INTRODUCTION TO PHARMACOEPIDEMIOLOGY.pptx

Pharmacoepidemiology is the one of branch deals with distribution of diseases and outcome measurement, etc.

1. Ameena Kadar K A Second Sem , M pharm Dept. of Pharmacy Practice Sanjo College of Pharmaceutical Studies INTRODUCTION TO PHARMACOEPIDEMIOLOGY

2. 2 INTRODUCTION Epidemiology is the study of occurrence, distribution and determinants of health and diseases or disorders in man and its application in controlling health problems. Epidemiology has by tradition two major areas . First is the study of infectious diseases that spread to large populations, i.e., epidemics. The second is the study of chronic diseases . Epidemiological studies help to solve such health problems and provide a basis for improving living conditions of the people. During its progress and development, epidemiology has made available precise and strict methodologies for the study of diseases.

3. 3 Pharmacology is the study of the effects of drugs. Clinical Pharmacology is the study of the effects of drugs in humans, It is traditionally divided into two basic areas namely: Pharmacokinetics Pharmacodynamics. Pharmacokinetics is the study of the relationship between dose administered of a drug and the serum or blood level achieved, it deals with absorption, distribution, metabolism and excretion. Pharmacodynamics is the study of the relationship between drug level and drug effect. Clinical pharmacology helps one to predict the effect in a patient after administering a certain drug regimen.

4. 4 Pharmacoepidemiology encompasses elements of both these fields, exploring the effects achieved by administering a drug regimen. The core of pharmacoepidemiology lies at the intersection of epidemiology and clinical pharmacology. The contemporary activities of the pharmacoepidemiology has three aspects in its coverage: Epidemiology Clinical Pharmacology Clinical Pharmacy.

5. 5 PHARMACOEPIDEMIOLOGY Epidemiology is the study of the distribution and determinants of diseases in populations. Epidemics is the study of chronic/ infectious diseases in large populations. Pharmacoepidemiology is the study of the use of and the effects of drugs in large number of people. It involves the examination of a single individual or large groups of people followed for many years. It involves gathering & analysis of information in order to identify possible causation & related factors , that can be applied in clinical practice to group of people & also to individuals undergoing treatment.

6. 6 It applies the principles of clinical pharmacology, clinical epidemiology and biostatistics. The Pharmacoepidemiological studies concentrate on the period after the drug enters the market known as Post Market Surveillance (PMS) period.

7. 7 NEED OF PHARMACOEPIDEMIOLOGY Lack of alternative models to investigate some drug events E.g .: to evaluate teratogenic effects of a new medicine Clinical Trials (CTs) are inadequate to answer questions about drug safety, as they lack adequate statistical power. If at all adequate for establishing effectiveness, the sample size are inadequate to detect less common ADRs. CTs are conducted on highly selected patients without any co-morbidities & who taking no other medications. CTs does not involve elderly, pediatric or pregnant patients. CTs investigate the single indication, hence , CTs fail to provide adequate information related to safety & efficacy of a drug under non-trial conditions & in other indications. Pharmacoepidemiological models provide alternative approaches to evaluate drug effects.

8. 8 AIMS OF PHARMACOEPIDEMIOLOGY Pharmacoepidemiological studies are concerned with two main aspects: The study of adverse effects of drugs The appropriate use of medicines. Pharmacoepidemiological studies focus on, Global trends in prescribing
Appropriateness of drug use
Medication adherence
Lifestyle effect on drug therapy
Special population on drug therapy
Drug interaction
Predictable ADRs

9. 9 Aims: Signal Generation Risk Quantification Hypothesis Testing Signal Generation The term signal is used in ADR reporting and Pharmacovigilance as an early warning in the case of ADRs. Signal is a reported information on possible causal relationship between adverse event and a drug or medicine. Helps to identify new application of existing drug Eg: Aspirin – first used for pain & inflammation later used in cardiac diseases due to blood thinning property . Minoxidil is used as Antihypertensive and Hirustism .

10. 10 It is the process of evaluating risks that have been identified and developing the data for other purposes like making decisions on other occasions. Various measures of the risk are used in Pharmacoepidemiology to quantify the probability of experiencing an adverse outcome capture the relative increases in risk between treated and untreated populations. V arious measures of risk includes: Cumulative incident Incident rate Relative risk Odds ratio. Risk Quantification

11. 11 It involves use of comparison group to determine whether there are differences in variable of interest (risk factor, trait, characteristic or drug exposed) Statistical methods are used to assess whether the observed difference occurred by chance. It gives a conclusion about relationship between exposure to a drug and clinical event. Hypothesis Testing

12. 12 APPLICATIONS Estimation of the risks of drug use Use in patient counseling Formulation of public health policy decisions Facilitation of pharmacoeconomic evaluations In pharmacovigilance To carry out drug usage analysis Formulation of therapeutic guidelines Health outcomes research.

13. 13 Estimation of the risks of drug use: The risk involved in drug use can be quantified. The benefits & risks of use of a drug may be weighed. Risk estimation also helps to identify risk situation Ex : Case reports of triazolam induced psychiatric disturbances appeared soon after its introduction to market. The drug was withdrawn in some countries. The reaction was likely due to dose related, hence the problem was abated by recommending a lower dose.

14. 14 2. Use in patient counseling: Collection & analysis of observational data from other studies may help to address certain issues through counseling the patients. Ex : A pregnant patient may wish to terminate pregnancy if there is a substantial risk for producing a seriously malformed child, but would also wish to proceed with the pregnancy if the risk is low.

15. 15 3. Formulation of public health policy decisions: Qualitative as well as quantitative information from Pharmacoepidemiological studies helps to address many issues. Ex : If an inappropriate prescribing is observed among prescribers, regulatory agencies may require educational intervention or may impose restrictions on specific drugs or on practitioners. P harmacoepidemiological studies also helps the policy makers to assess whether a drug should be withdrawn from the market or allowed to remain.

16. 16 4. Facilitation of pharmacoeconomic evaluations: Data from P harmacoepidemiological studies can be used to measure the effects of drugs on overall health care costs & resource consumption. Ex : Hospitalization due to serious adverse effects of a drug leads to more expenses as well as resource consumption, which could be avoidable. 5. In pharmacovigilance Pharmacoepidemiological studies are useful to monitor ADR and find out incidence and risk/benefit of drug. Prevention and reduction of occurrence of ADR.

17. 17 7. Formulation of therapeutic guidelines: PE studies helps to examine the effectiveness of drugs in elderly & pediatric patients and also in patient with co morbidities. From these data therapeutic guideline can be prepared. 8. Health outcomes research : Investigating the impact of medications on patient outcomes, such as mortality, morbidity, quality of life, and healthcare utilization . 6. To carry out drug usage analysis Used to identify over usage, under usage and non-usage of medicine in population Medicine usage pattern are studied on a set of population.

18. 18 Other applications of PE studies include: Pharmacogenomics studies: helps to identify focus area of pharmacogenomics study Age based medicine use and its analysis Evaluation of hospital committee Generation of database for other studies.

19. 19 Outcome measurement : It is defined as the systematic quantitative analysis of outcome indicator at a point of time. These measures are used to find out whether the goal of the patient, are identified and achieved.

20. 20 OUTCOME MEASURES Measuring outcomes is an important component for management of individual patient by collectively comparing care and determining effectiveness. The use of standardized tests and measures early in an episode of care establishes the baseline status of the patient/client, providing a means to quantify change in the patient's/client's functioning. Outcome measures, along with other standardized tests and measures used throughout the episode of care, as part of periodic reexamination, provide information about whether predicted outcomes are being realized.

21. 21 Clinical outcome assessments (COAs) measure a patient’s symptoms, overall mental state, or the effects of a disease or condition on how the patient functions. COAs can be used to determine whether or not a drug has been demonstrated to provide treatment benefit. Treatment benefit can also be defined in terms of a safety benefit compared to other treatments. Types of COA measures : Patient-reported outcome (PRO) measures Clinician-reported outcome ( ClinRO ) measures Observer-reported outcome ( ObsRO ) measures Performance outcome ( PerfO ) measures.

22. 22 Outcome measures include studies on: Functional status (level of functioning, Supervision required, ability to work) Symptom status (days free of pain / an event) Patient satisfaction with various aspects of care (delivery of care, effects on daily activities or life satisfaction) and Quality of Life ( QOL)studies The therapeutic outcomes may be classified as cure, improvement, no change or deterioration. On the other hand, they can be classified as success or failure.

23. 23 GOALS OF MEASURING CLINICAL OUTCOMES Improve the patient experience of care. Improve the health of populations. Reduce the per capita cost of healthcare. COMMON OUTCOME MEASUREMENT Morbidity: M easured as the number of cases of disease or events that occur per unit of population ( per 100 ), unit of time ( per year) or both. Mortality : Deaths occurring due to transmission of a disease or due to or prevented by the use of drugs Readmission Safety of care Patient experience Effectiveness of care Timeliness of care Efficient use of medical imaging.

24. 24 METHODS OF OUTCOME MEASUREMENT STATISTICAL METHODS DRUG USE METHODS 1. STATISTICAL METHODS PREVALENCE: It is the proportion of people affected with a disease or exposure to a particular drug in a population at a specific period of time. It is usually determined by surveying the population of interest. It is a census type of measure, indicating how frequently a disease is at a period of time. It varies between 0-1, expressed as %.

25. 25 Uses: Estimate the magnitude of health (or) disease problem in the community To identify the potential high risk population community Useful for administrative & planning purpose. Prevalence = No. of population with disease at a given time Total no: of population at a given time b ) INCIDENCE : It is a measure of the risk of developing some new condition within a specified period of time. It is better expressed as a proportion or as a rate.

26. 26 Cumulative incidence (CI ) : It is a no. of new cases within a specific period of time, divided by the size of population initially at risk. It is used for the measure of the risk of disease or probably the probability of developing the disease during specific period. Normally, it is measured with an inception cohort, that is large group of population is observed over a period of time, and the no: of cases or outcomes measured . CI = No. of new cases of disease (or) injury during specific period Size of population at start of period

27. 27 Incidence rate : It is the no. of new cases per population at risk in a given period of time. It describes the probability of a new case occurring during a given time interval. IR = No : of new cases of diseases (or) injury during specific period Total time each person was observed Relationship Between Prevalence And Incidence P = I × D where, P: Prevalence I : Incidence D: Duration Longer the duration of disease, greater the prevalence .

28. 28 REFERENCES A Textbook pf Pharmacy Practice, K G Revikumar , Revised second edition. Page No: 367- 391. www.PharmaDost.info THANK YOU!!