UKURAN DAMPAK DALAM EPIDEMIOLOGI€¦ · Ukuran-ukuran dampak • Population Attributable Risk...

UKURAN DAMPAK DALAM EPIDEMIOLOGI

Putri Handayani, M.KKK

Measures of Public Health Impact

• Attributable Risk (AR) Number

• Attributable Risk Percent (AR%) Percentage

• Population Attributable Risk (PAR) Number

• Population Attributable Risk Percent

(PAR%) Percentage

Measures of Public Health Impact

IMPORTANT!

They all assume (require) that a cause-effectrelationship exists between the exposure and the outcome.

Relative Risk vs. Attributable Risk

Relative Risk: Measure of the strength of association, and indicator used to assess the possibility of a causal relationship.

Attributable Risk: Measure of the potential for prevention of disease if the exposure could be eliminated (assuming a causal relationship).

Relative Risk vs. Attributable Risk

Relative Risk:

• Etiology

Attributable Risk:

• Policy decisions

• Funding decisions (e.g. prevention programs)

Tipe ukuran yang digunakan dalam epidemiologi

• Ukuran efek/dampak

– Merefleksikan dampak suatu faktor pada frekuensi atau risiko dari suatu masalah (outcome) kesehatan

– Merefleksikan kelebihan jumlah kasus karena suatu faktor (attributable) atau jumlah kasus yang dapat dicegah oleh eksposur (pemajan)

Ukuran-ukuran dampak

• Ukuran perbedaan dampak/efek

– Perbedaan risiko = Risk Difference (RD) = Attributable Risk (AR) = Excess Risk (ER) = Absolute Risk (AR)

• [Risiko pada kelompok terpajan] – [Risiko pada kelompok tidak terpajan]

• Berguna untuk mengukur besarnya masalah kesehatan masyarakat yang disebabkan oleh suatu pemajan

• bermanfaat untuk penilaian prioritas untuk aksi kesehatan masyarakat (Public Health Action)

Attributable Risk (AR)

Among the EXPOSED:

How much of the disease that occurs can be attributed to a certain exposure?

AR

AR%

This is of primary interest to the practicing clinician.

Attributable Risk (AR)

AR = Iexposed – Inonexposed = “Risk Difference”

Smoke Yes No

Yes 84 2916 3000

No 87 4913 5000

Develop CHD ISM = 84 / 3000

= 0.028 = 28.0 / 1000

INS = 87 / 5000

= 0.0174 = 17.4 / 1000

(background risk)

AR = (28.0 – 17.4) / 1000 = 10.6 / 1000

Attributable Risk (AR)

AR = (28.0 – 17.4) / 1000 = 10.6 / 1000

Among SMOKERS, 10.6 of the 28/1000 incident cases of CHD are attributed to the fact that these people smoke …

Among SMOKERS, 10.6 of the 28/1000 incident cases of CHD that occur could be prevented if smoking were eliminated.

Ukuran-ukuran dampak

• Ukuran perbedaan dampak/efek

– Perbedaan insidens kumulatif = Cumulative Incidence Difference= CID

[IK pada kelompok terpajan] - [IK pada kelompok tidak terpajan]

IK = Insidens Kumulatif

Ukuran-ukuran dampak

• Ukuran perbedaan efek

– Perbedaan rate/ perbedaan densitas insidens (IDD = Insidence Density Difference)

• IDD =

[Densitas insidens dalam kelompok terpajan] - [Densitasinsidens pada kelompok tidak terpajan]

Ukuran-ukuran dampak

• Ukuran perbedaan efek

– Perbedaan prevalens (PD = Prevalence Differrence)

PD = [Prevalens dalam kelompok terpajan] - [Prevalens dalam kelompok tidak terpajan]

Attributable Risk

Incidence

Exposed Unexposed

Iexposed - Iunexposed

Ukuran-ukuran dampak/efek

• Ukuran perbedaan efek

– Attributable Risk (AR) Percent = AR%

%100Insidens

InsidensInsidensAR%

terpajan

terpajantidakterpajanx

Attributable Risk Percent (AR%)

AR% = (Iexposed – Inonexposed) / Iexposed = “Etiologic fraction”

Smoke Yes No

Yes 84 2916 3000

No 87 4913 5000

Develop CHD

AR% = (28.0 – 17.4) / 28.0 = 37.9%

ISM = 84 / 3000

= 0.028 = 28.0 / 1000

INS = 87 / 5000

= 0.0174 = 17.4 / 1000

(background risk)

Attributable Risk Percent (AR%)

AR% = (28.0 – 17.4) / 28.0 = 37.9%

Among SMOKERS, 38% of the morbidity from CHD may be attributed to smoking…

Among SMOKERS, 38% of the morbidity from CHD could be prevented if smoking were eliminated.

Attributable Risk Percent

Incidence

Exposed Unexposed

Iexposed – Iunexposed RR - 1

------------------------------- = ------------ x 100%

Iexposed RR

Ukuran-ukuran dampak

• Population Attributable Risk (PAR)

– = Attributable Fraction (population) atau Etiologic Fraction (population) = Population Attributable Risk Proportion = Population Attributable Risk Fraction

– Proporsi (atau fraksi) rate penyakit pada seluruh populasi yang mewakili rate penyakit dalam kelompok terpajan

– Rumus PAR

terpajantidakpopulasi InsidensInsidensPAR

Ukuran-ukuran dampak

• Population Attributable Risk Percent (PARP)attributable fraction (population) atau etiologic fraction (population)– Berarti proporsi kasus baru yang dapat dicegah jika pada semua

orang yang tidak terpajan

– Rumus PAR%

%100Insidens

InsidensInsidensPAR%

populasi

terpajantidakpopulasix

Population Attributable Risk Percent

PAR% = (Itotal – Inonexposed) / Itotal

Weight Yes No

Obese 850 3650 4500

Slim 250 5250 5500

Diabetes

PAR% = (110 – 45.5) / 110 = 58.6%

1100 8900 10000

IT = 1100 / 10000

= 0.11 = 110 / 1000

INE = 250 / 5500

= 0.0455 = 45.5 / 1000

(background risk)

Population Attributable Risk Percent

PAR% = (110 – 45.5) / 110 = 58.6%

In Tampa, 59% of the cases of diabetes may be attributed to obesity in the population…

In Tampa, 59% of the cases of diabetes could be prevented if Tampa residents lost sufficient weight.

Prevented Fraction (PF)

• If relative risk <1

– Proportion of potential new cases which would have occurred if the exposure had been absent

– Proportion of potential cases prevented by the exposure

RR -1

I

I -I PF

unexposed

exposed unexposed

PF: Vaccine efficacy

Pop. Cases Cases/1000 RR

Vaccinated 301,545 150 0.49 0.28

Unvaccinated 298,655 515 1.72 Ref.

Total 600,200 665 1.11

0.72 0.28 - 1

0.72 1.72

0.49 - 1.72 PF

Ringkasan ukuran

Tipe

Kuantitas

Matematis

Tanpa

denominator

Dengan

denominator

Enumerasi

Hitung,

angka mutlakRasio Proporsi Rate

Ringkasan ukuran

Tipe

Kuantitas

Matematis

Enumerasi Rasio Proporsi Rate

•RR

•OR

•IDR

•%

•AR%

•PAR%

•Crude

•Spesific

•Adjusted

Ringkasan ukuran

Ukuran

dalam

epidemiologi

Ukuran

Frekuensi

Penyakit

Ukuran

asosiasi

Ukuran efek

/dampak

Ukuran frekuensi penyakit

Ukuran

frekuensi

Penyakit

Insidens Prevalens

Insidens

Kumulatif

Incidence

Density

Prevalens

titik

Prevalens

periode

Mortalitas

Ukuran frekuensi penyakit

Ukuran

Rasio

Risk

Ratio

Odds

Rasio

Insidence

Density

Ratio

Prevalence

Ratio

Ukuran frekuensi penyakit

Ukuran

Efek

/dampak

Perbedaan

efek

Fraksi

Efek

RD

AR

ER

PAR

AR% PAR% PF

RD = Risk Difference

AR = Attributable Risk

ER = Excess Risk

PAR = Population Attributable Risk

PF = Prevented Fraction