Table 3

Incidence rate and rate ratio for cancer among patients who used antidiabetic medications and those who did not use antidiabetic drugs

Cancer site	Number of cases	Woman-years	Crude rate (per 1000)	95% CI
Breast cancer
Metformin only	143	28 571	5.01	4.22 to 5.90
Metformin+sulfonylureas	215	57 577	3.73	3.25 to 4.27
Metformin+insulin	6	2613	2.30	0.84 to 5.00
Metformin and other diabetic meds	339	67 723	5.01	4.49 to 5.57
Sulfonylureas only	55	24 316	2.26	1.70 to 2.94
Insulin only	125	32 658	3.83	3.19 to 4.56
Other non-metformin drugs only	46	8560	5.37	3.93 to 7.17
Non-antidiabetic users	643	162 820	3.95	3.65 to 4.27
Endometrial cancer
Metformin only	36	28 571	1.26	0.88 to 1.74
Metformin+sulfonylureas	60	57 577	1.04	0.80 to 1.34
Metformin+insulin	1	2613	0.38	0.01 to 2.13
Metformin and other diabetic meds	71	67 723	1.05	0.82 to 1.32
Sulfonylureas only	6	24 316	0.25	0.09 to 0.54
Insulin only	33	32 658	1.01	0.70 to 1.42
Other non-metformin drugs only	11	8560	1.29	0.64 to 2.30
Non-antidiabetic users	130	162 820	0.80	0.67 to 0.95
Ovarian cancer
Metformin only	5	28 571	0.18	0.06 to 0.41
Metformin+sulfonylureas	20	57 577	0.35	0.21 to 0.54
Metformin+insulin	0	2613
Metformin and other diabetic meds	29	67 723	0.43	0.29 to 0.61
Sulfonylureas only	11	24 316	0.45	0.23 to 0.81
Insulin only	12	32 658	0.37	0.19 to 0.64
Other non-metformin drugs only	7	8560	0.82	0.33 to 1.68
Non-antidiabetic users	79	162 820	0.49	0.38 to 0.60
All cancers combined
Metformin only	184	28 571	6.44	5.54 to 7.44
Metformin+sulfonylureas	295	57 577	5.12	4.56 to 5.74
Metformin+insulin	7	2613	2.68	1.08 to 5.52
Metformin and other diabetic meds	439	67 723	6.48	5.89 to 7.12
Sulfonylureas only	72	24 316	2.96	2.32 to 3.73
Insulin only	170	32 658	5.21	4.45 to 6.05
Other non-metformin drugs only	64	8560	7.48	5.76 to 9.55
Non-antidiabetic users	852	162 820	5.23	4.89 to 5.60