[The choice of the type of design in the clinical investigation studies. Case and control studies].
Case-control studies are appropriate designs in neurology sciences to search for risk factors that have already occurred in a group of patients. In them, the subjects are selected on the basis of whether they have the disease or not and then they are compared in regards to the risk factor or prognosis investigated. These sorts of designs can be performed in a shorter and cheaper way than the regular cohort studies. They are appropriate for the evaluation of rare diseases and can examine multiple etiological factors for a single disease. On the contrary, they are not so efficient when rare exposures are involved. Incidence rates in exposed and non-exposed subjects cannot be calculated and on some occasions, the timing between exposure and outcome can be very difficult to establish. The Odds Ratio and its confident intervals is the measurement used for estimating the risk strength in this design. The clinical neurologist should be familiar with these terms, given the frequency of case-control studies described in neurology science literature, and should know their principal advantages and limitations.
Posada de la Paz
M
M
Centro de Investigaciones sobre el Síndrome del Aceite Tóxico, Subdirección General de Epidemiología y Centros Nacionales de Salud Pública, Instituto de Salud Carlos III, Madrid. mposada@isciii.es
D016022:Case-Control Studies; D006801:Humans; D009462:Neurology / Q000379:methods; D012107:Research Design; D012307:Risk Factors
La elección del tipo de diseño en los estudios de investigación clínica. Estudios de casos y controles.