reflect actual drug 
utilization. 
 Specially designed studies including patient 
interviews a...
Other units for presentation of volume: 
These units can be applied only when the use of a single 
drug or of well defined...
 Number of tablets:- 
◦ Counting numbers of tablets does not reflect the 
variations in strengths of tablets, with the re...
Cost:- 
◦ Cost figures are suitable for an overall analysis of 
expenditure on drugs. 
◦ International comparisons based o...
Drug Use Indicators:- 
 Prescribing indicators 
◦ Average number of drugs per encounter 
◦ Percentage of drugs prescribed...
 Patient care indicators 
◦ Average consultation time 
◦ Average dispensing time 
◦ Percentage of drugs actually dispense...
 Complementary drug use indicators 
o Average medicine cost per encounter 
o Percentage prescriptions in accordance with ...
Prescribing indicators:- 
1. Average number of drugs per encounter 
total number of different drug products prescribed 
Av...
3. Percentage of encounters with an antibiotic prescribed 
4. Percentage of encounters with an injection prescribed 
Numbe...
5. Percentage of drugs prescribed from essential drugs list 
or formulary 
The number of products prescribed which are lis...
Patient care indicators:- 
1. Average consultation time 
Total time for a series of consultation 
Average=----------------...
3. Percentage of drugs actually dispensed 
number of drugs actually dispensed 
at the health facility × 100 
%= ----------...
5. Patients' knowledge of correct dosage 
 To reliably evaluate the correctness of patients' 
responses about when they a...
Facility indicators:- 
1. Availability of copy of essential drugs list or formulary 
2. Availability of clinical guideline...
Model list of Key Drugs for testing drug 
availability:- 
Diarrhoea oral rehydration salts 
cotrimoxazole tablets 
Acute r...
Drug classification system:- 
 The main purpose of having an 
international standard is to be able to 
compare data betwe...
◦ Anatomical Therapeutic (AT) classification developed by 
the European Pharmaceutical Market Research 
Association (EPhMR...
Step 7:- Provide feedback of results 
 Prepare a scientific interpretation of the results 
rather than a value judgment. ...
Step 8:- Develop and implement 
interventions 
 If a drug use problem is identified the next step is to 
consider how the...
Step 9:- Re-evaluate to determine 
if drug use has improved 
 Drug use and prescribing patterns need to be 
monitored to ...
Step 10:- Re-assess and revise the 
DUS program 
Results of the previous DU studies help to 
improve quality, efficacy and...
Step 11:- Feedback results 
 Circulate results of the DUS 
 Obtain opinions about success of interventions 
and improvem...
DU 90% 
 Reflects the number of drugs that account for 90% of 
drug prescriptions and adherence to local or national 
pre...
Drug utilization evaluation 
 Drug utilization evaluation (DUE) is defined as an 
authorized, structured, ongoing review ...
Objectives of DUE:- 
 To ensure that drug therapy meets current 
standards of care 
 To control drug costs 
 To prevent...
Classification of DUE: 
A) Prospective DUE:- 
◦ Involves evaluating a patient’s planned drug therapy 
before a medication ...
 Typical criteria reviewed in prospective 
studies include the following:- 
 Indications 
 Drug selection 
 Doses pres...
B) Concurrent DUE:- 
◦ Performed during the course of treatment and involves 
ongoing monitoring of drug therapy to ensure...
C) Retrospective DUE :- 
◦ Simplest to perform since drug therapy is 
reviewed after the patient has received 
medication....
 In retrospective studies, the criteria 
reviewed include:- 
 Evaluation of indications and contra-indications 
 Monito...
Statistical application in Drug 
utilization research:- 
 Statistical Package for social science (SPSS) can be 
used. 
 ...
Future Perspectives: 
 The study of drug utilization in an evolving field. 
 The use of large computerized databases tha...
Conclusion:- 
 Successful research in drug utilization requires 
multidisciplinary collaboration between clinicians, 
cli...
June 7th, 2014 87
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drug utilisation studies

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DUS_Dr. Mansij Biswas

  1. 1. Drug Utilization Studies Dr. Mansij Biswas, SYR Department of Pharmacology & Therapeutics Seth G S Medical College & KEM Hospital
  2. 2. Introduction & Definition:  Pharmaco-epidemiology is the study of use and effects or side-effects of drugs in large number of people with the purpose of supporting the rational and cost effective use of drugs in population, thereby improving health outcomes.  WHO defines drug utilization research as, “the marketing, distribution, prescription and the use of drugs in a society with special emphasis on the resulting medical, social and economic consequences.”(WHO, 1977) June 7th, 2014 INTRODUCTION TO DRUG UTILIZATION RESEARCH, WHO International Working Group For Drug Statistics Methodology, WHO Collaborating Centre For Drug Statistics Methodology, WHO, 2003. 2
  3. 3. Looking back…  Initiated in Northern Europe and The UK in the mid 1960s  Arthur Engel in Sweden and Pieter Siderius in Holland described importance of comparing drug use between different countries and regions  Differences in sales of antibiotics in six European countries between 1966 and 1967 inspired WHO to organize first meeting on drug consumption in Oslo, 1969 June 7th, 2014 3
  4. 4.  Constitution of WHO European Drug Utilization Research Group (DURG)  Development of a new unit of measurement, initially called the agreed daily dose and later the Defined Daily Dose (DDD), by researchers from Ireland, Norway & Sweden  The first study used anti-diabetic drugs as an example  Among the first countries to adopt the DDD methodology was the former Czechoslovakia  First comprehensive national list of DDD was published in Norway in 1975 June 7th, 2014 4
  5. 5. Why drug utilization research?  The principal aim is to facilitate the rational use of drugs in populations.  Rational use of medicines (RUM) is defined as “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) June 7th, 2014 Promoting Rational Use of Medicines: Core Components - WHO Policy Perspectives on Medicines, No. 005, September 2002 5
  6. 6. Objectives:  Description of drug use pattern  Early signals of irrational use of drugs  Interventions to improve drug use – follow up & assessing the impact  Quality control of drug use June 7th, 2014 6
  7. 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.  Getting extent of use at certain moment or area.  Estimating to what extent drugs are properly used, overused or underused. June 7th, 2014 7
  8. 8.  Determining pattern or profile of drug use and the extent to which alternative drugs are being used to treat particular conditions.  Comparing the observed patterns of drug use for the treatment of certain disease with current guidelines.  Giving feedback of the drug utilization data to prescribers.  Assessing the potential magnitude of the problem June 7th, 2014 8
  9. 9.  Early signals of irrational use of drugs:  Comparing drug utilization patterns and cost between different regions or time period  Comparing observed patterns of drug use with current recommendation or guidelines for the treatment of certain disease June 7th, 2014 9
  10. 10.  Interventions to improve drug use-follow up:  Monitoring and evaluating the effects of measures taken to improve undesirable patterns of drug use  Following the impact of regulatory changes or changes in the insurance or reimbursement schemes  To which extent promotional activities of the pharmaceutical industry and educational activities of the society impact on the patterns of drug use June 7th, 2014 10
  11. 11.  Quality control of drug use: Drug use should be controlled according to a quality control cycle that offers a systematic framework for continuous quality improvement Step 1 : PLAN – Analyze the current situation to establish plan for improvement Step 2 : DO – Implement the plan on small scale Step 4 : ACT – Revise plan or implement plan Step 3 : CHECK – Check to see if expected results are obtained June 7th, 2014 11 on large scale
  12. 12. Types of drug use information  Drug based information  Problem or encounter based information  Patient based information  Prescriber based information  Cost based information June 7th, 2014 12
  13. 13. A) Drug based informations ◦ Data on drug use on various levels, and information on indications, doses and dosage regimen is usually necessary ◦ Level of drug use aggregation : The level at which data on drug use are aggregated will depend on question being asked.  E.g. Hypertension June 7th, 2014 13
  14. 14.  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.- ◦ antibiotic utilization ◦ Use of beta-blockers June 7th, 2014 14
  15. 15. B) Problem based informations ◦ Useful to address the question – how a particular problem is managed.  Questions that might be addressed: ◦ 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 ? June 7th, 2014 15
  16. 16. C) Patient based informations Information on demographic factors and other details about the patient are useful Age distribution – to assess the likelihood of severe adverse effects with some drugs Comorbidities of patient Knowledge, beliefs and perceptions of patients and their attitudes to drugs are important June 7th, 2014 16
  17. 17. D) Prescriber based informations This information is useful to understand how and why drugs are prescribed. ◦ Some questions that might be addressed:  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? June 7th, 2014 17
  18. 18.  Are there differences in prescribing behavior 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 ? June 7th, 2014 18
  19. 19. E) Cost based informations It will always be important in managing policy related to drug supply, pricing and use. E.g. Use of antipsychotic drugs in Australia June 7th, 2014 19
  20. 20. The DUS cycle: Planning Data collection Evaluation Feedback of results Feedback of results Interventions June 7th, 2014 20 Reevaluation
  21. 21. Steps involved in conducting a drug utilization study:- June 7th, 2014 21
  22. 22. Step 1:- Identify drugs or therapeutic areas of practice for inclusion in the program Drug-use Chain a) The systems and structures surrounding drug use  e.g. how drugs are ordered, delivered and administered in a hospital or health care facility b) The processes of drug use  e.g. what drugs are used and how they are used and does their use comply with the relevant criteria, guidelines or restrictions June 7th, 2014 22
  23. 23. c) The outcome of drug use  e.g. efficacy, adverse drug reactions and the use of resources such as drugs, laboratory tests, hospital beds or procedures.  Drug utilization studies can be targeted towards any of the above links in the drug use chain. June 7th, 2014 23
  24. 24.  Generally drugs with a high volume of use, high cost or high frequency of adverse drug reactions are subjected to DU studies  Common targets:-  Commonly prescribed drugs e.g. Antibiotics, PPIs, etc.  Drugs with significant drug interactions e.g. Warfarin, Phenytoin  Expensive drugs e.g. LMWH, Cephalosporins  Newer drugs  Drugs with a narrow therapeutic index e.g. Digoxin, Theophylline, Lithium  Drugs with serious ADRs e.g. aminoglycoside, NSAIDs etc.  Drugs in high risk patients e.g. elderly, pediatric patients  Drugs in the management of common conditions e.g. RTI or UTI, HTN, T2DM etc June 7th, 2014 24
  25. 25. Step 2:- Design of study In designing the DU study, observational research methods are more commonly used.  Accordingly, DU study can be Either :- • Quantitative • Qualitative Or :-  Cross-sectional  Longitudinal  Continuous longitudinal June 7th, 2014 25
  26. 26.  Quantitative:- Used to describe present situation and the trends in the drug prescription and drug use at various levels of the health care system.  Qualitative:- Assess the appropriateness of drug utilization and link the prescribing data to reasons for prescribing. It can be referred as Drug Utilization Review or Drug Utilization Evaluation. This process is one of the therapeutic/prescription audit. June 7th, 2014 26
  27. 27. 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 June 7th, 2014 27
  28. 28. Longitudinal studies-  Data can be on total drug use or on a statistically valid samples from pharmacies or medical practices.  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.  Provide information about concordance with treatment based on the period between prescriptions, duration of treatment, PDD etc June 7th, 2014 28
  29. 29. Continuous longitudinal study- ◦ This data can address a range of issues including reasons for change in therapy, adverse effects and health outcomes June 7th, 2014 29
  30. 30. Step 3:- Define criteria and standards  With an exhaustive literature search, identify the key literature in the chosen area of interest and the drug criteria that can be derived from this evidence based literature.  Must be valid, unambiguous, realistic, easily measured and outcome oriented. June 7th, 2014 30
  31. 31. Step 4:- Design the data collection form  It is impossible to address all aspects of use for each ◦ Patient demographics ◦ Prescriber details ◦ Indication/ Contraindications ◦ Side/adverse effects ◦ Dosing information ◦ Drug or drug class duplication ◦ Drug interactions ◦ Monitoring of drug therapy ◦ Patient education/instructions ◦ Cost of therapy individual drug BUT  It is important to limit data collection to only the most important and relevant aspects of drug use  Aspects of drug use commonly surveyed are - June 7th, 2014 37337
  32. 32. Step 5:- Data collection  Physicians, pharmacists and nurses make ideal data collectors.  Different types of drug use information are required depending upon the problem being examined. June 7th, 2014 32
  33. 33. Source of data ◦ Large databases ◦ Data from drug regulatory agency ◦ Supplier (distribution) data ◦ Practice setting data ◦ Community setting data June 7th, 2014 33
  34. 34. Large databases:- ◦ Efficient use of health care resources - Computer databases or medical record sections ◦ 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. June 7th, 2014 34
  35. 35. Data from drug regulatory agencies:-  Are repositories of data on which drugs have been registered for use, withdrawn or banned within a country.  Agencies have the legal responsibility of ensuring the availability of safe, efficacious and good quality drugs  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. June 7th, 2014 35
  36. 36. Supplier (distribution) data:-  Drug importation; local manufacture; customs service, whole salers  In countries where licenses are required from drug regulatory authorities before importation of drugs  Generally be used to describe total quantities of specific drug or drug group, origins of supplies and type (i.e. branded or generic)  Distribution at different levels of supplies can be compared June 7th, 2014 36
  37. 37. 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 June 7th, 2014 37
  38. 38.  Prescribing data: ◦ Usually extracted from outpatient and inpatient prescriptions. ◦ Information that may be obtained from prescriptions includes  Patient’s demography  Drug name, dosage form, strength, dose, frequency of administration and duration of treatment.  Where diagnoses are noted on prescriptions, is possible to link drug use to indications.  Trends in utilization for specific drugs and diseases can also be established. June 7th, 2014 38
  39. 39.  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  Drug (s) prescribed  Dose(s) prescribed  Average number of items per prescription  Percentage of items prescribed that were actually supplied (an indicator of availability)  Percentage of drugs adequately labeled  Quantity of medications dispensed  Cost of each item or prescription. June 7th, 2014 39
  40. 40.  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  The cost of individual drugs and classes of drug  The most and least expensive drugs  The per capita consumption of specific products.  The prevalence of adverse drug reactions.  The prevalence of medication errors.  The percentage of the budget spent on specific drugs or classes of drug. June 7th, 2014 40
  41. 41.  Over-the-counter and pharmacist-prescribed drugs: ◦ Pharmacists and other drug outlet managers may prescribe over the counter (OTC) preparations or pharmacist prepared drugs that do not require prescription by physician. ◦ When such information is available from stock or dispensing records, it broadens the understanding of drug utilization patterns. June 7th, 2014 41
  42. 42.  Telephone and Internet prescribing:  Mostly in developed countries.  Innovative ways need to be devised to collect information on this type of transaction. June 7th, 2014 42
  43. 43.  Community setting data:-  Drugs available in households have either been prescribed or dispensed at health facilities, purchased at pharmacy or are over the counter medications.  The drugs may be for the treatment of current illness or are left over from previous illness.  Data can be collected by performing household surveys, counting left over pills etc. June 7th, 2014 43
  44. 44. Step 6:- Evaluate results Data evaluation is the most critical step in a DUS  Summarize data into the major categories of results  Check where exactly the data shows deviation from the guidelines and usage criteria  Check whether true deviation exists  Evaluate reasons for this deviation  May be necessary to redefine the criteria June 7th, 2014 44
  45. 45.  Reasons for deviation may include: ◦ Drug being used for new indication ◦ Outdated procedures ◦ Inadequate resources ◦ Gaps in knowledge or misinformation / misunderstanding  Evaluation is done with the help of:- Drug Utilization Metrics Drug Use Indicators Drug classification systems June 7th, 2014 45
  46. 46. Drug utilization metrics include:-  Defined daily dose  Prescribed daily dose  Other units for presentation of volume  Cost June 7th, 2014 46
  47. 47. Defined daily dose (DDD):- 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 and does not necessarily correspond to the recommended or prescribed daily dose (PDD). 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. June 7th, 2014 47
  48. 48.  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. June 7th, 2014 48
  49. 49.  DDDs per 1000 inhabitants per day:- ◦ Provide a rough estimate of the proportion of the study population treated daily with a particular drug or group of drugs. ◦ E.g.- 10 DDDs per 1000 inhabitants per day indicates that 1% of the population on average might receive a certain drug or group of drugs daily. ◦ Most useful for chronically used drugs June 7th, 2014 49
  50. 50.  DDDs per inhabitant per year:- ◦ Estimate of the average number of days for which each inhabitant is treated annually E.g. - ◦ 5 DDDs per inhabitant per year indicates that the utilization is equivalent to the treatment of every inhabitant with a five-day course during a certain year. June 7th, 2014 50
  51. 51.  DDDs are not established for:- ◦ Topical products ◦ Sera, vaccines ◦ Antineoplastic agents ◦ Allergen extracts ◦ General and Local anesthetics ◦ Contrast media June 7th, 2014 51
  52. 52. Prescribed daily dose (PDD):-  The prescribed daily dose (PDD) is defined as the average dose prescribed according to a representative sample of prescriptions.  Can be determined from studies of prescriptions or medical or pharmacy records  Gives the average daily amount of a drug that is actually prescribed June 7th, 2014 52
  53. 53.  The PDD can vary according to both the illness treated and the national therapeutic traditions.  The PDDs differ: ◦ Between countries and ethnic groups ◦ Between areas or health care facilities within the same country ◦ For different indications of the same drug June 7th, 2014 53
  54. 54.  PDD does not necessarily reflect actual drug utilization.  Specially designed studies including patient interviews are required to measure actual drug intake at the patient level (i.e. the consumed daily dose). June 7th, 2014 54
  55. 55. Other units for presentation of volume: These units can be applied only when the use of a single drug or of well defined combination product is evaluated.  Grams of active ingredient:- ◦ Drugs with low potency will account for a larger fraction of the total than drugs with high potency ◦ Combined products may also contain different amounts of active ingredients from plain products June 7th, 2014 55
  56. 56.  Number of tablets:- ◦ Counting numbers of tablets does not reflect the variations in strengths of tablets, with the result that low-strength preparations contribute relatively more than high-strength preparations to the total numbers  Numbers of prescriptions:- ◦ Do not accurately reflect total use, unless total quantities of drugs per prescription are also considered. ◦ Valuable in measuring the frequency of prescriptions June 7th, 2014 56
  57. 57. Cost:- ◦ Cost figures are suitable for an overall analysis of expenditure on drugs. ◦ International comparisons based on cost parameters can be misleading and have limited value in the evaluation of drug use. ◦ Difficulties in evaluation may be due to  Price differences between alternative preparations  Fluctuations in currency  Changes in price June 7th, 2014 57
  58. 58. Drug Use Indicators:-  Prescribing indicators ◦ Average number of drugs per encounter ◦ Percentage of drugs prescribed by generic name ◦ Percentage of encounters with an antibiotic prescribed ◦ Percentage of encounters with an injection prescribed ◦ Percentage of drugs prescribed from essential drugs list or formulary June 7th, 2014 58
  59. 59.  Patient care indicators ◦ Average consultation time ◦ Average dispensing time ◦ Percentage of drugs actually dispensed ◦ Percentage of drugs adequately labelled ◦ Patients' knowledge of correct dosage  Facility indicators ◦ Availability of copy of essential drugs list or formulary ◦ Availability of key drugs ◦ Availability of clinical guidelines June 7th, 2014 59
  60. 60.  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 ** WHO-INRUD (International Network for the Rational Use of Drugs) –WHO-1993 June 7th, 2014 60
  61. 61. Prescribing indicators:- 1. Average number of drugs per encounter total number of different drug products prescribed Average = -------------------------------------------------------------- number of encounters surveyed 2. Percentage (%) of drugs prescribed by generic name number of drugs prescribed by generic name × 100 % = --------------------------------------------------------------- total number of drugs prescribed June 7th, 2014 61
  62. 62. 3. Percentage of encounters with an antibiotic prescribed 4. Percentage of encounters with an injection prescribed Number of patient encounters during which an antibiotic or an injectable are prescribed x 100 % = ----------------------------------------------- Total number of encounters surveyed June 7th, 2014 62
  63. 63. 5. Percentage of drugs prescribed from essential drugs list or formulary The number of products prescribed which are listed on the essential drugs list or local formulary x 100 % = -------------------------------------------------- The total number of drugs prescribed June 7th, 2014 63
  64. 64. Patient care indicators:- 1. Average consultation time Total time for a series of consultation Average=------------------------------------------------------ Number of consultations 2. Average dispensing time Total time for dispensing drugs to a series of patients Average=------------------------------------------------------ Number of encounters June 7th, 2014 64
  65. 65. 3. Percentage of drugs actually dispensed number of drugs actually dispensed at the health facility × 100 %= ------------------------------------------------------------- total number of drugs prescribed 4. Percentage of drugs adequately labeled number of drug packages containing at least patient name, drug name and when × 100 the drug should be taken %= ----------------------------------------------------------------- total number of drug packages dispensed June 7th, 2014 65
  66. 66. 5. Patients' knowledge of correct dosage  To reliably evaluate the correctness of patients' responses about when they are to take the drugs, clear guidelines should be developed about common dosage regimens number of patients who can adequately report the dosage schedule for all the drugs x 100 %= -------------------------------------------------------------- total number of patients interviewed June 7th, 2014 66
  67. 67. Facility indicators:- 1. Availability of copy of essential drugs list or formulary 2. Availability of clinical guidelines ◦ A national essential drugs list or a local formulary and a clinical guideline must exist ◦ Scored as ‘Yes’ or ‘No’, per facility 3. Availability of key drugs number of specified products actually in stock × 100 % = ---------------------------------------------------------------- total number of drugs on the checklist June 7th, 2014 67
  68. 68. Model list of Key Drugs for testing drug availability:- Diarrhoea oral rehydration salts cotrimoxazole tablets Acute respiratory tract infections cotrimoxazole tablets procaine penicillin injection paediatric paracetamol tablets Malaria chloroquine tablets Anaemia ferrous salt + folic acid tablets Worm infestations mebendazole tablets Conjunctivitis tetracycline eye ointment Skin disinfection iodine, gentian violet or local alternative Fungal skin infection benzoic acid + salicylic acid ointment Pain/fever acetylsalicylic acid or paracetamol tablets Prophylactic drugs retinol (vitamin A) ferrous salt + folic acid tablets June 7th, 2014 77 68
  69. 69. Drug classification system:-  The main purpose of having an international standard is to be able to compare data between countries.  Different classification systems : - ◦ Anatomical Therapeutic Chemical (ATC) classification develop by Norwegian researchers.  serve as a tool for presenting drug utilization statistics  recommended by WHO for international comparisons June 7th, 2014 69
  70. 70. ◦ Anatomical Therapeutic (AT) classification developed by the European Pharmaceutical Market Research Association (EPhMRA)  The EPhMRA classification system is used worldwide by IMS (International Marketing Services) for providing market research statistics to the pharmaceutical industry. June 7th, 2014 70
  71. 71. Step 7:- Provide feedback of results  Prepare a scientific interpretation of the results rather than a value judgment.  Success of any DUS depends on feedback of results to prescribers, other hospital staffs involved in the study and to administrative heads.  The results can also be circulated to hospital staff via newsletters or the hospital’s academic meetings. June 7th, 2014 71
  72. 72. Step 8:- Develop and implement interventions  If a drug use problem is identified the next step is to consider how the problem can be addressed.  Interventions:- ◦ Educational - educational meetings, development of protocols, letters to individual physicians. ◦ Operational - modification of drug order forms, development of stringent drug use policy, manual or computerized reminders, prescribing restrictions, formulary additions/deletions etc. June 7th, 2014 72
  73. 73. Step 9:- Re-evaluate to determine if drug use has improved  Drug use and prescribing patterns need to be monitored to determine the success of intervention  Re-evaluation is usually done 3-12 months after the introduction of the intervention  Collection of data as in original DUS  Should be a continuous process at regular interval June 7th, 2014 73
  74. 74. Step 10:- Re-assess and revise the DUS program Results of the previous DU studies help to improve quality, efficacy and effectiveness of future DU studies. June 7th, 2014 74
  75. 75. Step 11:- Feedback results  Circulate results of the DUS  Obtain opinions about success of interventions and improvement of drug use.  Analyze and act accordingly June 7th, 2014 75
  76. 76. DU 90%  Reflects the number of drugs that account for 90% of drug prescriptions and adherence to local or national prescription guidelines  Can be applied at different levels ◦ Individual prescriber ◦ Group of prescribers ◦ Wards ◦ Hospitals ◦ County  Gives a rough estimate of the quality of prescribing. June 7th, 2014 76
  77. 77. Drug utilization evaluation  Drug utilization evaluation (DUE) is defined as an authorized, structured, ongoing review of physician prescribing, pharmacist dispensing and patient using medication.  DUE is ongoing, systematic process designed to maintain the appropriate and effective use of drugs  Synonymous- Drug Utilization Review (DUR)  Medication use evaluation (MUE) is similar to DUE but emphasizes on improving patient’s clinical outcome and individual quality of life. June 7th, 2014 77
  78. 78. 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. June 7th, 2014 78
  79. 79. Classification of DUE: A) 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. June 7th, 2014 79
  80. 80.  Typical criteria reviewed in prospective studies include the following:-  Indications  Drug selection  Doses prescribed  Dosage form and routes of administration  Duration of therapy  Costs  Therapeutic duplication  Quantity dispensed  Contraindications  Therapeutic outcomes  Adverse drug reactions and drug interactions  Generic substitution June 7th, 2014 80
  81. 81. B) Concurrent DUE:- ◦ Performed during the course of treatment and involves ongoing monitoring of drug therapy to ensure positive patient outcomes.  Typical criteria reviewed:- ◦ Drug interactions ◦ High or low dosages ◦ Duplicate therapy ◦ Drug-disease interaction ◦ Over and under utilization ◦ Drug-age precautions ◦ Drug-gender precautions ◦ Drug-pregnancy precautions June 7th, 2014 81
  82. 82. C) 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. June 7th, 2014 82
  83. 83.  In retrospective studies, the criteria reviewed include:-  Evaluation of indications and contra-indications  Monitoring high cost medicines  Comparison of prescribing between physicians  Cost to patient  Over and under utilization  Incorrect drug dosage  Inappropriate duration  Adverse drug reaction  Drug interactions June 7th, 2014 83
  84. 84. 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. June 7th, 2014 84
  85. 85. 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 June 7th, 2014 85
  86. 86. 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. June 7th, 2014 86
  87. 87. June 7th, 2014 87

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