Epidemiologi secara formal didefinisikan dalam beberapa arti. Pertama, epidemiologi adalah ilmu yang mempelajari distribusi dan faktor-faktor penentu penyakit dan cedera dalam populasi manusia (Mausner and Kramer, 1985). A Definisi kedua menekankan studi tentang semua faktor yang mempengaruhi terjadinya kesehatan dan penyakit dalam populasi dan saling ketergantungan diantara mereka. Akhirnya, epidemiologi adalah ilmu yang mempelajari distribusi dan faktor-faktor penentu kesehatan yang berhubungan dengan negara dan peristiwa dalam populasi tertentu dan aplikasi ilmu ini untuk mengendalikan masalah kesehatan (Last, 1995).
Pada awal abad ke dua puluh satu, epidemiologi telah mulai memperluas fokusnya pada status kesehatan, kualitas kesehatan yang berhubungan dengan kehidupan, dan beban penyakit. Sebagai akibat serangan teroris di Amerika Serikat pada tanggal 11 September 2001, epidemiologi telah mengambil peran baru dalam kesiapsiagaan bioterorisme dan manajemen pelayanan kesehatan. Dengan munculnya penyakit menular dalam yang jumlah signifikan (termasuk AIDS dan SARS), peran awal epidemiologi dalam studi epidemi akan kembali menonjol
Epidemiologi dan pengobatan selalu dikaitkan sebagai disiplin ilmiah. Epidemiologi merupakan perangkat yang penting dari kesehatan masyarakat dan kedokteran pencegahan. Penggunaan tertentu epidemiologi termasuk menentukan etiologi atau faktor penyebab penyakit; menjelaskan faktor-faktor yang berkaitan dengan kondisi yang merugikan; diagnosis distribusi penyakit dalam komunitas; memprediksi terjadinya, dampak, dan distribusi penyakit; memperkirakan risiko seseorang menderita penyakit; mengevaluasi kegiatan intervensi pencegahan dan terapeutik; mengukur keberhasilan tindakan kesehatan; mempelajari sejarah tren penyakit; identifikasi sindrom penyakit; perencanaan untuk kebutuhan kesehatan saat ini, dan memprediksi kebutuhan masa depan.
Status kesehatan populasi secara keseluruhan adalah perhatian penting dari perawatan kesehatan di model manajemen perawatan kesehatan penduduk.Memahami pola kesehatan dan penyakit dalam populasi memungkinkan untuk perencanaan yang tepat untuk layanan dan program untuk memenuhi kebutuhan layanan kesehatan yang sah perawatan kesehatan Kontemporer harus bisa memperoleh data dan memahami masyarakat dengan melakukan studi investigasi mereka sendiri pada populasi dilayani. Pengetahuan tersebut akan penting untuk profitabilitas
data epidemiologi dan informasi akan menjadi penting bagi manajer perawatan kesehatan. data epidemiologi telah menjadi sumber yang berguna untuk informasi yang dapat menuntun keputusan-keputusan manajerial dan outcome. Data epidemiologi diperlukan untuk rencana dan desain sistem perawatan kesehatan, yang didasarkan pada masyarakat dan kelompok masyarakat.Pengetahuan tentang epidemiologi dan pemahaman data epidemiologi adalah persyaratan dasar untuk perawatan kesehatan sukses
What types of epidemiogical study are there? Generally epidemiological studies are used to provide information on three areas: 1.on the distribution and frequency of diseases, and on the frequency and distribution of known and possible causes of diseases in populations – such studies are usually called descriptive;
2.on the strength of associations between diseases and other factors (such as smoking, diet or socio-economic status), with particular emphasis on whether such associations are causal – such studies are usually called analytical; 3.on whether interventions aimed at preventing a disease or improving its outcome actually do so – such studies are usually called intervention studies.
What are intervention studies used for and what types are there? The key difference between analytical and intervention studies is this: in an analytical study the investigator simply observes the exposure status of individuals; in an intervention study the investigator intervenes to change the exposure status of individuals to determine what happens when this is done
Clinical trials In a clinical trial one group of individuals receive an intervention and are compared to another group who do not receive the intervention. Clinical trials are often divided into two types: therapeutic or secondary prevention trials, and preventive or primary prevention trials. intervention studies
Therapeutic trials are conducted among patients with a particular disease or health problem to determine the ability of an intervention (such as a drug, changes in diet, or psychological counselling) to reduce symptoms, prevent recurrence, or decrease the risk of death from that disease. A preventive trial is used to evaluate whether an intervention reduces the risk of developing a disease among those who are free from it when they enter the trial.
Community Trial In a community trial the units of study are communities rather than individuals. This is particularly appropriate for diseases that have their origins in social, cultural or environmental conditions, where it makes sense to try and change these conditions on a community-wide basis rather than an individual basis. For example, a community trial aimed at changing diet might include widespread information campaigns using the local media, as well as measures to increase the availability of healthy foods in the local shops. intervention studies
Health status health has been traditionally measured as ill health and its severe manifestations. Health status is a term that describes a measurement of health for a population. Health status has become a multidimensional construct (Patrick and Erickson, 1993). The dimensions of health status include premature mortality, disease symptoms, physiologic states, physical functions, emotional functions, cognitive functions, and health perceptions.
Health status is measured by many different scales and indices that attempt to combine the impact of morbidity and mortality. Health status is typically a measure of the extent to which an individual can function physically, mentally, socially, and emotionally.
Descriptive data offer essential information regarding health, disease, and disease patterns, illuminating disease patterns in terms of person, place, and time. Descriptions of who is affected, where the disease occurs, and when it occurs indicate factors possibly responsible for high or low frequencies of disease in specific groups of individuals. Descriptive data can help identify both high-risk groups of individuals for future interventions and problems to be studied by formal analytic methods. DESCRIPTION OF HEALTH
In addition to aiding in these public health efforts, descriptive data are important to health care administrators because they provide a basis for planning, designing, operating, and evaluating health services. Data describing trends in health and disease provide knowledge about the need and potential demand for health services in populations that is fundamental to effective planning.
Descriptive data occur in two forms—primary and secondary. Primary data are directly collected by a researcher for specific research needs and objectives. The quality of such data is carefully controlled, because data collection is designed to meet the needs of a specific study. Primary data are collected in both large populations and subpopulations. Primary data collection can be time-consuming, expensive, and difficult to accomplish effectively. Descriptive Data
Descriptive information is typically collected according to person, place, and time. These parameters are described by several measurable variables that indicate health and disease patterns across and within populations and communities.
Secondary data are collected, usually on a routine basis, by such groups as local, state, national, and international health care agencies. Although they are less expensive and easier to obtain than primary data, secondary data have inherent disadvantages and are often incomplete or inaccurate. Recording and presentation of secondary data can be inconsistent due to the varying methods of data collection used by different collectors. Specific information may be missing, and information may not be recorded in the desired format. Secondary data are typically released several years after being collected.
MEDICAL MANAGEMENT IN POPULATION HEALTH CARE Clinical Effectiveness – Clinical effectiveness is a concept that investigates the appropriate use of clinical resources: whether tests and treatment are selected appropriately, based on diagnoses. To determine clinical effectiveness, the following questions must be answered: Are the tests accurate? Are the resources used appropriately? What is the impact of testing information? What is the diagnostic ability of the tests?
Accuracy, efficacy, and efficiency are indicators of test performance. Accuracy is defined as the condition of being true, correct, or exact; efficacy is the capacity of producing a desired result or effect (or effectiveness); and efficiency is the ability to accomplish a job with a minimum expenditure of time and effort
Validity is the construct that measures the accuracy of a test. By accuracy, we mean how often a test correctly identifies individuals with and without a disease. Validity is also thought of as the ability of a test to produce a true measure. Validity is quantified by the parameters known as sensitivity, specificity, and predictive values (of positive and negative test results).
Validity parameters are determined by using a 2-by-2 contingency table
Sensitivitas : kemampuan untuk mengidentifikasi individu yang menderita penyakit secara benar, (positif sejati). Spesifisitas : kemampuan untuk mengidentifikasi individu yang tidak menderita penyakit secara benar (negatif sejati). Berkaitan dengan kemampuan tes tersebut untuk mengukur apa yang seharusnya diukur (membedakan individu yang sakit dengan individu yang tidak sakit) Tes sensitivitas dan tes spesifisitas merupakan ukuran validitas
The presumptive identification of unrecognised disease or defect by the application of tests, examinations or other procedures which can be applied rapidly. Screening tests sort out the apparently well persons who probably have a disease from those who probably do not. (Last and Spasoff 2000: 118)
Why did screening develop? – When initially introduced into health care, screening only really extended the therapeutic range. This was obviously based on the idea that the outcome could potentially be improved if a disease process could be identified and treatment started at an early stage.
Early Intervention in the Natural History of Disease HEALTH OUTCOMES Cure Control Disability Death Disease Onset SymptomsDiagnosisTherapy Care Seekin g Good Health Early detection through Screening
Comparison between screening and diagnostic tests Diagnostic tests Screening tests Done to those with suggestive signs or symptoms Done to those who are apparently healthy or asymptomatic Applied to a single person Applied to a group of individuals Results are based on the evaluation of a number of symptoms, signs and investigations Results are based on one criterion Results are conclusive and finalResults are not conclusive More accurateLess accurate More expensiveLess expensive Basis for treatmentNot a basis for treatment
Diseases for which screening has been recommended Cervical cancer Breast cancer Ovarian cancer Colorectal cancer Skin cancer Diabetes Hypertension
More Conditions for Which Screening Is Recommended Health Outcome Test(s) Populations(s) Age Group (years) Obesity CVD/HBP CVD Injury/Liver disease Colorectal cancer Breast cancer Cervical cancer Chlamydia Gonorrhea Syphilis Height/Weight Blood pressure Cholesterol Alcohol overuse Fecal Occult Blood Test Sigmoidoscopy Mammography /Clinical Breast Exam Pap Smear Lab General General/HR6 General General/HR4 HR2 HR1/HR9 All 25-64/65+ 11+ 25+ 50+ (female) 11+ (female) 11-24/11-64 11-24, 25-64 11-64/65+ Source: U.S. Preventive Services task Force [USPSTF] (1996)
Understanding population characteristics is important because health and disease patterns are identified with respect to the “population at risk” or, in this case, the population to be served. Health and disease trends are expressed as epidemiologic measures, that is, rates and ratios, with geographic and demographic bounds
Measuring the Quality of Health Care The measurement and improvement of quality of care have been a part of health care for decades. Recently, attempts to measure and monitor quality have become more intense as a response to demands for accountability in the delivery of services (Relman 1988) and as an outgrowth of the quality and outcomes "movement."
Measuring Quality: Structure, Process, Outcome Quality of care can be measured based on structure, process, or outcome (Donabedian 1980,1982,1985). Structural measures are the characteristics of the resources in the health system. Processes embody what is done to and for the patient (e.g., ordering of a immunization, prescription of a medication). Process measures of quality can be made for individual practitioners, groups of practitioners, or for entire systems of care
Outcomes are the end results of care or the effect of the care process on the health and well-being of patients and populations. Elinson (1987) describes the relevant health care outcomes as "the five Ds"—death, disease, disability, discomfort, and dissatisfaction Measuring Quality: Structure, Process, Outcome
Hospital length of stay (in days) is the common measure used to evaluate system utilization.