Meta-analysis when only the median survival times are known: A comparison with individual patient data results.
Abstract
BACKGROUND: The hazard ratio (HR) is the most appropriate measure for time to event outcomes such as survival. In systematic reviews, HRs can be calculated either from the raw trial data obtained as part of an individual patient data (IPD) meta-analysis or from the appropriate trial-level summary statistics. However, the information required for the latter are seldom reported in sufficient detail to allow reviewers to calculate HRs. In contrast, the median survival and survival rates at specific time points are frequently presented. We aimed to evaluate retrospectively the performance of meta-analyses using median survival times and survival rates by comparing them with meta-analyses using IPD to calculate HRs. METHODS: IPD from thirteen published meta-analyses (MAs) in cancers with high mortality rates were used. Median survival and survival rates were calculated from the IPD rather than taken from publications so that the same trials, patients, and extended follow-up are used in each analysis. RESULTS AND CONCLUSIONS: We show that using median survival times or survival rates at a particular point in time are not reasonable surrogate measures for meta-analyses of survival outcomes and that, wherever possible, HRs should be calculated. Individual trial publications reporting on time to event outcomes, therefore, should provide more detailed statistical information, preferably logHRs and their variances, or their estimators.
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Risk ratio and odds ratio (in relation to events occurring by a fixed time) are not equivalent to the hazard ratio.
“Risk ratio and odds ratio (in relation to events occurring by a fixed time) are not equivalent to the hazard ratio, and median survival times are not a reliable basis for meta-analysis [112].”
From The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration (2009) · cites this paper as [112]
Median survival times are not a reliable basis for meta-analysis.
“median survival times are not a reliable basis for meta-analysis [112].”
From The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration (2009) · cites this paper as [112]
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“Risk ratio and odds ratio (in relation to events occurring by a fixed time) are not equivalent to the hazard ratio, and median survival times are not a reliable basis for meta-analysis (112).”
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Liberati, A., Altman, D. G., Tetzlaff, J., Mulrow, C., Gøtzsche, P. C., Ioannidis, J. P. A., Clarke, M., Devereaux, P. J., Kleijnen, J., & Moher, D. (2009) · Italian Journal of Public Health · doi:10.2427/5768 · Cited by 3,374 · see citing works
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- Authors
- Michiels, S., Piedbois, P., Burdett, S., Syz, N., Stewart, L., & Pignon, J.-P.
- Affiliations
- Institut Gustave Roussy (FR)
- Centre Hospitalier Universitaire Henri-Mondor (FR)
- MRC Clinical Trials Unit at UCL (GB)
- Venue
- International Journal of Technology Assessment in Health Care
- Publisher
- Cambridge University Press (CUP)
- Published
- 2005-01
- Volume
- 21
- Issue
- 1
- Pages
- 119-125
- ISSN
- 0266-4623 (ISSN-L)
- 1471-6348
- OpenAlex
- W2147082943
- Cited by
- 154
- References
- 32
- Citations by year
- 2026: 2 · 2025: 3 · 2024: 5 · 2023: 4 · 2022: 3 · 2021: 18 · 2020: 18 · 2019: 3 · 2018: 2 · 2017: 8 · 2016: 18 · 2015: 10 · 2014: 10 · 2013: 12 · 2012: 10
- FWCI
- 3.47
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- International Journal of Technology Assessment in Health Care (publishedVersion)
- PubMed (publishedVersion)
- HAL (submittedVersion)
- UCL Discovery (University College London) (submittedVersion)
- Topics
- Social Sciences › Decision Sciences › Statistics, Probability and Uncertainty › Meta-analysis and systematic reviews
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Epidemiology
- Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods in Clinical Trials
- Keywords
- meta-analysis, median survival time, survival rate, hazard ratio, individual patient data, time-to-event outcomes, cancer survival, surrogate measures
- MeSH terms
- Data Interpretation, Statistical, Humans, Neoplasms, Retrospective Studies, Meta-Analysis as Topic, Survival Analysis
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