Check the journal's requirements (e.g. the number of words). Sometimes such short articles are published to respond to some recent articles (e.g. to argue that something Prof. X found in country/region/patient group/firm/... Y is not true in country/... Z) or that the author(s) of the previous study made a mistake in definitions, methods, selection of reviewed articles (e.g. ignoring some important keywords).... In such studies authors do not usually cite so many papers (they will maybe cite 10-20) and they mainly focus on the article they comment.