The objective of this study was to compare the risks of breast cancer in women treated with insulin glargine and NPH using claims data. The MarketScan and Clinformatics databases were used to identify patients prescribed glargine or NPH in the study periods of January 2007 to March 2016 and July 20to June 2016, respectively. The risks of breast cancer in patients prescribed glargine relative to NPH were compared using three approaches: (1) on-treatment, (2) intent-to-treat and (3) time-dependent analysis. The overall and follow-up period stratified adjusted hazard ratios (aHRs) for breast cancer for glargine compared to NPH were obtained using Cox proportional hazards modelling controlling for potential confounders.In the MarketScan database, 75,422 glargine and 21,491 NPH patients were identified, of which 42,491 glargine and 7,826 NPH patients were new users. Using the Clinformatics database, 65,648 glargine and 16,194 NPH patients were identified, including 47,118 and 10,560 new users, respectively. The overall aHRs for breast cancer for glargine compared to NPH ranged from 0.90 (95% CI: 0.76-1.07) in the time-dependent analysis for all users in the Clinformatics database to 1.30 (95% CI: 0.76-2.25) in the on-treatment analysis for new users in the MarketScan database. In the MarketScan database, the aHRs stratified by the follow-up period (< 1, 1 - < 3, 3 - < 5 and ≥ 5 Years) ranged from 0.67 to 1.63. In the Clinformatics database the corresponding aHRs ranged from 0.85 to 1.40. All 95% confidence intervals (CIs) included the null value of 1. These findings suggest that the risk of breast cancer in patients prescribed glargine was not different from that in NPH patients.

In conclusion, the risks of breast cancer were not different between patients prescribed glargine and NPH. Additionally, no association between glargine and breast cancer was observed with follow-up longer than 5 years.


P. Boyle: Other Relationship; Self; Sanofi. C. Wu: Employee; Self; Sanofi. K. Sharma: Employee; Spouse/Partner; Sanofi US. S.L. Lin: Employee; Self; Sanofi. Employee; Spouse/Partner; Bristol-Myers Squibb Company. J. Juhaeri: Employee; Self; Sanofi. Other Relationship; Spouse/Partner; Sanofi.

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