DISAIN STUDI EPIDEMIOLOGI

Maxs U.E. SanamFKH UndanaDISAIN STUDI EPIDEMIOLOGIMETODE PENELITIAN EPIDEMIOLOGISSURVEI vs EKSPERIMENSURVEI : Survei deskriptif vs Survei analitikSURVEI (Noneksperimen)TIDAK ada intervensi/perlakuan terhadap variabelHanya dilakukan observasi terhadap fenomena alam, sosial, atauMencari hubungan fenomena tsb di antara variabelPengambilan data menggunakan sampel dan kuisioner

Deskriptif vs AnalitisSurvei deskriptif (Epidemiologi deskriptif)Dilakukan tanpa hipotesisBiasanya studi awal ataupun studi karakterisasi suatu penyakit baru

Survei analitis (Epidemiologi analitis)Mengidentifikasi dan menguji hipotesis tentang adanya asosiasi antara paparan terhadap faktor risiko dan terjadinya suatu kejadian penyakit (exposure of interest vs a particular outcome)

EKSPERIMENTALAda intervensi/perlakuan terhadap variabelAdanya kelompok KontrolRandomized clinical trial (Uji Klinis Teracak)Community or herd trial (Uji Kelompok atau Masyarakat)

Diagram Pohon menguraikan hubungan di antara tipe-tipe Rancangan Studi Epidemiologis utama

Faktor RisikoFaktor Risiko Intrinsik (berasal dari host)Jenis kelamin dan usiaFaktor anatomi dan fisiologisFaktor nutrisiFaktor imunitasFaktor ekstrinsik (di luar host)Fisik, kimiawi, biologis, psikologis, budaya, perilaku, manajemen

Hubungan antara Agen, Faktor Risiko, dan Efek (Penyakit)Faktor RisikoInternalEksternalAgen penyakitMan/Animals as HostSakitCase Reportsdescribes some newsworthy clinical occurrence, such as unusual combination of clinical signsexperience with a novel treatment, or a sequence of events that may suggest previously unsuspected causal relationships.Case reports are generally reported as a clinical narrative.

Contoh Studi KasusTrivier at al (2001) reported the occurrence of fatal aplastic anaemia in an 88 year-old man who had taken clopidogrel, a relatively new drug on the market that inhibits platelet aggregation. The authors speculated that his fatal illness may have been caused by clopidogrel and wished to alert other clinicians to a possible adverse effect of the drug.Reference: Trivier JM, Caron J, Mahieu M, Cambier N, Rose C (2001). Fatal aplastic anaemia associatedwith clopidogrel. Lancet, 357: 446.Cases seriesA case report shows that something can happen once, a case series shows that it can happen repeatedly. A case series identifies common features among multiple casesand describes patterns of variability among them.Contoh Case SeriesAfter bovine spongiform encephalopathy (BSE) appeared in British cattle in 1987, there was concern that the disease might spread to humans. A special surveillance unit was set up to study Creutzfeld-Jacob disease (CJD), a rare and fatal progressive dementia that shares clinical and pathological features of BSE.In 1996 investigators at the unit described ten cases that met the criteria for CJD but had all occurred at unusually young ages, showed distinctive symptoms and, on pathological examination, had extensive prion protein plaques throughout the brain similar to BSE.

Reference: Will RG, Ironside JW, Zeidler M, Cousens SN, Estibeiro K, Alperovitch A et al (1996). A new variant of Creutzfeld-Jacob disease in the UK. Lancet, 347: 921 - 925.Descriptive studies based on ratesDescriptive studies based on rates quantify the burden of disease on a population Using incidence, prevalence, mortality or other measures of disease frequency. Most use data from existing sources (such as birth and death certificates, disease registries or surveillance systems). Descriptive studies can be a rich source of hypotheses that lead later to analytic studies.Contoh Studi deskriptis yang didasarkan pada frekuensi/intensitasSchwarz et al (1994) conducted a descriptive epidemiological study of injuries in a predominantly African-American part of Philadelphia. An injury surveillance system was set up in a hospital emergency centre.Denominator information came from US census data. These authors found a high incidence of intentional interpersonal injury in this area of the city.

Reference: Schwarz DF, Grisso JA, Miles CG, Holmes JH, Wishner AR, Sutton RL (1994). A longitudinal study of injury morbidity in an African-American population. Journal of the American Medical Association,271: 755 - 760.