Pengukuran penyakit dalam populasi 3/2014 DISIAPKAN OLEH PROF. DR.DRH.PRATIWI, TS. MS DRH.ROSITAWATI, I. MP 2/22/2014PTS-RST-PKH

Ruang Lingkup & Kegiatan Epidemiologi 2/22/20142PTS-RST-PKH

Ilmu yang dibutuhkan Epidemiolog Public health : – Sebab fokus atau penekanan bidang ilmu epidemiologi adalah pencegahan penyakit Medik klinik : – Sebab penekanan epidemiologi adalah pada klasifikasi & diagnosis penyakit Patofisiologi : – Kebutuhan pemahaman yang baik tentang mekanisme biologi suatu penyakit Statistik : – Untuk kuantifikasi frekuensi penyakit dll Sain sosial : – Perlu memahami konteks sosial di wilayah terjadinya penyakit 2/22/20143PTS-RST-PKH

Endemic commonly presents the constant occurrence of a disease that commonly presents in a particular place with stability in the level of infection Endemic pattern 2/22/20144PTS-RST-PKH

Sporadic pattern Sporadic: An irregular occurrence of a disease that commonly presents in a particular place 2/22/20145PTS-RST-PKH

Epidemic the occurrence of a disease that the level of infection exceeds that normal expectancy in a specific region, spreads rapidly and usually lasts for a limited period of time – Pandemic: widespread epidemic that affects a large part of population in many countries – Epizootic: epidemic that involves animal host population 2/22/20146PTS-RST-PKH

Epidemic pattern 2/22/20147PTS-RST-PKH

Epidemic patterns 2/22/20148PTS-RST-PKH

Disease outbreak survey of disease data count of cases describe – person / animal – place – time 2/22/20149PTS-RST-PKH

Environment HostAgent Environment Host Agent Environment Host Agent 2/22/201410PTS-RST-PKH

Environment HostAgent Environment HostAgent 2/22/201411PTS-RST-PKH

Natural history of disease Normal Risk factors Disease Death recover disabled 2/22/201412PTS-RST-PKH

Infection Susceptible Dynamics of infectiousness Dynamics of disease Incubation period Symptomatic period Non-diseased Latent period Infectious period Non-infectious Infection Time (www)www Timeline for Infection 2/22/201413PTS-RST-PKH

Iceberg principle of disease 2/22/201414PTS-RST-PKH

Iceberg (phenomenon) Principle 2/22/201415PTS-RST-PKH

Iceberg phenomenon death disability Clinical Clinical Pre-clinical Susceptibility Healthy 2/22/201416PTS-RST-PKH

Clinical Sub-clinical Outcome Host susceptibility Exposure Agent source Steps in the Disease Process 2/22/201417PTS-RST-PKH

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Type of Epidemiology (Study design) Descriptive epidemiology – survey: time, place, person – Case report, case series Analytical epidemiology (risk factors) – Cross-sectional – Cohort – Case-control Experimental epidemiology – Randomized control trial – Clinical trial – Community trial 2/22/201419PTS-RST-PKH

Measuring disease frequency has several (8) components: Classifying & categorizing disease Deciding what constitutes a case of disease in a study Finding a source for ascertaining the cases Defining the population at risk of disease 2/22/201420PTS-RST-PKH

Measuring disease frequency has several (8) components: Defining the period of time of risk of disease Obtaining permission to study people/animal Making measurement of disease frequency Relating cases to population and time at risk 2/22/201421PTS-RST-PKH

Epidemiology study Distribution Risk factors Analytic study Descriptive study 2/22/201422PTS-RST-PKH

Descriptive epidemiology Epidemiology Distribution Risk factors Time Place Person Analytic study Descriptive study Etiology 2/22/201423PTS-RST-PKH

Descriptive epidemiology What (How much): occurred Who: animals or humans When: time Where: place 2/22/201424PTS-RST-PKH

Descriptive epidemiology Detection of individual case Detection of outbreaks Measuring the impact of disease Understand the nature of a disease Understand the way that disease spreads and is distributed 2/22/201425PTS-RST-PKH

Descriptive epidemiology Generate hypotheses and ideas for further research Evaluation of prevention and control measures Support planning activities for animal health program 2/22/201426PTS-RST-PKH

Basic Measures and Tools of Descriptive Epidemiology Data collection classification / organization summarizing presentation 2/22/201427PTS-RST-PKH

Incidence rate Incidence No. of new cases of a disease occurring in the population during a specified period of time No. of persons who are at risk of developing the disease during that period of time x100 the number of NEW cases that develop over a certain time period. 2/22/201428PTS-RST-PKH

No. of cases of a disease present in the population at a specified time No. of persons in the population at that specified time Prevalence rate x100 the number of existing cases including old and new cases that have developed at some point during a time period. Prevalence 2/22/201429PTS-RST-PKH

Incidence and Prevalence 2/22/201430PTS-RST-PKH

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Example QuestionType of measure Do you currently have asthma?Point prevalence Have you had asthma during the last 2 years?Period prevalence Have you ever had asthma?Cumulative incidence 2/22/201432PTS-RST-PKH

No of deaths Population Mortality rate = No of deaths No of clinically ill Case fatality rate = 2/22/201433PTS-RST-PKH No of clinically ill Population Morbidity rate = No of infected Population Infection rate =

Analytical epidemiology How: adjust policy and response Why: prevent and control 2/22/201434PTS-RST-PKH

Cross-sectional A random sample of individuals from a population is taken at a point in time Surveys to collect data 2/22/201435PTS-RST-PKH

Cross-sectional Advantages: – quick to conduct and cost is moderate compared with other study designs. Disadvantages: – cannot provide information on the incidence of disease in a population only an estimate of prevalence – Difficult to investigate cause and effect relationships 2/22/201436PTS-RST-PKH

Cohort Comparing disease incidence over time between groups Prospective cohort – Non-disease case – Expose and non-expose Retrospective cohort – Disease case – Evaluated for evidence of exposure to the agent 2/22/201437PTS-RST-PKH

Cohort 2/22/201438PTS-RST-PKH

Cohort Advantages: – monitored over time for disease occurrence – estimates of the absolute incidence of disease in exposed and non-exposed Disadvantages: – long follow-up period – case of rare diseases large groups are necessary – Losses to follow-up – expensive 2/22/201439PTS-RST-PKH

Case-control Comparing the frequency of past exposure between cases who develop the disease (or other outcome of interest) and controls chosen to reflect the frequency of exposure in the underlying population at risk 2/22/201440PTS-RST-PKH

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Case-control Advantages: – an efficient method for studying rare diseases – subjects have experienced the outcome of interest at the start of the study – quick to run and cheaper than other study Disadvantages: – Can not provide information on the disease incidence in a population – Reliant on the quality of past records or recollection of study participants – Difficult to ensure an unbiased selection of the control group 2/22/201442PTS-RST-PKH

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Bingung hiks 2/22/201444PTS-RST-PKH

Sampai minggu ke 4 2/22/2014PTS-RST-PKH