Effect of 1995 pill scare on rates of venous thromboembolism among women taking combined oral contraceptives: analysis of General Practice Research Database
BMJ 2000; 321 doi: https://doi.org/10.1136/bmj.321.7259.477 (Published 19 August 2000) Cite this as: BMJ 2000;321:477
- R D T Farmer, professor (r.farmer{at}surrey.ac.uk),
- T J Williams, research fellow,
- E L Simpson, research officer,
- A L Nightingale, research officer
- Pharmacoepidemiology and Public Health, Postgraduate Medical School, University of Surrey, Guildford, Surrey GU2 7DJ
- Correspondence to: R D T Farmer
- Accepted 12 July 2000
Abstract
Objective: To compare the incidence of venous thromboembolism among women taking combined oral contraceptives before and after the October 1995 pill scare.
Design: Analysis of General Practice Research Database.
Setting: United Kingdom, January 1993 to December 1998.
Subjects: Women aged 15–49 taking combined oral contraceptives.
Main outcome measures: Incidence of venous thromboembolism.
Results: Use of so called “third generation” combined oral contraceptives fell from 53% during January 1993 to October 1995 to 14% during November 1995 to December 1998. There was no significant change in the incidence of venous thromboembolism between the two periods after age was adjusted for (incidence ratio 1.04, 95% confidence interval 0.78 to 1.39).
Conclusions: The findings are not compatible with the assertion that third generation oral contraceptives are associated with a twofold increase in risk of venous thromboembolism compared with older progestogens.
Footnotes
-
Funding The department is supported by grants from several pharmaceutical companies including NV Organon, Schering AG, and Wyeth. The companies have no control over the conduct of any research or over publications.
-
Competing interests RDTF has been reimbursed expenses for attending conferences by pharmaceutical companies; he has also been paid fees for speaking and consultancy.
- Accepted 12 July 2000