Volume 73 Supplement 1

Methods in Epidemiology Symposium

Open Access

Influence of metformin intake on the risk of bladder cancer in type 2 diabetes patients

  • Maria (Mieke) Goossens1,
  • Frank Buntinx1,
  • Maurice Zeegers2,
  • Annemariek Driessen3,
  • Marie De Bruin3 and
  • Frank De Vries3
Archives of Public HealthThe official journal of the Belgian Public Health Association201573(Suppl 1):P3

DOI: 10.1186/2049-3258-73-S1-P3

Published: 17 September 2015

Objective

The aim of this study is to look at the influence of metformin intake and duration, on urinary bladder cancer (UBC) risk, with sulfonylurea (SU) only users as control using a new-user design (inception cohort).

Methods

We conducted a retrospective cohort study using data from the UK Clinical Practice Research Datalink (CPRD) including all patients with at least one prescription of oral anti-diabetic drugs (ADD) and/or insulin and aged 18 years or older. The risk of UBC in different groups of ADD users (metformin alone (1), metformin in combination (2) with other ADD medication (glinides, glitazones, DPP-4-inhibitors, SUs, insulin or more than one combination), all metformin users (1 + 2) was compared with SU only users using Cox proportional hazards models. The estimates were adjusted for age, gender, smoking status, BMI and diabetes duration.

Results

The inception cohort included 165,398 participants of which 132,960 metformin users and 32,438 SU only users. During a mean follow-up time of more than five years 693 patients developed UBC, 124 of the control group and 461 of the all metformin users. There was no association between metformin intake and UBC risk (HR = 1.12 (95% CI 0.90-1.40)) compared to SU only users, even after adjustment for diabetes duration (HR = 1.13 (95% CI 0.90-1.40)). We found a pattern of decreasing risk of UBC with increasing duration of metformin intake, which was statistically not significant.

Conclusion

Metformin has no influence on the risk of UBC compared to SU in type 2 diabetes patients using a new-user design.

Authors’ Affiliations

(1)
KU Leuven
(2)
University Maastricht
(3)
Utrecht University

Copyright

© Goossens et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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