Systematic reviewindependent cross-checkabstract checked★ key study I-INS-126 in-depth review

How good is the evidence on long-acting insulin and cancer?

Effect of Long-Acting Insulin Analogs on the Risk of Cancer: A Systematic Review of Observational Studies.

Overview

Wu JW et al.. Diabetes Care 2016 · PMID 26740633 · DOI 10.2337/dc15-1816

Most studies found no cancer increase; a few suggested more breast cancer, but many studies had design flaws.

Does the study support the specific claim? Partly · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Review observational studies on insulin analogues and cancer.
How was the study done?: Systematic review.
How many people, animals or samples were studied?: 19 studies.
What was actually found?: 13/15 null for any cancer; 4/13 positive for breast cancer.
How large was the observed effect?: Not pooled.
What do the results mean in everyday life?: No clear cancer risk; breast cancer still uncertain.
What are the study's limitations?: Short follow-up in included studies.
What does it say about Elawady's specific claim?: Does not support dose-dependent cancer; leaves breast question open.
Do the results apply to Germany and Europe?: Applicable.
What can explicitly not be concluded from this study?: Cannot settle long-term breast cancer risk.

Are long-acting insulin analogues associated with cancer, and how reliable are the studies?

Study design: Systematic review – Systematic review of observational studies with methodological assessment
Population: People with T1D or T2D
Country: Multinational
Period: 2000-2014
Sample size: 16 cohort and 3 case-control studies
Inclusion and exclusion criteria: English-language cohort/case-control studies on glargine/detemir

Results: Follow-up 0.9-7.0 years; 13 of 15 studies found no association with any cancer; 4 of 13 found increased breast cancer risk with glargine. Methodological issues: prevalent users (7), no lag period (11), time-related biases (6), short follow-up <5 years (16).
Absolute risks: not reported
Authors' conclusion: Observational studies have important methodological shortcomings; uncertainty remains, particularly for breast cancer.

Vote count; not pooled.

Overall cancer: mostly null; breast cancer: unresolved.

Directly applicable; same biology and clinical standards in Europe.

Explains why the breast-cancer question remains open.

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