Table 3.

Risk of SBCE, recurrence, and all-cause mortality in relation to diabetes medication classes among women with diabetes in the COMBO cohort (insulin analogues stratified by type)

	SBCE		Recurrence		All-cause mortality
	HR	95% CI	HR	95% CI	HR	95% CI
Diabetes medication classes
Long-acting insulin only	7.10	(0.85–59.2)	13.9	(1.58–122)	4.95	(1.10–22.2)
Short-/rapid-acting insulin only	1.58	(0.91–2.75)	2.07	(1.12–3.81)	1.93	(1.38–2.71)
Both long- and short-/rapid-acting insulin	2.23	(0.64–7.75)	3.62	(1.02–12.9)	3.24	(1.83–5.73)
Metformin	1.00	(0.57–1.77)	1.08	(0.56–2.06)	0.59	(0.40–0.85)
Sulfonylureas	1.00	(0.59–1.70)	0.99	(0.54–1.81)	1.10	(0.79–1.53)

Abbreviations: SBCE second breast cancer event (recurrence and second primary BC), HR hazard ratio, CI confidence interval

Note: all hazard ratios for individual diabetes medication classes are adjusted for other medication classes of interest (ever/never use, time-varying); age at diagnosis (18–49, 50–59, 60–69, 70–79, 80+ years); diagnosis year (1990–1994, 1995–1999, 2000–2004, 2005–2008); AJCC stage (I, IIA, IIB); hormone receptor status (estrogen receptor [ER]−/progesterone receptor [PR]−, ER +/PR−, ER−/PR +, ER +/PR +, and ER and/or PR unknown); primary treatment for initial BC (mastectomy, breast conserving surgery with radiation, breast conserving surgery without radiation); endocrine therapy for the incident BC (yes/no, time-varying); body mass index (BMI) at diagnosis (<25.0, 25.0–29.9, 30.0–34.9, 35+ kg/m²); smoking status at diagnosis (current, past, never/unknown); menopausal status at diagnosis (peri- or premenopausal, postmenopausal); Charlson co-morbidity score (<2, 2+, time-varying); statin use (yes/no, time-varying); prescription non-steroidal anti-inflammatory medication use, Cox-2 inhibitors, and aspirin (yes/no, time-varying); and receipt of screening mammogram in the 12 months prior to events (yes/no, time-varying).