Article Text
PostScript
Letter
Case–control or cohort study?
Statistics from Altmetric.com
In a recently published article by Chandra et al the authors have stated that they conducted a ‘case-controlled’ study to examine the anticoagulant effect of warfarin in vitreoretinal surgery.1 However, this study was conducted on a cohort of patients receiving pars plana vitrectomy (PPV); 60 patients who received warfarin (exposure) on the day of …
Footnotes
Competing interests None.
Provenance and peer review Not commissioned; not externally peer reviewed.
Request Permissions
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Copyright information:
© 2011, Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.