Table 1. Characteristics of oral DM medication users at breast cancer diagnosis.
| During breast cancer treatment period | ||||||
|---|---|---|---|---|---|---|
| All DM medication users a (n=516) | Adherent DM medication users b (n=123) | Non-adherent DM medication users b (n=376) | ||||
| Year of breast cancer diagnosis | ||||||
| 1990-2000 | 302 | (58.5) | 66 | (53.7) | 232 | (61.7) |
| 2001-2004 | 120 | (23.3) | 39 | (31.7) | 77 | (20.5) |
| 2005-2008 | 94 | (18.2) | 18 | (14.6) | 67 | (17.8) |
| Length of cancer treatment period (days) c | ||||||
| Median (IQR) | 110 | (59-185) | 113 | (76-191) | 109 | (57-193) |
| Age (years) | ||||||
| Median (IQR) | 64.3 | (11.4) | 68 | (55-71) | 63 | (56-76) |
| 18-39 | 9 | (1.8) | 1 | (0.8) | 8 | (2.1) |
| 40-49 | 57 | (11.4) | 13 | (10.6) | 44 | (11.7) |
| 50-59 | 116 | (23.2) | 22 | (17.9) | 89 | (23.7) |
| 60-69 | 150 | (30.1) | 32 | (26.0) | 115 | (30.6) |
| 70-79 | 132 | (26.5) | 38 | (30.9) | 91 | (24.2) |
| 80+ | 51 | (10.2) | 17 | (13.8) | 29 | (7.7) |
| Menopausal status | ||||||
| Premenopausal | 105 | (20.3) | 23 | (18.7) | 80 | (21.3) |
| Postmenopausal | 411 | (79.7) | 100 | (81.3) | 296 | (78.7) |
| Race | ||||||
| White | 423 | (82.0) | 107 | (87.0) | 293 | (77.9) |
| African American | 26 | (5.0) | 3 | (2.4) | 23 | (6.1) |
| American Indian / Alaska Native | 20 | (3.9) | 3 | (2.4) | 20 | (5.3) |
| Asian / Pacific Islander | 44 | (8.5) | 9 | (7.3) | 39 | (10.4) |
| Unknown | 3 | 1 | 2 | |||
| Ethnicity | ||||||
| Not Hispanic | 480 | (93.0) | 116 | (94.3) | 347 | (92.3) |
| Hispanic | 36 | (7.0) | 7 | (5.7) | 29 | (7.7) |
| Education | ||||||
| High school or less | 82 | (31.5) | 16 | (13.0) | 46 | (12.2) |
| Some college | 106 | (40.8) | 18 | (14.6) | 65 | (17.3) |
| College or post graduate | 72 | (27.7) | 16 | (13.0) | 50 | (13.3) |
| Unknown | 256 | 73 | 215 | |||
| Body mass index (kg/m2) | ||||||
| Mean (SD) | 32.3 | (6.3) | 33.2 | (7.4) | 31.4 | (6.5) |
| <18.5 | 4 | (0.8) | 2 | (1.6) | 2 | (0.5) |
| 18.5-24.9 | 69 | (13.4) | 12 | (9.8) | 56 | (14.9) |
| 25.0-29.9 | 139 | (26.9) | 33 | (26.8) | 106 | (28.2) |
| 30.0-34.9 | 139 | (26.9) | 31 | (25.2) | 108 | (28.7) |
| 35.0+ | 165 | (32.0) | 50 | (40.7) | 103 | (27.4) |
| Smoking status | ||||||
| Ever | 79 | (15.3) | 17 | (13.8) | 55 | (14.6) |
| Never | 433 | (84.7) | 106 | (86.2) | 321 | (85.4) |
| AJCC stage | ||||||
| I | 318 | (61.6) | 84 | (68.3) | 222 | (59.0) |
| IIA | 138 | (26.7) | 25 | (20.3) | 108 | (28.7) |
| IIB | 60 | (11.6) | 14 | (11.4) | 46 | (12.2) |
| Lymph node status d | ||||||
| Negative | 383 | (74.4) | 82 | (66.7) | 253 | (67.3) |
| Positive | 132 | (25.6) | 22 | (17.9) | 91 | (24.2) |
| Unknown | 1 | 19 | 32 | |||
| Comorbidities | ||||||
| Hypertension | 440 | (85.3) | 104 | (84.5) | 320 | (85.1) |
| Ischemic heart disease | 175 | (35.1) | 53 | (43.1) | 122 | (32.4) |
| Charlson comorbidity index e,h | ||||||
| 0 | 177 | (34.2) | 28 | (22.8) | 175 | (46.5) |
| 1 | 197 | (38.2) | 51 | (41.5) | 118 | (31.4) |
| 2+ | 122 | (23.6) | 37 | (30.1) | 72 | (19.1) |
| Missing (pre-1993) | 20 | 7 | 11 | |||
| Surgical procedure | ||||||
| Mastectomy ± radiation | 195 | (39.7) | 57 | (46.3) | 138 | (36.7) |
| Breast conserving, radiation (+) | 258 | (51.5) | 60 | (48.8) | 191 | (50.8) |
| Breast conserving, radiation (-) | 63 | (12.2) | 13 | (10.6) | 40 | (10.6) |
| Other breast cancer treatments | ||||||
| Chemotherapy h | 153 | (29.7) | 27 | (22.0) | 120 | (31.9) |
| Endocrine therapy | 301 | (58.3) | 65 | (52.8) | 226 | (60.1) |
| Completed 5 years endocrine therapy | 130 | (43.2) | 26 | (40.0) | 104 | (46.0) |
| Chemotherapy + Endocrine therapy | 109 | (21.1) | 16 | (13.0) | 78 | (20.7) |
| # Primary care physician visits within one year post-diagnosis | ||||||
| Mean (SD) | 4.0 | (3.9) | 4.3 | (3.6) | 3.9 | (4.0) |
| 0-1 visit only h | 147 | (28.5) | 28 | (22.8) | 113 | (30.1) |
| ≥2 visits | 369 | (71.5) | 95 | (77.2) | 263 | (69.9) |
| DM medication use | ||||||
| Metformin only | 149 | (28.9) | 38 | (30.9) | 111 | (29.5) |
| Sulfonylureas only | 195 | (37.8) | 48 | (39.0) | 147 | (39.1) |
| Metformin plus sulfonylureas | 165 | (32.0) | 37 | (30.1) | 128 | (34.0) |
| Any DM medication plus insulin | 220 | (42.6) | 39 | (31.7) | 148 | (39.4) |
| Other DM medications only f | 7 | (1.4) | ||||
| # CVD prescriptions used concurrently throughout study period g | ||||||
| 1 medication only | 102 | (19.8) | 23 | (18.7) | 67 | (17.8) |
| ≥2 medications | 414 | (80.2) | 100 | (81.3) | 309 | (82.2) |
| ≥3 medications | 248 | (48.1) | 52 | (42.3) | 195 | (51.9) |
| ≥4 medications h | 150 | (29.1) | 33 | (26.8) | 140 | (37.2) |
Abbreviations: IQR interquartile range, SD standard deviation, AJCC American Joint Committee on Cancer
Note: Values are presented as n (%) unless otherwise noted
≥1 dispensing of oral DM medication in the year prior to breast cancer diagnosis
Post-diagnosis adherence defined as MPR ≥0.80 to metformin/sulfonylureas, breast cancer diagnosis through treatment period
Last date of primary breast cancer treatments (surgery, radiation or chemotherapy)
From SEER registry or chart when missing from SEER
Deyo RA, Cherkin DC, Ciol MA. J Clin Epidemiol. 1992;45: 613-619.
Other DM medications: meglitinides, thiazolidinediones or DPP-4 inhibitors
CVD prescriptions used: highest number through Year +3 of concurrent oral medications to treat DM, dyslipidemias or hypertension
Indicates that differences between adherent and non-adherent users were significant at P<0.05 using χ2 test for categorical variables and Fisher's exact test for continuous variables