Cohort studyindependent cross-checkabstract checked I-ODD-125 standard review

European data: no bladder cancer increase with pioglitazone over about 3 years

Pioglitazone use and risk of bladder cancer in patients with type 2 diabetes: retrospective cohort study using datasets from four European countries.

Overview

Korhonen P et al.. BMJ 2016 · PMID 27530399 · DOI 10.1136/bmj.i3903

aHR 0.99 (0.75-1.30).

Does the study support the specific claim? No · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Test pioglitazone and bladder cancer in Europe.
How was the study done?: Propensity-matched cohort.
How many people, animals or samples were studied?: 56,337 users.
What was actually found?: No association.
How large was the observed effect?: HR 0.99.
What do the results mean in everyday life?: Results differ between studies; any risk is small.
What are the study's limitations?: Short follow-up, industry funding.
What does it say about Elawady's specific claim?: Contradicts a general 63% increase.
Do the results apply to Germany and Europe?: Direct.
What can explicitly not be concluded from this study?: Long-term risk.

Authors: Korhonen P et al.
Journal: BMJ
Year: 2016
Identifier: PMID 27530399 DOI 10.1136/bmj.i3903
Verification: verified – PubMed efetch 2026-10-26; Crossref works API 2026-10-26
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: Fully funded by Takeda (marketing authorisation holder), mandated by EMA; authors employed by research organisations doing commissioned studies (full-text disclosure read).

Is pioglitazone associated with bladder cancer in type 2 diabetes?

Study design: Cohort study – Retrospective propensity-matched cohort in four European countries (EMA-mandated post-authorisation study)
Population: Patients with type 2 diabetes in Finland, Netherlands, Sweden, UK
Country: Finland, Netherlands, Sweden, UK
Period: Mean follow-up about 2.9 years
Sample size: 56,337 pioglitazone users; 317,109 matched non-users
Inclusion and exclusion criteria: New pioglitazone users matched on treatment history and propensity score

Results: 130 bladder cancers in exposed. aHR 0.99 (0.75-1.30) nearest match; 1.00 (0.83-1.21) multiple match. >48 months use HR 0.86 (0.44-1.66); >40,000 mg cumulative dose HR 0.65 (0.33-1.26).
Absolute risks: Not reported in abstract.
Authors' conclusion: No evidence of an association between pioglitazone and bladder cancer.

Orienting tool: ROBINS-E
Type of assessment: simplified assessment (abstract only)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Short follow-up limits ability to detect latency-dependent effects; industry funding.

CI log-symmetric (stats/C-ODD-12.py).

EU data not reproducing an increased risk; weaker because of short follow-up and sponsor funding.

Tuccori 2016 (A-ODD-03).

Direct (EU).

Adds to inconsistency across cohorts.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	mixed
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

Long latency.