Metformin does not affect cancer risk: A cohort study in the U.K. clinical practice research datalink analyzed like an intention-to-treat trial

Konstantinos K. Tsilidis, Despoina Capothanassi, Naomi E. Allen, Evangelos C. Rizos, David Lopez, Karin Van Veldhoven, Carlotta Sacerdote, Deborah Ashby, Paolo Vineis, Ioanna Tzoulaki, John P.A. Ioannidis

Research output: Contribution to journalArticle

96 Scopus citations

Abstract

OBJECTIVE: Meta-analyses of epidemiologic studies have suggested that metformin may reduce cancer incidence, but randomized controlled trials did not support this hypothesis. RESEARCH DESIGN AND METHODS A retrospective cohort study, Clinical Practice Research Datalink, was designed to investigate the association between use of metformin compared with other antidiabetes medications and cancer risk by emulating an intention-to-treat analysis as in a trial. A total of 95,820 participants with type 2 diabetes who started taking metformin and other oral antidiabetes medications within 12 months of their diagnosis (initiators) were followed up for first incident cancer diagnosis without regard to any subsequent changes in pharmacotherapy. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HR) and 95% CI. RESULTS: A total of 51,484 individuals (54%) were metformin initiators and 18,264 (19%) were sulfonylurea initiators, and 3,805 first incident cancers were diagnosed during a median follow-up time of 5.1 years. Compared with initiators of sulfonylurea, initiators of metformin had a similar incidence of total cancer (HR 0.96; 95% CI 0.89-1.04) and colorectal (HR 0.92; 95% CI 0.76-1.13), prostate (HR 1.02; 95% CI 0.83-1.25), lung (HR 0.85; 95% CI 0.68-1.07), or postmenopausal breast (HR 1.03; 95% CI 0.82-1.31) cancer or any other cancer. CONCLUSIONS: In this large study, individualswith diabetes who usedmetformin had a similar risk of developing cancer compared with those who used sulfonylureas.

Original languageEnglish (US)
Pages (from-to)2522-2532
Number of pages11
JournalDiabetes care
Volume37
Issue number9
DOIs
StatePublished - Jan 1 2014
Externally publishedYes

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ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Advanced and Specialized Nursing

Cite this

Tsilidis, K. K., Capothanassi, D., Allen, N. E., Rizos, E. C., Lopez, D., Van Veldhoven, K., Sacerdote, C., Ashby, D., Vineis, P., Tzoulaki, I., & Ioannidis, J. P. A. (2014). Metformin does not affect cancer risk: A cohort study in the U.K. clinical practice research datalink analyzed like an intention-to-treat trial. Diabetes care, 37(9), 2522-2532. https://doi.org/10.2337/dc14-0584