The case-referent study: Are difficulties in its reporting and interpretation affecting non-rct systematic reviews? Would an extension to strobe help?

K. S. MacGilchrist, R. S. Bhopal

Research output: Contribution to journalMeeting abstractpeer-review


The quality of evidence provided by systematic reviews rests on clear reporting in original papers. A STROBE checklist aids reporting of case-control studies, but does not distinguish different case-referent designs. These latter include case-base, incidence density and case-exposure designs, as well as the (traditionally understood) case-control study. The measure estimated and, if an odds ratio, how that may be interpreted, is dependent upon the design. In spite of methodology elaborated over four decades, a 2000 review identified numerous difficulties with authors' reporting and interpretation of case-referent studies, and a review a decade later indicated that such issues prevailed.
To provide guidance on reporting of case-referent studies. METHODS: Medline search in 2000 for odds ratio, relative risk, rare disease assumption and rarity assumption; review of collection of articles from R. Bhopal; snowballing.
1) State the reference series sampling scheme. Cumulative incidence (traditional or exclusive), incidence density (concurrent) or case-base (inclusive), sampling. 2) State whether incident and/or prevalent cases enrolled 3) State what your case-referent study is calculating. A true odds ratio will only result from a case-controlstudy. Incidence density sampling, where the reference series is used to calculate population time, yields an incidence density ratio and case-base sampling enables direct calculation of a risk ratio. 4) State the formal assumptions made or formulae used 5) Refrain from 'labelling' effect measures relative risk (especially in the abstract).
For case-referent studies to be incorporated into systematic reviews authors should report and editors should require greater technical detail. Would an extension of STROBE help?
Original languageEnglish
Pages (from-to)A54-A54
Number of pages1
JournalValue in Health
Issue number3
Publication statusPublished - 1 May 2013

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