Chapter 7 - Evaluation of Literature - Lebanese International University

Lebanese International University School of Pharmacy Pharmacy Practice Department Chapter 9: Evaluation of Literature PHAR200 – Introduction to Drug Information Spring Semester, 2023 - 2024  Chapters: 1. Medical Terminologies 2. Drug Evaluation Monograph 3. Pha...

Lebanese International University School of Pharmacy Pharmacy Practice Department Chapter 9: Evaluation of Literature PHAR200 – Introduction to Drug Information Spring Semester, 2023 - 2024  Chapters: 1. Medical Terminologies 2. Drug Evaluation Monograph 3. Pharmacist Patient Care Process (PPCP) 4. Drug Information Resources 5. Drug Consult 6. Referencing 7. Drug Information Center (DIC) 8. Introduction to Biostatistics 9. Evaluation of Literature 10. Evaluation of Journal Club 11. Evidence-based Clinical Practice Guidelines 2  School of Pharmacy Lebanese International University PHAR200 – Introduction to Drug Information Chapter 9: Evaluation of Literature 3  What is a Study Design? Study designs are the set of methods and procedures used to collect and analyze data in a study to answer a specific research question If the study is designed properly then the data generated is valid and proper analysis provides the valid statistical results If the experiment is not well designed, the validity of the statistical results is questionable and may be invalid 4  Why is it Important to Understand the Design? The researchers (persons conducting the study) may use the inappropiate study design Use the right method incorrectly Misinterpret the results Draw incorrect conclusions from their study Report their results selectively or incorrectly Reference other studies selectively or incorrectly 5  CONSORT Consolidated standards of reporting trials o Contains checklists for the authors of trials to use when submitting a manuscript to medical journals o Adopted by different medical journals: Lancet, Annals of Internal Medicine, JAMA o BUT cannot prevent authors from bias Successful pharmacy practitioners must have good skills to critically evaluate the primary literature o CONSORT recommendations are not enough! 6  Study Design Selection Researchers select the design of their study based on: o Number of patients required to obtain meaningful results o Study’s complexity o Amount of time required to conduct the study o Cost of the study 7  14 Types of Studies Study type Descriptive Explanatory Case Case-serie Non-experimenta Experimental report s l Observational Case Case Cross-secti Controlled Uncontrolled control cohort onal trials trials  Study Type: Descriptive Document experiences or new events that the author feels are important to bring to the attention of the medical community o The investigator records data from observations and draws conclusions Include 2 major types 1. Case series 2. Case report 9  Study Type: Descriptive – Case Series Document observations from a group or series of patients and record the outcomes Used to estimate the incidence of an adverse event of a newly marketed drug o Ex: Suicidal ideas following haloperidol use Allow generation of hypotheses that are subsequently investigated in explanatory studies Describe unusual or new events BUT Do not provide definitive explanations, determine causes, or supply evidence that one drug superior is to another 10  Study Type: Descriptive – Case Report A detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient o Usually describe an unusual or novel occurrence o Based on observations of individual patients → 1 case report per individual 11 Study Type: Explanatory – Observational Study Investigators o Examine the natural course of health events o Gather data about subjects included o Classify and sort data Include 3 major types: 1. Case control 2. Case cohort 3. Case cross-sectional 12 Explanatory – Observational Study – Case Control Works from the effect or outcome back to the cause or exposure Retrospective study: Effect(Outcome) → Cause(Exposure) o Begins with the absence/presence of an outcome and then look backward in time to detect possible causes or risk factors o Association determined by odds ratio (>1) o Ex: Alcohol ← Liver damage 13 Explanatory – Observational Study – Case Control Advantages Disadvantages Quick Detailed mechanism about the study is not available Low cost (Recall bias) Reliance on patient recall/medical records for the evaluation Small sample size Difficulty to select an appropriate control group Efficient for the study of chronic diseases that (Surveillance bias) Asymptomatic disease or are already developed - No need to wait for mild disease might escape reporting time to elapse between exposure and disease manifestations (Reporting bias) When publicity of the disease leads to a false increase in disease reporting 14 Explanatory – Observational Study – Case Cohort Proceed from the cause or exposure to the effect or outcome Prospective study: Cause(Exposure) → Effect(Outcome) o Use existing reports o Measure of certain outcomes may require years of follow-up o Association determined by relative risk (>1) o Ex: Smoking → Lung cancer 15 Explanatory – Observational Study – Case Cohort Advantages Disadvantages Easy to establish exposure Lost to follow-up [Uneven distribution] More robust study design than case-control Changes in subject characteristics over time studies Greater assurance that the characteristics led to Difficulty to select an appropriate control group the disease Efficient for the study of study of rare exposures Surveillance bias: changes in diagnostic methodologies Effective in detecting the main risk factors Long time to complete the study No recall bias High cost + Large sample size 16 Study Type: Explanatory – Observational Study Case Control Case Cohort Retrospective Prospective Odds ratio Relative risk Low cost High cost Small sample size Large sample size Effect → Cause Cause → Effect 17  Explanatory – Observational Study – Case Cross-sectional Gather information at one point in time o Quick and easy but do not permit distinction between cause and effect o Primarily used to determine prevalence at a certain time o Subjects are neither deliberately exposed, treated, or not treated → No ethical difficulties ▪ Only one group is used, data are collected only once and multiple outcomes can be studied 18  Explanatory – Observational Study – Case Cross-sectional Advantages Disadvantages Quick + cheap + Less time consuming Do not themselves differentiate between cause and effect or the sequence of events No follow up → Less resources required to run Do not provide an explanation for their findings the study Best way to determine prevalence Not used for rare diseases Can study multiple outcomes 19 Study Type: Explanatory – Experimental Study Experimental studies are designed to control as many variables as possible to measure a specific outcome o Experimental studies in medicine that involve humans are called clinical trials because their purpose is to draw conclusions about a particular procedure or treatment Include 2 major types: 1. Controlled – Randomized/Non-randomized 2. Uncontrolled 20  Explanatory – Experimental Study – Controlled The design of these trials includes at least one study group that is compared with a control group Experimental group: ▪ Those who receive the investigational drug Control group: ▪ Those who don’t receive such treatment. They can receive placebo or another effective treatment approved for the disease on which the study is being carried out This is achieved simply by randomly assigning subjects to experimental or control groups 21  Explanatory – Experimental Study – Controlled Experimental controlled studies include 2 types: o Randomized controlled trial (RCT): Method of randomly allocating treatments to patients into therapeutic research RCTs are the GOLD STANDARD for assessing the effectiveness of therapeutic agents It provides the best scientific evidence to any study These are generally quite expensive 22  Explanatory – Experimental Study – Controlled Experimental controlled studies include 2 types: Non-randomized controlled trial o Non-randomized controlled trial: Subjects in a population are non-randomly allocated to different groups It is not considered as a ‘Gold Standard’ These are generally less expensive 23  Explanatory – Experimental Study – Controlled The controls that are usually used are: o Placebo control: Using an inert substance or an intervention designed to simulate investigational medical therapy, but have no effect on the pathology under investigation. The placebo should have the same appearance and dose frequency as the active drug. o “No treatment” control: Patients in the control group are not given any intervention or treatment o Active treatment control: This design involves comparing a new drug with a standard drug or comparing the combination of new and standard therapies versus standard therapy alone. o Historical control: they are patients who were treated at an earlier time or in a different setting and compared in the current trial 24 Explanatory – Experimental Study – Uncontrolled ❑ Uncontrolled trials are those that do not include a control group ❑ Researchers have no control over whether their subjects receive the treatment being investigated 25  Blinding of The Trial Blinding is a procedure in which one or more parties in a trial are kept unaware of which treatment arms participants have been assigned to Blinding prevents conscious or unconscious bias in the design of a clinical trial and ensures the objectivity of participants, study staff Type Description Unblinded or open label All are aware of the treatment(s) Single blind or The participants are blinded but no one else is single-masked Double blind or The participants and clinicians are blinded double-masked 26  Meta-Analysis Meta-analysis is a type of study that does not fit specifically in either category of observation studies or experiments ✔ Uses published information from other studies and combines the results so as to permit an overall conclusion and increases statistical power ✔ Is especially appropriate when the studies that have been reported have small numbers of subjects or come to different conclusions 27 Strength of Evidence Derived from Studies: Ranking by Study Design Controlled, randomized, double-blind trials are the “Gold Standard” in clinical research Weak 28