A study of series of clinical cases (or situations of any type that are related to scientific, industrial, academic research, etc.) is an epidemiological, descriptive study, which is limited to the simple identification and description of a set of clinical cases that have appeared in an interval of time.
In the case of new diseases or drugs, the series of cases contribute to the characterization of the profile and delimitation of new nosological entities. However, in order to assess the importance of the antecedents and possible associations, the presence of a control group that serves as and comparison is necessary.
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