EPIDEMIOLOGICAL METHODS PPT.pptx

EPIDEMIOLOGICAL METHODS IS AN IMPORTANT TOPIC ON THE SUBJECT ADVANCED NURSING PRACTICE FOR PG STUDENTS OF NURSING

1. PRESEN TED BY Tapaswinee Swain SEMINAR ON EPIDEMIOLOGICAL METHODS SUBJECT - (Advanced Nursing Practice)  

2. CONTENTS INTRODUCTION DEFINITION TERMS EPIDEMIOLOGICAL METHODS CLASSIFICATION OF EPIDEMIOLOGICAL METHODS RESEARCH ABSTRACT ROLE OF NURSE IN EPIDEMIOLOGY SUMMARY CONCLUSION BIBLIOGRAPHY

3. Epidemiology is the basis of preventive and social medicine .It not only helps to understand the health and disease concept, & determinants, but also help in planning, implementing & evaluating health services. The term is derived from Greek word i.e. epi (upon), demos (the people), logos (study) . So , it means the knowledge and study of anything that comes upon or affects people. INTRODUCTION

4. According to Parkin 1873 ; Epidemiology is that branch of medical science which deals with epidemics. According to Clark 1965 ; Epidemiology is the study of various factors & conditions that determine the occurrence and distribution of health, disease, defect, disability & death among groups of individuals. According to Frost 1927 ; Epidemiology is the science of mass phenomena of infectious diseases. DEFINITIONS

5. Epidemic : An outbreak of disease in a community in excess of normal expectation . Endemic : The constant presence of disease or infectious agent with in a geographical area or population group. Pandemic : An epidemic which spreads from country to country or over the whole world. Sporadic : The cases occur irregularly and haphazardly from time to time.

6. The primary concern of the epidemiologist is to study disease occurrence in people. Epidemiological study requires systematic collection of data regarding health, its analysis, description of health needs and health problems, identification of factors associated with the problems. EPIDEMIOLOGICAL METHODS

7. CLASSIFICATION OF EPIDEMIOLOGICAL METHODS

8. Observation is a way of gathering data by watching behavior or events. The researchers simply "observe" a group of people without "doing" anything to the study group. Example:- There are several situations that require nurses to use the observation method for data collection, such as behavior & attributes of the patients, their families, hospital staff, & so on. OBSERVATIONAL STUDIES

9. CARE ( Consortium for Academic Research and Ethics journals created by UGC )   Research abstract on Observational Study:- An observational study of adherence to home nebulizer therapy among children with asthma. Published online 2021 Feb 4 Deyu Zhao, Dehui Chen, Ling Li, YingXue Zou , Yunxiao Shang, Chonglin Zhang, Li Zhang, Jiahua Pan, Qiang Chen, Tao Ai, and Qian Ni Background: The prevalence of pediatric asthma in China is approximately 3%, and asthma remains poorly controlled in many of these patients. This study assessed the rate of adherence to home nebulizer treatment in pediatrics patients in China . Methods: The CARE study was a 12-week, multicentre, prospective, observational study across 12 tertiary hospitals in China. Patients were aged 0–14 years, clinically diagnosed with asthma and prescribed home nebulizer inhaled corticosteroid (ICS) therapy for ⩾3 months. The primary endpoint was electronically monitored treatment adherence. Patients attended onsite visits at 0, 4, 8 and 12 weeks to assess asthma control, severity and treatment adherence (recorded by electronic monitoring devices and caregivers).

10. CARE ( Consortium for Academic Research and Ethics journals created by UGC )   Results: The full analysis set included 510 patients. Median treatment adherence reported by electronic monitoring devices was 69.9%, and median caregiver-reported adherence was 77.9%. The proportion of patients with well-controlled asthma increased from 12.0% at baseline to 77.5% at visit 4. Increased time between asthma diagnosis and study enrolment was a significant predictor for better adherence [coefficient: 0.01, p = 0.0138; 95% confidence interval (CI): 0.00, 0.01] and asthma control (odds ratio = 1.001, p = 0.0498; 95% CI: 1.000, 1.002). Negative attitude to treatment by the caregiver was associated with poorer asthma control. Conclusions: Adherence to home nebulization, a widely used treatment for asthma, was high among Chinese pediatric patients. Asthma control improved with increasing treatment duration. These results suggest that home nebulization of ICS is an effective and recommendable long-term treatment for pediatric patients with asthma.

11. Descriptive epidemiology is the first phase of epidemiological investigation. The study concerns with observing the distribution of disease or health related characteristics in human population and identifying the characteristics with which the disease in question seems to be associated. This method gives information about: - Who all are affected by a particular disease or health related problems, Where the cases occur, When it occur. DESCRIPTIVE STUDY

12. CHARACTERISTICS Time : Year, season, month, week, day, hour of onset. Place: Climatic zone, country, region (urban, rural & local community), town, cities, institution etc. Person: Age, sex, marital status, occupation, social status, education etc.

13. STEPS

14. DEFINING THE POPULATION The defined population needs to be large enough so that age, sex & other specified rate are meaningful. The community should be stable, without migration into & out of area. The defined population can be selected group such as age & sex- group, hospital patients, school children etc.

15. DEFINING THE DISEASE UNDER STUDY Once the population to be studied is fixed, the epidemiologist focus on the disease being investigated. So his concerned is to obtain an accurate, precise & valid definition of the disease. It is called as the operational definition.

16. DESCRIBING THE DISEASE BY TIME PLACE AND PERSON TIME DISTRIBUTION : The disease rate may vary by the time of its occurrence i.e. by week , month, year etc .

17. Three kinds of time trends of disease occurrence: Short term fluctuations : Common source epidemics - well of contaminated water; food poisoning. Propagated epidemics - person to person, arthropod vector, animal reservoir. E.g. Hepatitis A. Slow modern epidemics - road accidents, blood cancer, hypertension .

18. PLACE DISTRIBUTION Geographic pattern provides data regarding the cause of the disease. The geographic distribution of the disease varies because of variation in cultures , standard of living and external environments. The variations can be: International variations National variations Rural - urban variations Local distributions

19. PERSON DISTRIBUTION The disease should be described by age, sex, marital status, ethnicity, occupation, social class, behavior, other host factors etc.

20. MEASUREMENT OF DISEASE After defining the disease, the disease load should be measured in population. Disease should be measured in terms of mortality, morbidity, disability and so on. Morbidity has 2 aspects - prevalence and incidence .

21. COMPARING WITH KNOWN INDICES Comparisons between different populations, groups, sub groups. It is possible to arrive at clues to disease etiology.

22. FORMULATION OF AN ETIOLOGICAL HYPOTHESIS The descriptive epidemiology helps to formulate hypothesis relating to disease etiology. An epidemiological hypothesis should specify: The population The specific cause The expected outcome The dose response relationship The time response relationship

23. USES OF DESCRIPTIVE EPIDEMIOLOGY It provides data regarding the magnitude of disease load and types of disease problem. It provides clue to disease etiology. It provides data for planning, organizing and evaluating the preventive services. It contributes to research by describing variations.

24. ANALYTICAL STUDY This is the second major type of epidemiological studies. The subject of interest in analytical studies is an individual with in the population. It comprises of four (4) distinct types of observational studies i.e. Cross sectional study Ecological study Case control study Cohort study

25. CROSS SECTIONAL STUDY It is the simplest form of an observational study. It is based on single examination of cross-section of population at one point of time- the result of which can be projected on the whole population. Cross-section studies are more useful for chronic disease. We can also collect data during the survey about age, sex, physical exercise, body weight, salt intake and other variable of interest.  e.g. A medical study examining the prevalence of cancer amongst a defined population. The researcher can evaluate people of different ages, ethnicities, geographical locations, and social backgrounds.

26. ECOLOGICAL STUDY An ecological study is an observational study defined by the level at which data are analyzed, namely at the population or group level, rather than individual level. Ecological studies are often used to measure prevalence and incidence of disease, particularly when disease is rare. They are inexpensive and easy to carry out, using routinely collected data but they are prone to bias

27. DIET AND CANCER [https://en.wikipedia.org/wiki/Ecological_study] Dietary risk factors for  cancer  have also been studied using both geographical and ecological studies. Multi-country ecological studies of cancer incidence and mortality rates with respect to national diets have shown that some dietary factors such as animal products (meat, milk, fish and eggs), added sweeteners/sugar, and some fats appear to be risk factors for many types of cancer, while cereals/grains and vegetable products as a whole appear to be risk reduction factors for many types of cancer.

28. CASE - CONTROL STUDY/ RETROSPECTIVE STUDY Case - Control Study involves two populations: case & control. In Case - Control Studies, the unit is an individual rather than a group. The focus is on a disease or some health problem that has already developed. These studies are basically comparison studies. For e.g. one can use immunized children as case & unimmunized children as control & look for the factors of interest in their past histories. e.g. Study to determine an association between salmonella infection & eating at a first food restaurant

29. DISTINCT FEATURES Both exposure and outcome have occurred before the start of the study. The study proceeds backward from effect to cause. It uses a control or comparison group to support or refute an inference.

30. Basic factors in conducting a Case - Control Study

31. Selection of cases and controls The first step is to identify a suitable group of cases and group of controls . The case may be drawn from hospitals & general population. The control must be free from the disease under study.

32. MATCHING Matching is defined as the process by which we select control in such a way that they are similar to cases in regards to certain pertinent selected variables; if not adequately matched, could distort or confound the result. There are several kinds of matching procedures like Group matching may be done by assigning cases to subcategories based on their characteristics

33. Measurement of exposure Information about exposure should be obtained in precisely the same manner, both for the cases and controls. This may be obtained by interviews, by questionnaires or by studying the past record.

34. Analysis and Interpretation Final step in analysis is to find out: Exposure rates among cases & controls. Estimation of risk associated with exposure. a. Exposure rates - A case-control study provides a direct estimation of exposure rates to a suspected factor in a diseased and non-diseased group. b. Estimation of risk - The estimation of risk associated with exposure is obtained by an index known as “relative risk”, which is defined as the ratio between incidence of disease among exposed persons and incidence among non-exposed.

35. ADVANTAGES: Inexpensive Require fewer subjects Easy Minimal ethical problem Can check for more than one risk factor No risk to subjects DISADVANTAGES: Information not easily available Difficult to validate Bias in selection Not suited for evaluation of therapy or prophylaxis Don’t distinguish between the cause and associated factor

36. COHORT STUDY Other names are: Prospective study, longitudinal study, incidence study, forward -looking study. The cohort study is concerned with frequency of disease in exposed and non-exposed individuals. This study design is used to investigate the causes of disease and to establish links between risk factors and health outcomes. E.g., A researcher observes the smoker for development of lung cancer.

37. CONCEPT OF COHORT Cohort is defined as a group of people who share a common characteristic or experience within a defined period of time. E.g.- A group of people born on the same day or same period of time make a birth cohort, like wise age cohort, educational cohort, occupational cohort etc.

38. DISTINCT FEATURES

39. INDICATIONS FOR COHORT STUDY When there is good evidence of association between exposure & disease. When the exposure is rare, but the incidence of the disease is high among the exposed. When attribution of study population can be minimized. When ample funds are available.

40. TYPES OF COHORT STUDY

41. Prospective C.S - It is the one in which the outcome has not yet occurred at the time the investigation begins. Retrospective C.S - It is the one in which outcome has all occurred before the start of the investigation. Mixed/Combination of both - In this type of study both Prospective & Retrospective elements are combined.

42. STEPS OF COHORT STUDY

43. ANALYSIS OF COHORT STUDY Cigarette smoking Developed lung cancer Did not develop lung cancer Total Yes 70 6930 7000 No 03 2997 3000 Data are analysed in terms of Incidence rate of outcome among exposed and non-exposed e.g. Cigarette smoking & lung cancer  Among smokers : 70/7000 = 10 per 1000 Among non-smokers : 3/3000 = 1 per 1000  

44. ADVANTAGES:- Incidence can be calculated. Several possible outcomes related to exposure can be studied. Provide direct estimate of related risk. Bias can be minimized. DISADVANTAGES:- Involve large no. of people. Expensive. Unsuitable for investigating uncommon diseases. Takes long time to complete study and obtain results. Administrative problems : funding. Study may itself alter cohort’s behaviour.

45. EXPERIMENTAL STUDIES Experimental studies, commonly referred to as clinical trials, are studies in which a treatment or procedure is intentionally introduced by the epidemiologist and a result or outcome is observed. It’s the most scientifically sophisticated research

46. The aims of experimental studies To provide scientific proof of etiological factors which may permit the modification or control of those studies . To provide a method for measuring the effectiveness & efficiency of health services for prevention, control & treatment of disease & improve the health of community.

47. TYPES OF EXPERIMENTAL STUDIES

48. RANDOMIZED CONTROL TRIALS Development of an assessment method, known as RCT. In this type, the people being studied are randomly allocated one or other of the different treatments under study. It is really an epidemiological experiment. RCT is a gold standard for clinical trial.

49. STEPS/DESIGN IN CONDUCTING RCT

50. The protocol specifies : goal and objectives of the study , Criteria & preparation of questions to be answered for selected study group and control group , Size of the sample, Treatment to be applied – when, where & to what kind of patients . Drawing up a protocol

51. Selection of reference and experimental population 1 . Reference or Target population: It is the population to which the findings of the trial are expected to be applicable. A reference population may be as mankind in specific age, sex, occupation or social groups. 2 . Experiment or Study population: It is derived from the reference population. It is actual population that participates in experimental study.

52. Randomization It is a statistical procedure by which the participants are allocated into groups called study and control groups. Randomization is an attempt to eliminate bias and allow for comparability. Every individual gets an equal chance of being allocated into group.

53. Manipulation Having formed the study and control group, the next step is to intervene or manipulate the study group by deliberate application or withdrawal or reduction of casual factor as laid down in the protocol. This manipulation creates an independent variable whose effect is then determined by measurement of final outcome which constitute the dependent variable.

54. Follow up - This implies examination of experimental & control group subjects at definite interval of time in a standard manner of time, under the same frame until the final outcome has determined . Assessment of outcome - The final step is the assessment of outcome of trial in terms of : Positive result Negative result.

55. NON-RANDOMIZED TRIALS Due to ethical, administrative and cost; it is not always possible to resort to randomized controlled trials. This approach is crude. As there is no randomization, degree of comparability is low and chances of spurious results will be high . E.g. Useful to known whether specific therapy is valuable for particular disease, to determine the appropriate dose, to investigate adverse reactions.

56. Merits - Scientifically ideal method. Removes a large no. of biases. Builds up ‘faith’ in the findings of the study. Ensures temporal relationships between exposure and outcome. Demerits - Need long time. Have ethical issues. Expensive.

57. FIELD TRIALS The field trial is the one such type of interventional study designed to evaluate prevention strategies. This studies are carried out “on the ground” or “on the field”, in people not admitted to an institution but in subjects of the population, free of disease. Here we evaluate whether an intervention reduces the risk of developing a disease . They are carried out to people who do not necessarily have a particular disease but are considered at risk. Example , One of the largest field trials was that testing the Salk vaccine for the prevention of poliomyelitis, which involved over one million children.

58. COMMUNITY TRIALS Community trials, also called community intervention studies, are mostly preventive experimental studies with whole communities such as cities or states as experimental units; that is, interventions are assigned to all members in each of a number of communities. Community trials are an extension of the field trials; and are  field trials  in which the totality of the community are the units of assignment . Example:-The effectiveness of fluoride in preventing dental caries was tested comparing the frequency of caries in the children in Kingston and Newburgh.03-May-2016

59. ROLE OF NURSE IN EPIDEMIOLOGY :- She makes use of nursing process which is comparable to epidemiological process in solving the problem. She identifies the problem, formulates intervention and evaluate the effectiveness of intervention. She play active role in the prevention and control of communicable diseases. Community health nurse can also teach and supervise other workers in surveillance activities. She may participate as the team members. She participates in national programs. She participates in data collection, data analysis, planning, implementation and evaluation.  

60. SUMMARY

61. CONCLUSION Epidemiology is an valuable tool for providing the rational basis on which effective prevention programmes can be planned and implemented and for conducting clinical investigations that contribute to the control of the disease and to the improvement of the human suffering associated with it.

62. BIBLIOGRAPHY Suresh k Sharma. Text book of Nursing Research & statistics, 2 nd Edition. Elsevier publication, 2011. Navdeep Kaur Brar, HC Rawat, “Textbook of Advanced Nursing Practice”, 3 rd edition Delhi: Jaypee Publication; 2017 Samta Soni, “Textbook of Advanced Nursing Practice”, 1 st edition Jaypee Publication; 2013 Shebeer. P. Basheer, S. Yaseen Khan“A concise Textbook of Advanced Nursing Practice”, 1 st edition Emmess Publication; 2012 https://www.nature.com/articles/6400454.pdf?origin=ppub#:~:text=An%20ecological%20study%20is%20an,particularly%20when%20disease%20is%20rare . https://sphweb.bumc.bu.edu/otlt/mph-modules/ep/ep713_clinicaltrials/EP713_ClinicalTrials2.html#:~:text=A%20well%2Dknown%20type%20of,children%20in%20Kingston%20and%20Newburgh . https://www.medwave.cl/link.cgi/English/Perspectives/LettersToEditor/6814#:~:text=Field%20trials%20are%20studies%20carried,2%5D%2C%5B3%5D . https://www.slideshare.net/keshabchapagain2/epidemiology-ppt-37486620 https://webcache.googleusercontent.com/search?q=cache:-ijoAta3VBwJ:https://microbenotes.com/field-trials/+&cd=11&hl=en&ct=clnk&gl=in https://www.slideshare.net/pramodkumarsikarawar/epidemiology-66624986