Bias in published cost effectiveness studies: systematic reviewBMJ 2006; 332 doi: https://doi.org/10.1136/bmj.38737.607558.80 (Published 23 March 2006) Cite this as: BMJ 2006;332:699
- Chaim M Bell, assistant professor of medicine and health, policy, management, and evaluation ()1,
- David R Urbach, assistant professor of medicine and health, policy, management, and evaluation2,
- Joel G Ray, assistant professor of medicine and health, policy, management, and evaluation1,
- Ahmed Bayoumi, assistant professor of medicine and health, policy, management, and evaluation1,
- Allison B Rosen, assistant professor of medicine3,
- Dan Greenberg, senior lecturer4,
- Peter J Neumann, director5
- 1 St Michael's Hospital, Toronto, Ontario, Canada M5B 1W8
- 2 University Health Network, Toronto
- 3 University of Michigan, Ann Arbor, MI, USA
- 4 Health Systems Management, Ben-Gurion University of the Negev, Beersheba, Israel
- 5 Center for the Evaluation of Value and Risk in Health, Institute for Clinical Research and Health Policy Studies, Tufts University School of Medicine, Boston, USA
- Correspondence to: C M Bell, St Michael's Hospital, Toronto, Ontario, Canada M5B 1W8
- Accepted 22 December 2005
Objective To investigate if published studies tend to report favourable cost effectiveness ratios (below $20 000, $50 000, and $100 000 per quality adjusted life year (QALY) gained) and evaluate study characteristics associated with this phenomenon.
Design Systematic review.
Studies reviewed 494 English language studies measuring health effects in QALYs published up to December 2001 identified using Medline, HealthSTAR, CancerLit, Current Content, and EconLit databases.
Main outcome measures Incremental cost effectiveness ratios measured in dollars set to the year of publication.
Results Approximately half the reported incremental cost effectiveness ratios (712 of 1433) were below $20 000/QALY. Studies funded by industry were more likely to report cost effectiveness ratios below $20 000/QALY (adjusted odds ratio 2.1, 95% confidence interval 1.3 to 3.3), $50 000/QALY (3.2, 1.8 to 5.7), and $100 000/QALY (3.3, 1.6 to 6.8). Studies of higher methodological quality (adjusted odds ratio 0.58, 0.37 to 0.91) and those conducted in Europe (0.59, 0.33 to 1.1) and the United States (0.44, 0.26 to 0.76) rather than elsewhere were less likely to report ratios below $20 000/QALY.
Conclusion Most published analyses report favourable incremental cost effectiveness ratios. Studies funded by industry were more likely to report ratios below the three thresholds. Studies of higher methodological quality and those conducted in Europe and the US rather than elsewhere were less likely to report ratios below $20 000/QALY.
Contributors All authors contributed to the conception and design of the project, revised the article critically for important intellectual content, and provided final approval of the final version. CMB, DRU, JGR, and AB analysed and interpreted the data and helped to draft the article. CMB had access to all of the data and takes responsibility for the integrity of the data and the accuracy of the data analysis. CMB and PJN are guarantors.
Funding Agency for Health Care Research and Quality (RO1 HS10919). CMB and JGR are recipients of a phase 2 clinician scientist award and a new investigator award, both from the Canadian Institutes of Health Research. DRU holds a career scientist award from the Ontario Ministry of Health.
Competing interests None declared.