Meta-analysis of cancer risk among users of insulin glargine.

Abstract

Listen

Translate article

1510 Background: The association between diabetes, its risk factors and treatments, and cancer risk and death is now high on the clinical and research agenda. Methods: All data regarding cancer risk and use of insulin glargine has been assembled and meta-analyses performed using state-of-the-art statistical methodology. Glargine is the most studied insulin in this regard. A random effects model was employed with tests for heterogeneity (I2) and publication bias. These meta-analyses are based on reports from epidemiological studies involving a total of 907,008 diabetic subjects and 2,597,602 person-years of observation. Results: Based on independent estimates from 14 studies, the Summary Relative Risk (SRR) for all forms of cancer was (SRR=0.90, 95% CI (0.82, 0.98)) and for breast cancer SRR=1.14 (95% CI (1.00, 1.29)). For new users of glargine, from 7 studies, the SRR for breast cancer was SRR=1.20 (95% CI (0.90, 1.58)). Based on independent estimates for 9 studies, for colorectal cancer the SRR was 0.73 (95% CI (0.59, 0.91)) and for prostate cancer SRR=1.16 (95% CI (1.03, 1.30)). Overall, the risk of developing cancer among users of insulin glargine is reduced compared to the risk of users of other insulins. Similarly, the risk of colorectal cancer is reduced among users of glargine. While above unity, the risks of breast cancer and prostate cancer are increased marginally. Potential limitations to this meta-analysis include that the comparison group was not the same in all studies but this could also be seen as a strength. This is not likely to invalidate the findings of this analysis nor would the fact that different adjustments were made in the individual studies. Conclusions: The current evidence gives no support to the hypothesis that insulin glargine is associated with an increased risk of cancer as compared to other insulins and should give reassurance to physicians and their patients. Given the short exposure time possible to glargine (less than 5 years maximum), it is not biologically plausible to have a causal link to common forms of cancer.