Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/8854
Appears in Collections:Faculty of Health Sciences and Sport Journal Articles
Peer Review Status: Refereed
Title: Drug exposure risk windows and unexposed comparator groups for cohort studies in pharmacoepidemiology
Authors: McMahon, Alex
Evans, Josie
McGilchrist, Mark M
McDevitt, Denis G
MacDonald, Thomas M
Contact Email: josie.evans@stir.ac.uk
Keywords: Cohort study
Risk window
Unexposed group
Pharmacoepidemiology
MEMO
Issue Date: Aug-1998
Publisher: John Wiley and Sons for the International Society for Pharmacoepidemiology
Citation: McMahon A, Evans J, McGilchrist MM, McDevitt DG & MacDonald TM (1998) Drug exposure risk windows and unexposed comparator groups for cohort studies in pharmacoepidemiology, Pharmacoepidemiology and Drug Safety, 7 (4), pp. 275-280.
Abstract: Aim: To determine the appropriate size of risk windows in both exposed and unexposed sub-cohorts. Method: Data was taken from a previous study of upper gastrointestinal haemorrhage and perforation. The length of each prescription for NSAIDs was estimated. The risk was calculated for the duration of a prescription plus increments of -30, -25, ..., +115, +120 (i.e. 31 increments). Ten unexposed groups were re-sampled for each increment (stratified for age and sex), using the same lengths of risk window as the exposed group. Mean risks and rate-ratios were calculated (per thousand person-years). Results: The NSAID risk rose from 3·52 at -30 days to a peak of 5·82 at -15 days, and then decreased gradually to 2·83 at +120 days. Unexposed risk was variable for the negative increments, and decreased gradually from 2·16 at +0 days to 1·54 at +120 days. The rate-ratio rose from 1·55 at -30 days to a peak of 2·85 at -5 days, and then decreased to 1·85 at +120 days. Conclusion: Risk windows should be the same as (or slightly less than) the calculated length of a prescription. Lengthy windows should not be used for unexposed comparator groups (the exposed windows may be randomly allocated).
Type: Journal Article
URI: http://hdl.handle.net/1893/8854
URL: http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-1557(199807/08)7:4%3C275::AID-PDS363%3E3.0.CO;2-N/abstract
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: ASS Management and Support Team
HS Research - Stirling
Ninewells Hospital & Medical School
Ninewells Hospital & Medical School
Ninewells Hospital & Medical School

Files in This Item:
File Description SizeFormat 
Evans_1998_Drug_Exposure_Risk.pdf103 kBAdobe PDFUnder Embargo until 31/12/2999     Request a copy

Note: If any of the files in this item are currently embargoed, you can request a copy directly from the author by clicking the padlock icon above. However, this facility is dependant on the depositor still being contactable at their original email address.

This item is protected by original copyright



Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

If you believe that any material held in STORRE infringes copyright, please contact library@stir.ac.uk providing details and we will remove the Work from public display in STORRE and investigate your claim.