Evidence-Based Medicine & Statistics

Case–Control Study

TROlgu–Kontrol Çalışması
Also known as:Case-referent study

An observational study that starts from people with a given outcome (cases) and comparable people without it (controls) and compares their past exposure to a suspected cause, such as a drug.

In depth

Because sampling is based on outcome, incidence cannot be calculated directly, and the association is expressed as an odds ratio, which approximates the relative risk when the outcome is rare. The design is efficient for rare outcomes, such as serious idiosyncratic adverse drug reactions, and for outcomes with long latency.

Main weaknesses are selection bias in choosing controls, recall bias and confounding. Classic pharmacoepidemiological examples linked in utero diethylstilbestrol exposure to vaginal clear-cell adenocarcinoma, and aspirin use in children to Reye's syndrome. In nested case–control studies, cases and controls are drawn from a defined cohort.

Clinical pearl

Case–control studies are the usual way to test signals of rare reactions such as Stevens–Johnson syndrome or agranulocytosis, which are too infrequent to quantify in clinical trials.

Example drugs

Diethylstilbestrol Acetylsalicylic acid
TRIn Turkish

Olgu–Kontrol Çalışması

Belirli bir sonlanıma sahip kişilerden (olgular) ve bu sonlanıma sahip olmayan benzer kişilerden (kontroller) yola çıkarak, şüphelenilen bir nedene (örneğin bir ilaca) geçmişteki maruziyetlerini karşılaştıran gözlemsel çalışmadır.

Örnekleme sonlanıma göre yapıldığından insidans doğrudan hesaplanamaz; ilişki, sonlanım nadir olduğunda göreceli riske yaklaşan odds oranıyla ifade edilir. Tasarım, ciddi idiyosenkratik advers ilaç reaksiyonları gibi nadir sonlanımlar ve uzun latent dönemli sonlanımlar için verimlidir.

Başlıca zayıflıkları kontrol seçimindeki seçim yanlılığı, hatırlama yanlılığı ve karıştırıcı etkenlerdir. İntrauterin dönemde dietilstilbestrole maruziyet ile vajinal berrak hücreli adenokarsinom ve çocuklarda aspirin kullanımı ile Reye sendromu arasındaki ilişkiler klasik farmakoepidemiyolojik örneklerdir. İç içe (nested) olgu–kontrol çalışmalarında olgular ve kontroller tanımlı bir kohorttan seçilir.

Stevens–Johnson sendromu veya agranülositoz gibi klinik çalışmalarda ölçülemeyecek kadar nadir reaksiyonlara ilişkin sinyaller genellikle olgu–kontrol çalışmalarıyla test edilir.

Diğer adları:Vaka-kontrol çalışması · Olgu-kontrol araştırması
Updated 24.09.2026 0 views Educational reference — verify against current sources before clinical use.

Read next

Cohort StudyKohort Çalışması

An observational study that follows groups of people defined by their exposure (e.g., to a drug) over time and compares the incidence of outcomes between exposed and unexposed groups.

 Odds RatioOdds Oranı

The ratio of the odds of an outcome (or exposure) in one group to the odds in another group, where the odds is the probability that an event occurs divided by the probability that it does not.

 Adverse Drug ReactionAdvers İlaç Reaksiyonu

A noxious and unintended response to a medicinal product in which a causal relationship with the drug is at least a reasonable possibility.

 PharmacovigilanceFarmakovijilans

The science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other medicine-related problem (WHO definition).

 Relative RiskGöreceli Risk

The ratio of the risk (cumulative incidence) of an outcome in an exposed or treated group to the risk in an unexposed or control group over the same period.