Sandra Nordmann, Lucie Biard, Philippe Ravaud, Marina Esposito-Farèse, Florence Tubach

Case-only designs have been used since late 1980's. In these, as opposed to case-control or cohort studies for instance, only cases are required and are self-controlled, eliminating selection biases and confounding related to control subjects, and time-invariant characteristics. The objectives of this systematic review were to analyze how the two main case-only designs - case-crossover (CC) and self-controlled case series (SCCS) - have been applied and reported in pharmacoepidemiology literature, in terms of applicability assumptions and specificities of these designs.