FREQUENCY IN EPIDEMIOLOGY

FREQUENCY IN EPIDEMIOLOGYFAJAR AWALIA YULIANTO1LAST SESSIONDOES ANYBODY STILL REMEMBER THE DEFINITION OF EPIDEMIOLOGY?DISTRIBUTIONDETERMINANTPOPULATIONdistributionMEASURE THE FREQUENCY IN A DISEASETHE PARAMETER OF THE FREQUENCY ARE:COUNTSRATIOPROPORTIONRATECOUNTSTHE SIMPLEST MEASURE IN EPIDEMIOLOGYREFERS TO THE NUMBERS OF CASES OF A DISEASE OR OTHER HEALTH PHENOMENON BEING STUIDIEDe. g. NUMBER OF PERSONS WHICH BEEN NEWLY DIAGNOSED HAVING TUBERCULOSIS IS 245 THIS MONTHUSEFUL FOR ALLOCATION OF HEALTH RESOURCESLIMITED USEFULLNESS FOR EPIDEMIOLOGIC PURPOSES WITHOUT KNOWING SIZE OF THE SOURCE POPULATIONRATIOTHE QUOTIENT OF 2 NUMBERS (NUMERATOR AND DENOMINATOR)A QUANTITY DIVIDE THE QUANTITYNUMERATOR MIGHT BE DIFFERENCE FROM THE DENOMINATOR (NUMERATOR MIGHT NOT INCLUDED IN DENOMINATOR)e. g. SEX RATIO= PROPORTION OF MALES/PROPORTION OF FEMALESACREDITATION=STUDENT/TEACHERPROPORTIONTYPE OF RATIO, WITH THE NUMERATOR AS PART OF DENOMINATOR (NECESSARY!)USUALLY MULTIPLIED BY 100, KNOWN AS PERCENTAGEPROPORTION ALWAYS RANGES BETWEEN 0 AND 1e. g. 16 CASES OF DISEASE FROM 48 PEOPLE. THE PROPORTION OF THE CASE IS 30%RATETYPE OF RATIO THAT QUANTIFIES DYNAMIC PROCESS I. E. GROWTH AND ACCELERATIONFREQUENCY OF AN EVENTRATE CONTAIN:DISEASE FREQUENCYUNIT SIZE IN POPULATIONTIME PERIOD DURING WHICH AN EVENT OCCURSRATE = (NUMERATOR/DENOMINATOR)X FNUMERATOR: SUM OF INDIVIDUAL EXPERIENCED IN AN EVENTDENOMINATOR: SUM OF POPULATION AT RISKF: CONSTANTArememberIN EPIDEMIOLOGY, WE HAVE TO DEFINE THE:DISEASEPOPULATIONTIMEFRAME

DISEASEABNORMAL AMONG THE NORMALSDIAGNOSED FROM:SYMPTOMSSIGNSMEDICAL HISTORYTEST RESULTPOPULATIONGROUP OF PEOPLE WITH THE SAME PURPOSES, LIMITED BY TIME AND PLACEPOPULATION AT RISK IS THE MAIN DENOMINATOR FOR DISEASE FREQUENCY IN EPIDEMIOLOGY (NOT THE POPULATION!)CLASSIFICATION:CLOSED POPULATION: SUBJECT ENTER AT THE SAME TIME AND THERE ARE VERY FEW LOSSES TO FOLLOW UPOPEN POPULATION: SUBJECTS ENTER AT ANY TIME AND THERE ARE MANY LOSSES TO FOLLOW UP

TIMEFRAMEPOINT (SNAPSHOT)

PERIOD (FOLLOWED)

BASIC MEASURE OF DISEASE FREQUENCYPOINT PREVALENCEPERIOD PREVALENCEINCIDENCE PROPORTIONINCIDENCE RATEPOINT PREVALENCEPROPORTION OF THE POPULATION AT RISK WHO HAVE THE DISEASE AT A PARTICULAR MOMENT (SNAPSHOT)PERIOD PREVALENCEPROPORTION OF THE POPULATION AT RISK WHO HAVE THE DISEASE WITHIN A CERTAIN PERIOD (VIDEOCAMERA)POPULATION AT RISK IN PERIOD PREVALENCE IS (PARstart+PARend)/2JADI APA ARTINYA (GUNANYA) PREVALENSI?Prevalens

Merefleksikan jumlah kasus yang ada (kasus lama maupun kasus baru) dalam populasi dalam suatu waktu atau periode waktu tertentu

probabilitas bahwa seorang individu menjadi kasus (atau menjadi sakit) dalam waktu atau periode waktu tertentu

INCIDENCE PROPORTION (CUMULATIVE INCIDENT)REFLECTS THE ABSOLUTE RISK FOR DISEASE WITHIN A GIVEN POPULATIONIP= N NEW CASES/N DISEASE FREE AT THE START OF FOLLOW UPPEOPLE WHO HAVE THE DISEASE IS NOT INCLUDED IN DENOMINATOR07/10/2014Ukuran-ukuran frekuensi yang digunakan dalam epidemiologi17 Cumulative Incidence Incidence proportionRiskCI assumes that entire population at risk followed up for specified time periodxxxxxxxx disease onsetMonth 1Month12CI = 7/12 per year = 0.58 per year17INCIDENCE RATE (INCIDENSE DENSITY,HAZARD RATE, PERSON TIME RATE, DISEASE INTENSITYTHE INCIDENCE RATE MEASURES THE PACE AT WHICH NEW CASE OCCUR IN A POPULATIONIR=N NEW CASES/SUM OF DISEASE-FREE TIME OF EACH INDIVIDUALEACH PERSON OBSERVED UNTIL DIAGNOSIS OF DISEASE, END OF STUDY, LOSS TO FOLLOW UP10/7/2014Ukuran-ukuran frekuensi yang digunakan dalam epidemiologi19Ukuran-ukuran frekuensi penyakitLatihan menghitung Incindence Rate

0255075100TahunDDD = permulaan sakitPopulasi 2Hitung Incidence Rate pada populasi 2=2/(75+100)=2/175 person years=0.0114 = 11.4 per 1000 person-years BAGAIMANA BILA OBSERVASI YANG DILAKUKAN PADA JUMLAH POPULASI YANG BESAR?Example of a rate in an open population

In one year, we observe 2,391,630 deaths. The average population size is 272,705,815. The death rate is:Jadi apa artinya (gunanya) insidensi?Insidens

Merupakan alat ukur untuk penelitian etiologi suatu penyakit baik akut maupun kronis

Merupakan indikator yang baik untuk mengestimasi suatu resiko oleh karena insidens mengukur secara langsung peluang bahwa seseorang yang sehat akan menjadi sakit

Insidens rate yang tinggi dari suatu penyakit menunjukkan resiko yang tinggi untuk mendapatkan penyakit tersebut

Insidens memberikan informasi mengenai efektifitas dari suatu pencegahan atau intervensi terhadap suatu penyakit10/7/2014Ukuran-ukuran frekuensi yang digunakan dalam epidemiologi23

10/7/2014Ukuran-ukuran frekuensi yang digunakan dalam epidemiologi24

Ukuran-ukuran frekuensi penyakitPerbandingan Insidens dan PrevalensInsidensPrevalens Hanya menghitung kasus baru

Tingkat tidak bergantung durasi rata-rata penyakit Dapat diukur sebagai rate atau proporsi Merefleksikan kemungkinan menjadi penyakit sepanjang waktu Lebih disukai bila melakukan studi etiologi penyakit Menghitung kasus yang ada (kasus baru dan lama) Bergantung pada rata-rata lama (durasi) sakit Selalu diukur sebagai proporsi

Merefleksikan kemungkinan terjadi penyakit pada satu waktu tertentu Lebih disukai bila studi utilisasi pelayanan kesehatan

HOMEWORK ASSIGNMENT (FREQUENCY EPIDEMIOLOGY)PLEASE LOG IN TO:http://vimeo.com/46161438 AND MAKE YOUR SUMMARY OF THER ANIMATIONTRUE OR FALSE. EXPLAIN THE ANSWERWE CAN MEASURE THE INCIDENCE IN HOSTPITAL (T/F)PREVALENCE IS THE EXAMPLE OF RATIO (T/F) INCIDENCE IS THE EXAMPLE OF RATE (T/F) Dikumpulkan lewat email ke awaliayulianto@gmail.com paling lambat 3 hari dari sekarang

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