SlideShare a Scribd company logo
1 of 23
Dr. Animesh Gupta
MD,FDM,FAGE
Associate Professor, Dept. of Community Medicine, NMCH, Sasaram (Bihar)
4/25/2020Case Control Study Dr Animesh Gupta
1
At the end of the class, the students should know
▪ Different types of epidemiological methods
▪ Salient features of case control study
▪ Steps for conducting case control study
▪ Matching
▪ Odds ratio
▪ Bias in case control study
▪ Advantages & disadvantages in case control study
4/25/2020Case Control Study Dr Animesh Gupta 2
OBSERVATIONAL STUDIES
DESCRIPTIVE STUDY ANALYTICAL STUDIES
✓ TIME
✓ PLACE
✓ PERSON
➢ ECOLOGICAL STUDY
➢ CROSS SECTIONAL STUDY
➢ CASE-CONTROL STUDY
➢ COHORT STUDY
EXPEREMENTAL STUDIES
➢ RANDOMIZED CONTROLLED TRIAL (RCT)
➢FIELD TRIAL
➢COMMUNITY TRIAL 4/25/2020Case Control Study Dr Animesh Gupta 3
▪Makes careful measurement of patterns of exposure and
disease in population
▪Comparison group
▪The object is not to formulate but to test the hypothesis.
▪To evaluate an association between exposure and disease.
4/25/2020Case Control Study Dr Animesh Gupta 4
▪The observational epidemiologic study of persons with the
disease (or other outcome variable) of interest and a
suitable control (comparison/ reference) group of persons
without the disease. (- John M Last)
▪It is an observational study in which subjects are sampled
based upon presence or absence of disease and then their
prior exposure status is determined.
4/25/2020Case Control Study Dr Animesh Gupta 5
▪ Also knowns as “retrospective study”
▪ From effect to cause
▪ The case control method has three distinct features:
▪ Both exposure and out come have occurred before the start of
the study.
▪ The study proceeds backwards from effect to cause.
▪ It uses a control or comparison group to support or refute
an inference.
4/25/2020Case Control Study Dr Animesh Gupta 6
4/25/2020Case Control Study Dr Animesh Gupta 7
1. Selection of cases and controls
2. Matching
3. Measurement of exposure
4. Analysis & interpretation
4/25/2020Case Control Study Dr Animesh Gupta 8
▪Study begins with cases, i.e. the patients in whom the disease
has already occurred.
▪Cases were enquired for all the details of their exposure to the
suspected cause.
▪Definition of case:
▪ Diagnostic criteria : Clear cut diagnostic criteria of the disease
and its stage.
▪ Eligibility criteria : It is always advisable to take the incident
cases,since the prevalent cases might have changed their
exposure status due to medical advice etc.
4/25/2020Case Control Study Dr Animesh Gupta 9
▪Sources of Cases
▪ Hospitals
▪ Single hospital or a network of hospitals, admitted during a specified
period of time.
▪ The entire case series or a random sample of it is selected for study.
▪ General population
▪ Defined geographic area during a specified period of time
▪ Can be taken data through a survey, a disease registry or hospital
network.
▪ The cases should be fairly representative of all cases in the
community. 4/25/2020Case Control Study Dr Animesh Gupta 10
▪ Controls must be free from disease
▪ Must be similar to the cases as far as possible except for the
absence of disease.
▪ Sources:
▪ Hospital control
✓Different illness other than the study disease
▪ Relatives
✓Except genetic condition study
▪ Neighborhood
✓Same locality/ working in same area/factory
▪ General population
✓Defined geographic areas
4/25/2020Case Control Study Dr Animesh Gupta 11
▪Select controls from various diagnostic groups, so no
particular risk factors will be over represented
▪Select controls from patients with acute conditions, so
earlier exposures could not have been influenced by the
condition
▪Do not select patients who have multiple concurrent
conditions.
▪Do not select patients with diagnoses known to be related
to the risk factor of interest
4/25/2020Case Control Study Dr Animesh Gupta 12
▪ Matching is the process of selecting controls who
are similar to the cases in certain key
characteristics (eg.age,sex,race) which are
known to influence the outcome of the disease.
▪ Individual matching (matched pair)
▪ for each case, a control is selected who is similar to the
case for a given variable
▪Group matching (frequency matching)
▪ proportion of controls with a given characteristic
(variable) is identical to proportion of cases with the same
characteristic
4/25/2020Case Control Study Dr Animesh Gupta 13
▪Defined as one which is associated both with exposure and
disease and is distributed unequally in study and control
groups.
▪Alcohol & Oesophageal cancer study – smoking is a
confounding factor.
4/25/2020Case Control Study Dr Animesh Gupta 14
To find out
▪Exposure rate among cases and controls to suspected
factor.
▪Estimation of disease risk associated with exposure (Odds
ratio).
4/25/2020Case Control Study Dr Animesh Gupta 15
Cases Controls
Risk factor + a b
Risk factor -- c d
4/25/2020Case Control Study Dr Animesh Gupta 16
▪Among cases = a/a+c
▪Among controls = b/b+d
4/25/2020Case Control Study Dr Animesh Gupta 17
▪Odds = is the ratio of the probability that an event will
happen to the probability that it will not happen
▪Odds ratio / cross product ratio
= ad/bc
▪It interprets that odds of cases being exposed are so many
times higher compared to the odds of controls being
exposed.
4/25/2020Case Control Study Dr Animesh Gupta 18
▪Based on 3 assumption that
▪Disease being investigated must be relatively rare.
In fact majority of the chronic disease have a low incidence in
the general population.
▪The cases must be representative of those with the disease.
▪The controls must be representative of those without the
disease.
4/25/2020Case Control Study Dr Animesh Gupta 19
It is systematic error in the determination of the association
between the exposure and the disease.
▪Bias due to confounding factor
▪Memory or recall bias
▪Selection bias
▪Interviewer’s / Observer bias
▪Berkesonian bias ( Dr Joseph Berkeson)
▪ Different rates of admission to the hospital with different
disease.
4/25/2020Case Control Study Dr Animesh Gupta 20
Strength
▪ Good for examining rare
outcomes or outcomes with
long latency
▪ Relatively quick to conduct,
inexpensive
▪ Requires comparatively few
subjects
▪ Multiple exposures or risk
factors can be examined.
Weakness
▪ Bias
▪ Selection of an appropriate
control group may be
difficult
▪ Incidence cant be calculated
▪ Do not distinguish between
causes and associated
factors
4/25/2020Case Control Study Dr Animesh Gupta 21
▪It is usually conducted before a Cohort or Experimental
Study to identify the possible etiology of the disease.
▪ It costs relatively less and can be conducted in a shorter time
▪For a given disease, a case control study can investigate
multiple exposures (when the real exposure is not known)
▪Case control study is preferred when the disease is rare
because investigator can intentionally search for the cases.
4/25/2020Case Control Study Dr Animesh Gupta 22
Thank You
4/25/2020Case Control Study Dr Animesh Gupta
23

More Related Content

What's hot

Introduction to meta-analysis (1612_MA_workshop)
Introduction to meta-analysis (1612_MA_workshop)Introduction to meta-analysis (1612_MA_workshop)
Introduction to meta-analysis (1612_MA_workshop)Ahmed Negida
 
randomised controlled trial
randomised controlled trial randomised controlled trial
randomised controlled trial DrSridevi NH
 
Nested case control,
Nested case control,Nested case control,
Nested case control,shefali jain
 
Cohort studies..NIKHNA JAYAN
Cohort studies..NIKHNA JAYANCohort studies..NIKHNA JAYAN
Cohort studies..NIKHNA JAYANNikhna jayan
 
Chapter 2.2 screening test
Chapter 2.2 screening testChapter 2.2 screening test
Chapter 2.2 screening testNilesh Kucha
 
2-Epidemiological studies
2-Epidemiological studies2-Epidemiological studies
2-Epidemiological studiesResearchGuru
 
Validity & reliability of screening & diagnostic tests
Validity & reliability of screening & diagnostic testsValidity & reliability of screening & diagnostic tests
Validity & reliability of screening & diagnostic testsTanveerRehman4
 
Bias and confounding
Bias and confoundingBias and confounding
Bias and confoundingIkram Ullah
 
Survival analysis & Kaplan Meire
Survival analysis & Kaplan MeireSurvival analysis & Kaplan Meire
Survival analysis & Kaplan MeireDr Athar Khan
 
Kaplan Meier Survival Curve Analysis
Kaplan Meier Survival Curve Analysis Kaplan Meier Survival Curve Analysis
Kaplan Meier Survival Curve Analysis Nermin Osman
 

What's hot (20)

Case control study
Case control studyCase control study
Case control study
 
Introduction to meta-analysis (1612_MA_workshop)
Introduction to meta-analysis (1612_MA_workshop)Introduction to meta-analysis (1612_MA_workshop)
Introduction to meta-analysis (1612_MA_workshop)
 
randomised controlled trial
randomised controlled trial randomised controlled trial
randomised controlled trial
 
Nested case control,
Nested case control,Nested case control,
Nested case control,
 
case control study
case control study case control study
case control study
 
Survival analysis
Survival analysisSurvival analysis
Survival analysis
 
Cohort studies..NIKHNA JAYAN
Cohort studies..NIKHNA JAYANCohort studies..NIKHNA JAYAN
Cohort studies..NIKHNA JAYAN
 
Chapter 2.2 screening test
Chapter 2.2 screening testChapter 2.2 screening test
Chapter 2.2 screening test
 
Case control study
Case control studyCase control study
Case control study
 
2-Epidemiological studies
2-Epidemiological studies2-Epidemiological studies
2-Epidemiological studies
 
Cross sec study dr rahul
Cross sec study dr rahulCross sec study dr rahul
Cross sec study dr rahul
 
Validity & reliability of screening & diagnostic tests
Validity & reliability of screening & diagnostic testsValidity & reliability of screening & diagnostic tests
Validity & reliability of screening & diagnostic tests
 
Cross sectional study
Cross sectional studyCross sectional study
Cross sectional study
 
Cohort Study
Cohort Study Cohort Study
Cohort Study
 
Case Study Control | Statistics
Case Study Control | StatisticsCase Study Control | Statistics
Case Study Control | Statistics
 
Bias and confounding
Bias and confoundingBias and confounding
Bias and confounding
 
Survival analysis & Kaplan Meire
Survival analysis & Kaplan MeireSurvival analysis & Kaplan Meire
Survival analysis & Kaplan Meire
 
Cohort ppt
Cohort pptCohort ppt
Cohort ppt
 
Kaplan Meier Survival Curve Analysis
Kaplan Meier Survival Curve Analysis Kaplan Meier Survival Curve Analysis
Kaplan Meier Survival Curve Analysis
 
Cross sectional study
Cross sectional studyCross sectional study
Cross sectional study
 

Similar to Case Control Study

Descriptive epidemiology
Descriptive epidemiologyDescriptive epidemiology
Descriptive epidemiologySonal Kale
 
Analytic upto surviellance
Analytic upto surviellanceAnalytic upto surviellance
Analytic upto surviellancekaleabtegegne
 
Study Design (Epidemilogical method)
Study Design (Epidemilogical method)Study Design (Epidemilogical method)
Study Design (Epidemilogical method)Dr. Animesh Gupta
 
PHARMACOEPIDEMIOLOGY
PHARMACOEPIDEMIOLOGYPHARMACOEPIDEMIOLOGY
PHARMACOEPIDEMIOLOGYAISHASID
 
Observational analytical and interventional studies
Observational analytical and interventional studiesObservational analytical and interventional studies
Observational analytical and interventional studiesAchyut Raj Pandey
 
presentation711-220325172711.pdf
presentation711-220325172711.pdfpresentation711-220325172711.pdf
presentation711-220325172711.pdfDanchadi
 
Observational study design
Observational study designObservational study design
Observational study designswati864887
 
Case Control Study (ANALYTICAL EPIDEMIOLOGY)
Case Control Study (ANALYTICAL EPIDEMIOLOGY) Case Control Study (ANALYTICAL EPIDEMIOLOGY)
Case Control Study (ANALYTICAL EPIDEMIOLOGY) Nidhi Singh
 
Analytical epidemiology seminar 3.pptx
Analytical epidemiology seminar 3.pptxAnalytical epidemiology seminar 3.pptx
Analytical epidemiology seminar 3.pptxdrmamatanaik
 
1_Intro to Research.pdf
1_Intro to Research.pdf1_Intro to Research.pdf
1_Intro to Research.pdfMharCastro
 
clinical trials types and design
clinical trials types and designclinical trials types and design
clinical trials types and designUttara Joshi
 
Seminar case control study
Seminar case control studySeminar case control study
Seminar case control studyRadhika Maniyar
 
Bias,confounding, causation and experimental designs
Bias,confounding, causation and experimental designsBias,confounding, causation and experimental designs
Bias,confounding, causation and experimental designsTarek Tawfik Amin
 
Study design of Epidemiology.pdf
Study design of Epidemiology.pdfStudy design of Epidemiology.pdf
Study design of Epidemiology.pdfNusrat Mim
 
4.1 case-control and cohort.pdf
4.1 case-control and cohort.pdf4.1 case-control and cohort.pdf
4.1 case-control and cohort.pdfmergawekwaya
 
3 Research methods and materials (1).pptx
3 Research methods and materials (1).pptx3 Research methods and materials (1).pptx
3 Research methods and materials (1).pptxestelaabera
 
# 5th lect clinical trial process
# 5th lect clinical trial process# 5th lect clinical trial process
# 5th lect clinical trial processDr. Eman M. Mortada
 

Similar to Case Control Study (20)

Descriptive epidemiology
Descriptive epidemiologyDescriptive epidemiology
Descriptive epidemiology
 
Analytic upto surviellance
Analytic upto surviellanceAnalytic upto surviellance
Analytic upto surviellance
 
Study Design (Epidemilogical method)
Study Design (Epidemilogical method)Study Design (Epidemilogical method)
Study Design (Epidemilogical method)
 
PHARMACOEPIDEMIOLOGY
PHARMACOEPIDEMIOLOGYPHARMACOEPIDEMIOLOGY
PHARMACOEPIDEMIOLOGY
 
Observational analytical and interventional studies
Observational analytical and interventional studiesObservational analytical and interventional studies
Observational analytical and interventional studies
 
5. Case control
5. Case control5. Case control
5. Case control
 
presentation711-220325172711.pdf
presentation711-220325172711.pdfpresentation711-220325172711.pdf
presentation711-220325172711.pdf
 
Observational study design
Observational study designObservational study design
Observational study design
 
Passive and active surveillance
Passive and active surveillancePassive and active surveillance
Passive and active surveillance
 
Case Control Study (ANALYTICAL EPIDEMIOLOGY)
Case Control Study (ANALYTICAL EPIDEMIOLOGY) Case Control Study (ANALYTICAL EPIDEMIOLOGY)
Case Control Study (ANALYTICAL EPIDEMIOLOGY)
 
Analytical epidemiology seminar 3.pptx
Analytical epidemiology seminar 3.pptxAnalytical epidemiology seminar 3.pptx
Analytical epidemiology seminar 3.pptx
 
1_Intro to Research.pdf
1_Intro to Research.pdf1_Intro to Research.pdf
1_Intro to Research.pdf
 
clinical trials types and design
clinical trials types and designclinical trials types and design
clinical trials types and design
 
Bias in clinical research
Bias in clinical research Bias in clinical research
Bias in clinical research
 
Seminar case control study
Seminar case control studySeminar case control study
Seminar case control study
 
Bias,confounding, causation and experimental designs
Bias,confounding, causation and experimental designsBias,confounding, causation and experimental designs
Bias,confounding, causation and experimental designs
 
Study design of Epidemiology.pdf
Study design of Epidemiology.pdfStudy design of Epidemiology.pdf
Study design of Epidemiology.pdf
 
4.1 case-control and cohort.pdf
4.1 case-control and cohort.pdf4.1 case-control and cohort.pdf
4.1 case-control and cohort.pdf
 
3 Research methods and materials (1).pptx
3 Research methods and materials (1).pptx3 Research methods and materials (1).pptx
3 Research methods and materials (1).pptx
 
# 5th lect clinical trial process
# 5th lect clinical trial process# 5th lect clinical trial process
# 5th lect clinical trial process
 

More from Dr. Animesh Gupta

Epidemiological Exercise.ppsx
Epidemiological Exercise.ppsxEpidemiological Exercise.ppsx
Epidemiological Exercise.ppsxDr. Animesh Gupta
 
Obesity & Metabolic syndrome
Obesity & Metabolic syndromeObesity & Metabolic syndrome
Obesity & Metabolic syndromeDr. Animesh Gupta
 
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...Dr. Animesh Gupta
 
Cancer II Epidemiology & Prevention of cancer
Cancer II Epidemiology & Prevention of cancerCancer II Epidemiology & Prevention of cancer
Cancer II Epidemiology & Prevention of cancerDr. Animesh Gupta
 
Malaria epidemiology, clinical features & treatment
Malaria epidemiology, clinical features & treatmentMalaria epidemiology, clinical features & treatment
Malaria epidemiology, clinical features & treatmentDr. Animesh Gupta
 
Cancer - Introduction, Control & Screening
Cancer - Introduction, Control & ScreeningCancer - Introduction, Control & Screening
Cancer - Introduction, Control & ScreeningDr. Animesh Gupta
 
Randomized Controlled Trial (RCT)
Randomized Controlled Trial (RCT)Randomized Controlled Trial (RCT)
Randomized Controlled Trial (RCT)Dr. Animesh Gupta
 
Descriptive Epidemiology (including Measurement in epidemiology)
Descriptive Epidemiology (including Measurement in epidemiology)Descriptive Epidemiology (including Measurement in epidemiology)
Descriptive Epidemiology (including Measurement in epidemiology)Dr. Animesh Gupta
 
Introduction to Epidemiology
Introduction to Epidemiology  Introduction to Epidemiology
Introduction to Epidemiology Dr. Animesh Gupta
 
Epidemiology - Introduction and Basic Measurement
Epidemiology - Introduction and Basic MeasurementEpidemiology - Introduction and Basic Measurement
Epidemiology - Introduction and Basic MeasurementDr. Animesh Gupta
 

More from Dr. Animesh Gupta (20)

Epidemiological Exercise.ppsx
Epidemiological Exercise.ppsxEpidemiological Exercise.ppsx
Epidemiological Exercise.ppsx
 
Poliomyelitis
PoliomyelitisPoliomyelitis
Poliomyelitis
 
Obesity & Metabolic syndrome
Obesity & Metabolic syndromeObesity & Metabolic syndrome
Obesity & Metabolic syndrome
 
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...
Dengue Syndrome (Dengue Fever, Dengue Haemorrhagic Fever & Dengue Shock Syndr...
 
Filariasis
FilariasisFilariasis
Filariasis
 
Cancer II Epidemiology & Prevention of cancer
Cancer II Epidemiology & Prevention of cancerCancer II Epidemiology & Prevention of cancer
Cancer II Epidemiology & Prevention of cancer
 
Malaria epidemiology, clinical features & treatment
Malaria epidemiology, clinical features & treatmentMalaria epidemiology, clinical features & treatment
Malaria epidemiology, clinical features & treatment
 
Cancer - Introduction, Control & Screening
Cancer - Introduction, Control & ScreeningCancer - Introduction, Control & Screening
Cancer - Introduction, Control & Screening
 
Randomized Controlled Trial (RCT)
Randomized Controlled Trial (RCT)Randomized Controlled Trial (RCT)
Randomized Controlled Trial (RCT)
 
Association and Causation
Association and CausationAssociation and Causation
Association and Causation
 
Descriptive Epidemiology (including Measurement in epidemiology)
Descriptive Epidemiology (including Measurement in epidemiology)Descriptive Epidemiology (including Measurement in epidemiology)
Descriptive Epidemiology (including Measurement in epidemiology)
 
Introduction to Epidemiology
Introduction to Epidemiology  Introduction to Epidemiology
Introduction to Epidemiology
 
Screening for disease
Screening for diseaseScreening for disease
Screening for disease
 
Rheumatic Heart Disease
Rheumatic Heart DiseaseRheumatic Heart Disease
Rheumatic Heart Disease
 
Epidemiology - Introduction and Basic Measurement
Epidemiology - Introduction and Basic MeasurementEpidemiology - Introduction and Basic Measurement
Epidemiology - Introduction and Basic Measurement
 
Tuberculosis
TuberculosisTuberculosis
Tuberculosis
 
Diabetes
Diabetes Diabetes
Diabetes
 
IMNCI
IMNCIIMNCI
IMNCI
 
NACP
NACPNACP
NACP
 
Epidemiologic transition
Epidemiologic transitionEpidemiologic transition
Epidemiologic transition
 

Recently uploaded

Trustworthiness of AI based predictions Aachen 2024
Trustworthiness of AI based predictions Aachen 2024Trustworthiness of AI based predictions Aachen 2024
Trustworthiness of AI based predictions Aachen 2024EwoutSteyerberg1
 
How to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyHow to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyZurück zum Ursprung
 
MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.whalesdesign
 
General_Studies_Presentation_Health_and_Wellbeing
General_Studies_Presentation_Health_and_WellbeingGeneral_Studies_Presentation_Health_and_Wellbeing
General_Studies_Presentation_Health_and_WellbeingAnonymous
 
Male Infertility Panel Discussion by Dr Sujoy Dasgupta
Male Infertility Panel Discussion by Dr Sujoy DasguptaMale Infertility Panel Discussion by Dr Sujoy Dasgupta
Male Infertility Panel Discussion by Dr Sujoy DasguptaSujoy Dasgupta
 
Generative AI in Health Care a scoping review and a persoanl experience.
Generative AI in Health Care a scoping review and a persoanl experience.Generative AI in Health Care a scoping review and a persoanl experience.
Generative AI in Health Care a scoping review and a persoanl experience.Vaikunthan Rajaratnam
 
High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)kishan singh tomar
 
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...Ganesan Yogananthem
 
Unit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptUnit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptPradnya Wadekar
 
The Importance of Mental Health: Why is Mental Health Important?
The Importance of Mental Health: Why is Mental Health Important?The Importance of Mental Health: Why is Mental Health Important?
The Importance of Mental Health: Why is Mental Health Important?Ryan Addison
 
Mental health Team. Dr Senthil Thirusangu
Mental health Team. Dr Senthil ThirusanguMental health Team. Dr Senthil Thirusangu
Mental health Team. Dr Senthil Thirusangu Medical University
 
historyofpsychiatryinindia. Senthil Thirusangu
historyofpsychiatryinindia. Senthil Thirusanguhistoryofpsychiatryinindia. Senthil Thirusangu
historyofpsychiatryinindia. Senthil Thirusangu Medical University
 
Red Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfRed Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfMedicoseAcademics
 
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.aarjukhadka22
 
Using Data Visualization in Public Health Communications
Using Data Visualization in Public Health CommunicationsUsing Data Visualization in Public Health Communications
Using Data Visualization in Public Health Communicationskatiequigley33
 
Adenomyosis or Fibroid- making right diagnosis
Adenomyosis or Fibroid- making right diagnosisAdenomyosis or Fibroid- making right diagnosis
Adenomyosis or Fibroid- making right diagnosisSujoy Dasgupta
 
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdf
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdfSGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdf
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdfHongBiThi1
 
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxBreast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxNaveenkumar267201
 
AUTONOMIC NERVOUS SYSTEM organization and functions
AUTONOMIC NERVOUS SYSTEM organization and functionsAUTONOMIC NERVOUS SYSTEM organization and functions
AUTONOMIC NERVOUS SYSTEM organization and functionsMedicoseAcademics
 
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfCONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfDolisha Warbi
 

Recently uploaded (20)

Trustworthiness of AI based predictions Aachen 2024
Trustworthiness of AI based predictions Aachen 2024Trustworthiness of AI based predictions Aachen 2024
Trustworthiness of AI based predictions Aachen 2024
 
How to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyHow to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturally
 
MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.
 
General_Studies_Presentation_Health_and_Wellbeing
General_Studies_Presentation_Health_and_WellbeingGeneral_Studies_Presentation_Health_and_Wellbeing
General_Studies_Presentation_Health_and_Wellbeing
 
Male Infertility Panel Discussion by Dr Sujoy Dasgupta
Male Infertility Panel Discussion by Dr Sujoy DasguptaMale Infertility Panel Discussion by Dr Sujoy Dasgupta
Male Infertility Panel Discussion by Dr Sujoy Dasgupta
 
Generative AI in Health Care a scoping review and a persoanl experience.
Generative AI in Health Care a scoping review and a persoanl experience.Generative AI in Health Care a scoping review and a persoanl experience.
Generative AI in Health Care a scoping review and a persoanl experience.
 
High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)
 
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...
QUESTIONS & ANSWERS FOR QUALITY ASSURANCE, RADIATIONBIOLOGY& RADIATION HAZARD...
 
Unit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptUnit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.ppt
 
The Importance of Mental Health: Why is Mental Health Important?
The Importance of Mental Health: Why is Mental Health Important?The Importance of Mental Health: Why is Mental Health Important?
The Importance of Mental Health: Why is Mental Health Important?
 
Mental health Team. Dr Senthil Thirusangu
Mental health Team. Dr Senthil ThirusanguMental health Team. Dr Senthil Thirusangu
Mental health Team. Dr Senthil Thirusangu
 
historyofpsychiatryinindia. Senthil Thirusangu
historyofpsychiatryinindia. Senthil Thirusanguhistoryofpsychiatryinindia. Senthil Thirusangu
historyofpsychiatryinindia. Senthil Thirusangu
 
Red Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfRed Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdf
 
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
 
Using Data Visualization in Public Health Communications
Using Data Visualization in Public Health CommunicationsUsing Data Visualization in Public Health Communications
Using Data Visualization in Public Health Communications
 
Adenomyosis or Fibroid- making right diagnosis
Adenomyosis or Fibroid- making right diagnosisAdenomyosis or Fibroid- making right diagnosis
Adenomyosis or Fibroid- making right diagnosis
 
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdf
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdfSGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdf
SGK LEUKEMIA KINH DÒNG BẠCH CÂU HẠT HAY.pdf
 
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxBreast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
 
AUTONOMIC NERVOUS SYSTEM organization and functions
AUTONOMIC NERVOUS SYSTEM organization and functionsAUTONOMIC NERVOUS SYSTEM organization and functions
AUTONOMIC NERVOUS SYSTEM organization and functions
 
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfCONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
 

Case Control Study

  • 1. Dr. Animesh Gupta MD,FDM,FAGE Associate Professor, Dept. of Community Medicine, NMCH, Sasaram (Bihar) 4/25/2020Case Control Study Dr Animesh Gupta 1
  • 2. At the end of the class, the students should know ▪ Different types of epidemiological methods ▪ Salient features of case control study ▪ Steps for conducting case control study ▪ Matching ▪ Odds ratio ▪ Bias in case control study ▪ Advantages & disadvantages in case control study 4/25/2020Case Control Study Dr Animesh Gupta 2
  • 3. OBSERVATIONAL STUDIES DESCRIPTIVE STUDY ANALYTICAL STUDIES ✓ TIME ✓ PLACE ✓ PERSON ➢ ECOLOGICAL STUDY ➢ CROSS SECTIONAL STUDY ➢ CASE-CONTROL STUDY ➢ COHORT STUDY EXPEREMENTAL STUDIES ➢ RANDOMIZED CONTROLLED TRIAL (RCT) ➢FIELD TRIAL ➢COMMUNITY TRIAL 4/25/2020Case Control Study Dr Animesh Gupta 3
  • 4. ▪Makes careful measurement of patterns of exposure and disease in population ▪Comparison group ▪The object is not to formulate but to test the hypothesis. ▪To evaluate an association between exposure and disease. 4/25/2020Case Control Study Dr Animesh Gupta 4
  • 5. ▪The observational epidemiologic study of persons with the disease (or other outcome variable) of interest and a suitable control (comparison/ reference) group of persons without the disease. (- John M Last) ▪It is an observational study in which subjects are sampled based upon presence or absence of disease and then their prior exposure status is determined. 4/25/2020Case Control Study Dr Animesh Gupta 5
  • 6. ▪ Also knowns as “retrospective study” ▪ From effect to cause ▪ The case control method has three distinct features: ▪ Both exposure and out come have occurred before the start of the study. ▪ The study proceeds backwards from effect to cause. ▪ It uses a control or comparison group to support or refute an inference. 4/25/2020Case Control Study Dr Animesh Gupta 6
  • 7. 4/25/2020Case Control Study Dr Animesh Gupta 7
  • 8. 1. Selection of cases and controls 2. Matching 3. Measurement of exposure 4. Analysis & interpretation 4/25/2020Case Control Study Dr Animesh Gupta 8
  • 9. ▪Study begins with cases, i.e. the patients in whom the disease has already occurred. ▪Cases were enquired for all the details of their exposure to the suspected cause. ▪Definition of case: ▪ Diagnostic criteria : Clear cut diagnostic criteria of the disease and its stage. ▪ Eligibility criteria : It is always advisable to take the incident cases,since the prevalent cases might have changed their exposure status due to medical advice etc. 4/25/2020Case Control Study Dr Animesh Gupta 9
  • 10. ▪Sources of Cases ▪ Hospitals ▪ Single hospital or a network of hospitals, admitted during a specified period of time. ▪ The entire case series or a random sample of it is selected for study. ▪ General population ▪ Defined geographic area during a specified period of time ▪ Can be taken data through a survey, a disease registry or hospital network. ▪ The cases should be fairly representative of all cases in the community. 4/25/2020Case Control Study Dr Animesh Gupta 10
  • 11. ▪ Controls must be free from disease ▪ Must be similar to the cases as far as possible except for the absence of disease. ▪ Sources: ▪ Hospital control ✓Different illness other than the study disease ▪ Relatives ✓Except genetic condition study ▪ Neighborhood ✓Same locality/ working in same area/factory ▪ General population ✓Defined geographic areas 4/25/2020Case Control Study Dr Animesh Gupta 11
  • 12. ▪Select controls from various diagnostic groups, so no particular risk factors will be over represented ▪Select controls from patients with acute conditions, so earlier exposures could not have been influenced by the condition ▪Do not select patients who have multiple concurrent conditions. ▪Do not select patients with diagnoses known to be related to the risk factor of interest 4/25/2020Case Control Study Dr Animesh Gupta 12
  • 13. ▪ Matching is the process of selecting controls who are similar to the cases in certain key characteristics (eg.age,sex,race) which are known to influence the outcome of the disease. ▪ Individual matching (matched pair) ▪ for each case, a control is selected who is similar to the case for a given variable ▪Group matching (frequency matching) ▪ proportion of controls with a given characteristic (variable) is identical to proportion of cases with the same characteristic 4/25/2020Case Control Study Dr Animesh Gupta 13
  • 14. ▪Defined as one which is associated both with exposure and disease and is distributed unequally in study and control groups. ▪Alcohol & Oesophageal cancer study – smoking is a confounding factor. 4/25/2020Case Control Study Dr Animesh Gupta 14
  • 15. To find out ▪Exposure rate among cases and controls to suspected factor. ▪Estimation of disease risk associated with exposure (Odds ratio). 4/25/2020Case Control Study Dr Animesh Gupta 15
  • 16. Cases Controls Risk factor + a b Risk factor -- c d 4/25/2020Case Control Study Dr Animesh Gupta 16
  • 17. ▪Among cases = a/a+c ▪Among controls = b/b+d 4/25/2020Case Control Study Dr Animesh Gupta 17
  • 18. ▪Odds = is the ratio of the probability that an event will happen to the probability that it will not happen ▪Odds ratio / cross product ratio = ad/bc ▪It interprets that odds of cases being exposed are so many times higher compared to the odds of controls being exposed. 4/25/2020Case Control Study Dr Animesh Gupta 18
  • 19. ▪Based on 3 assumption that ▪Disease being investigated must be relatively rare. In fact majority of the chronic disease have a low incidence in the general population. ▪The cases must be representative of those with the disease. ▪The controls must be representative of those without the disease. 4/25/2020Case Control Study Dr Animesh Gupta 19
  • 20. It is systematic error in the determination of the association between the exposure and the disease. ▪Bias due to confounding factor ▪Memory or recall bias ▪Selection bias ▪Interviewer’s / Observer bias ▪Berkesonian bias ( Dr Joseph Berkeson) ▪ Different rates of admission to the hospital with different disease. 4/25/2020Case Control Study Dr Animesh Gupta 20
  • 21. Strength ▪ Good for examining rare outcomes or outcomes with long latency ▪ Relatively quick to conduct, inexpensive ▪ Requires comparatively few subjects ▪ Multiple exposures or risk factors can be examined. Weakness ▪ Bias ▪ Selection of an appropriate control group may be difficult ▪ Incidence cant be calculated ▪ Do not distinguish between causes and associated factors 4/25/2020Case Control Study Dr Animesh Gupta 21
  • 22. ▪It is usually conducted before a Cohort or Experimental Study to identify the possible etiology of the disease. ▪ It costs relatively less and can be conducted in a shorter time ▪For a given disease, a case control study can investigate multiple exposures (when the real exposure is not known) ▪Case control study is preferred when the disease is rare because investigator can intentionally search for the cases. 4/25/2020Case Control Study Dr Animesh Gupta 22
  • 23. Thank You 4/25/2020Case Control Study Dr Animesh Gupta 23