ArticlePharmacoepidemiology and drug safety2026
Effectiveness of Metformin in Preventing Colorectal Cancer Among Japanese Patients With Type 2 Diabetes: A Target Trial Emulation.
Article in Pharmacoepidemiology and drug safety, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
purposeObservational studies have repeatedly reported lower cancer incidence among metformin users than nonusers, but findings are inconsistent and often affected by issues such as immortal time, unclear comparators, and use of total cancer as a composite outcome, which precludes adequate adjustment for site-specific confounding. These limitations can be mitigated by explicitly emulating a target trial with a suitable active comparator.
methodsWe emulated a target trial using a Japanese claims database (April 2014-March 2024) to assess whether metformin reduces colorectal cancer (CRC) risk compared with dipeptidyl peptidase-4 inhibitors (DPP-4is) in patients with type 2 diabetes. DPP-4is served as an active comparator because they are widely used as first-line alternatives in Japan and have no clear evidence of affecting CRC risk. We estimated the observational analogue of the per-protocol effect using pooled logistic regression with inverse probability weighting to adjust for baseline and time-varying confounders.
resultsAmong 26 273 metformin users and 108 299 DPP-4i users, the 5-year risk of CRC was 1.55% (95% confidence interval, 1.16 to 2.04) versus 1.26% (1.13 to 1.41), yielding a risk difference of 0.29% (-0.12 to 0.79) and a risk ratio of 1.23 (0.91 to 1.66).
conclusionsMetformin use did not reduce the 5-year risk of CRC compared with DPP-4is. This finding is consistent with meta-analyses of randomized trials and contrasts with earlier observational reports of substantial benefit, which were likely inflated by methodological flaws. Explicitly emulating a target trial minimized design-related biases and provided estimates that support causal interpretation.
Indexed as
Identifiers
What Socratic holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.