Table 4

Secondary analyses: Cox proportional hazards model estimates for the subcohort of patients in the highest quartile of insulin dose: overall and stratified by age-group

Highest doseBreast cancerColon cancerPancreatic cancerProstate cancerAny incident cancer
HR95% CIHR95% CIHR95% CIHR95% CIHR95% CI
All ages
 Glargine insulin1.00(0.57–1.76)1.17(0.69–2.00)0.73(0.26–2.06)0.87(0.46–1.64)0.98(0.83–1.15)
 Combination insulin1.75(1.10–2.78)*0.33(0.13–0.80)*0.34(0.08–1.43)0.75(0.37–1.5)0.94(0.79–1.11)
 Metformin use1.34(0.88–2.04)0.84(0.5–1.43)1.42(0.66–3.04)0.42(0.21–0.85)*1.02(0.88–1.17)
 Tobacco exposure1.24(0.81–1.89)1.27(0.82–1.97)1.35(0.67–2.75)0.88(0.53–1.46)1.17(1.03–1.33)*
Aged >75 years
 Glargine insulin0.92(0.44–1.95)0.99(0.49–2.01)0.65(0.15–2.81)0.44(0.16–1.22)1.01(0.81–1.26)
 Combination insulin1.19(0.62–2.29)0.39(0.14–1.09)ID0.78(0.33–1.83)0.91(0.72–1.14)
 Metformin use1.24(0.68–2.24)0.80(0.39–1.62)0.99(0.29–3.44)0.68(0.31–1.52)1.11(0.91–1.35)
Aged ≤75 years
 Glargine insulin1.09(0.46–2.61)1.46(0.64–3.34)0.84(0.19–3.72)1.80(0.76–4.24)0.93(0.73–1.2)
 Combination insulin2.87(1.47–5.59)0.19(0.03–1.37)0.73(0.16–3.26)0.76(0.23–2.56)0.97(0.75–1.24)
 Metformin use1.41(0.77–2.58)0.93(0.42–2.06)1.79(0.65–4.91)0.18(0.04–0.76)*0.95(0.78–1.15)
  • Calculated mean daily dose: 119 units/day. Reference insulin use is nonglargine only. We also adjusted for age category, race/ethnicity, diabetes complications, obesity diagnosis, oral estrogen use, Part D low-income subsidy (a poverty indicator),14 Charlson comorbidities, and tobacco exposure diagnosis. All ages, N = 20,415: 11.7% glargine users, 75.3% nonglargine users, and 13.0% combination users. Age reference group = 68–69 years. Event counts for this subcohort presented in Table 2. Aged >75 years, N = 11,580. Cancer events for this cohort: breast 76, colon 73, pancreas 21, prostate 60, and any 726. Age reference group = 76–80 years. Aged ≤75 years, N = 8,835. Cancer events for this cohort: breast 54, colon 40, pancreas 19, prostate 34, and any 626. ID, insufficient count for analysis.

  • *P < 0.05.

  • P < 0.001.

  • P < 0.01.