Table 1.
Determinants of non-adherence to adjuvant endocrine treatment in Swedish women diagnosed with ER-positive breast cancers, stage I–III between 1 July 2006 and 30 June 2009
| Characteristics | Adherent (N = 3 668) | Non-adherent (N = 977) | OR (95% CI) | ||||
|---|---|---|---|---|---|---|---|
| No. | % | No. | % | Unadjusted | Adjusted for age | Adjusted for age and education | |
| Patient-related | |||||||
| Age at diagnosis (years) | |||||||
| < 50 | 685 | 18.7 | 186 | 19.0 | 1.13 (0.93–1.37) | – | – |
| 50–64 | 1630 | 44.4 | 392 | 40.1 | 1.0 (Ref) | ||
| ≥ 65 | 1353 | 36.9 | 399 | 40.8 | 1.23 (1.05–1.43) | ||
| Menopausal status | |||||||
| Premenopausal | 723 | 19.7 | 196 | 20.1 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Postmenopausal | 2610 | 71.2 | 714 | 73.1 | 1.01 (0.85–1.21) | 1.27 (0.94–1.72) | 1.28 (0.95–1.73) |
| Unknown | 335 | 9.1 | 67 | 6.9 | – | – | – |
| Baseline CCI | |||||||
| 0 | 3121 | 85.1 | 809 | 82.8 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| 1 | 355 | 9.7 | 108 | 11.1 | 1.17 (0.93–1.47) | 1.14 (0.90–1.43) | 1.15 (0.90–1.44) |
| 2 | 130 | 3.5 | 36 | 3.7 | 1.07 (0.72–1.54) | 0.98 (0.66–1.43) | 0.99 (0.67–1.44) |
| 3+ | 62 | 1.7 | 24 | 2.5 | 1.49 (0.91–2.37) | 1.37 (0.83–2.20) | 1.40 (0.85–2.24) |
| FU CCI | |||||||
| 0 | 2650 | 72.2 | 647 | 66.2 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| 1 | 553 | 15.1 | 180 | 18.4 | 1.33 (1.10–1.61) | 1.30 (1.07–1.58) | 1.31 (1.08–1.59) |
| 2 | 277 | 7.6 | 86 | 8.8 | 1.27 (0.98–1.64) | 1.21 (0.92–1.57) | 1.22 (0.93–1.58) |
| 3+ | 188 | 5.1 | 64 | 6.6 | 1.39 (1.03–1.87) | 1.29 (0.94–1.74) | 1.30 (0.95–1.76) |
| Increase in CCI | |||||||
| 0 | 3021 | 82.4 | 767 | 78.5 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| 1 | 440 | 12.0 | 129 | 13.2 | 1.15 (0.93–1.42) | 1.10 (0.88–1.37) | 1.11 (0.89–1.37) |
| 2+ | 207 | 5.6 | 81 | 8.3 | 1.54 (1.17–2.01) | 1.43 (1.08–1.88) | 1.43 (1.08–1.88) |
| Prediagnostic HRT | |||||||
| No | 3393 | 92.5 | 849 | 86.9 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 275 | 7.5 | 128 | 13.1 | 1.86 (1.48–2.32) | 1.99 (1.58–2.49) | 1.98 (1.58–2.48) |
| Baseline analgesics | |||||||
| No | 2748 | 74.9 | 702 | 71.9 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 920 | 25.1 | 275 | 28.1 | 1.17 (1.00–1.37) | 1.16 (0.99–1.36) | 1.17 (1.00–1.37) |
| Baseline hypnotics and sedatives | |||||||
| No | 3189 | 86.9 | 808 | 82.7 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 479 | 13.1 | 169 | 17.3 | 1.39 (1.15–1.68) | 1.38 (1.14–1.67) | 1.37 (1.13–1.66) |
| Baseline antidepressants | |||||||
| No | 3301 | 90.0 | 868 | 88.8 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 367 | 10.0 | 109 | 11.2 | 1.13 (0.90–1.41) | 1.13 (0.90–1.42) | 1.13 (0.90–1.42) |
| Baseline GI drugs | |||||||
| No | 2928 | 79.8 | 834 | 85.4 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 740 | 20.2 | 143 | 14.6 | 0.68 (0.56–0.82) | 0.68 (0.55–0.83) | 0.68 (0.55–0.83) |
| Baseline vaginal oestrogen | |||||||
| No | 3577 | 97.5 | 948 | 97.0 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 91 | 2.5 | 29 | 3.0 | 1.20 (0.77–1.81) | 1.18 (0.75–1.78) | 1.17 (0.75–1.78) |
| Socioeconomic factors | |||||||
| Marital status | |||||||
| Married | 2008 | 54.7 | 437 | 44.7 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Single/divorced/widowed | 1656 | 45.1 | 539 | 55.2 | 1.50 (1.30–1.72) | 1.42 (1.23–1.64) | 1.42 (1.23–1.64) |
| Unknown | 4 | 0.1 | 1 | 0.1 | – | – | – |
| Education | |||||||
| Low | 900 | 24.5 | 225 | 23.0 | 1.0 (Ref) | 1.0 (Ref) | – |
| Medium | 1503 | 41.0 | 399 | 40.8 | 1.06 (0.88–1.28) | 1.17 (0.97–1.42) | – |
| High | 1241 | 33.8 | 345 | 35.3 | 1.11 (0.92–1.34) | 1.25 (1.02–1.53) | – |
| Unknown | 24 | 0.7 | 8 | 0.8 | – | – | – |
| Health system related | |||||||
| Region | |||||||
| Stockholm–Gotland | 1376 | 37.5 | 446 | 45.6 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Uppsala-Örebro | 1751 | 47.7 | 431 | 44.1 | 0.76 (0.65–0.88) | 0.74 (0.64–0.86) | 0.75 (0.64–0.87) |
| Northern Sweden | 541 | 14.7 | 100 | 10.2 | 0.57 (0.45–0.72) | 0.58 (0.45–0.73) | 0.59 (0.46–0.74) |
| Hospital type for surgery | |||||||
| University hospital | 1004 | 27.4 | 244 | 25.0 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Other hospitals | 2655 | 72.4 | 732 | 74.9 | 1.13 (0.97–1.34) | 1.12 (0.95–1.32) | 1.12 (0.96–1.32) |
| Unknown | 9 | 0.2 | 1 | 0.1 | – | – | – |
| Hospital type for follow-up | |||||||
| University hospital | 1452 | 39.6 | 360 | 36.8 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Other hospitals | 2007 | 54.7 | 548 | 56.1 | 1.10 (0.95–1.28) | 1.12 (0.96–1.30) | 1.12 (0.97–1.30) |
| Unknown | 209 | 5.7 | 69 | 7.1 | – | – | - |
| Disease-related | |||||||
| Tumour size (mm) | |||||||
| < 20 | 2255 | 61.5 | 686 | 70.2 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| 20–50 | 1208 | 32.9 | 261 | 26.7 | 0.71 (0.61–0.83) | 0.65 (0.55–0.77) | 0.65 (0.56–0.77) |
| ≥ 50 | 126 | 3.4 | 18 | 1.8 | 0.47 (0.28–0.75) | 0.43 (0.25–0.70) | 0.44 (0.25–0.70) |
| Unknown | 79 | 2.2 | 12 | 1.2 | – | – | – |
| Lymph node metastasis | |||||||
| No | 3103 | 84.6 | 883 | 90.4 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 534 | 14.6 | 79 | 8.1 | 0.52 (0.40–0.66) | 0.51 (0.39–0.65) | 0.51 (0.40–0.65) |
| Unknown | 31 | 0.8 | 15 | 1.5 | – | – | – |
| Tumour grade | |||||||
| I | 827 | 22.5 | 289 | 29.6 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| II | 2022 | 55.1 | 511 | 52.3 | 0.72 (0.61–0.85) | 0.70 (0.59–0.83) | 0.70 (0.59–0.83) |
| III | 747 | 20.4 | 156 | 16.0 | 0.60 (0.48–0.74) | 0.58 (0.47–0.73) | 0.58 (0.47–0.73) |
| Unknown | 72 | 2.0 | 21 | 2.1 | – | – | – |
| PR status | |||||||
| Pr− | 659 | 18.0 | 167 | 17.1 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Pr+ | 2988 | 81.5 | 806 | 82.5 | 1.06 (0.89–1.29) | 1.05 (0.88–1.28) | 1.06 (0.88–1.29) |
| Unknown | 21 | 0.6 | 4 | 0.4 | – | – | – |
| HER2 status | |||||||
| Her2− | 2772 | 75.6 | 725 | 74.2 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Her2+ | 344 | 9.4 | 55 | 5.6 | 0.61 (0.45–0.82) | 0.61 (0.45–0.81) | 0.61 (0.45–0.82) |
| Unknown | 552 | 15.0 | 197 | 20.2 | – | – | - |
| Treatment-related | |||||||
| Type of primary surgery | |||||||
| Sector resection | 2325 | 63.4 | 659 | 67.5 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Mastectomy | 1281 | 34.9 | 304 | 31.1 | 0.84 (0.72–0.97) | 0.75 (0.64–0.87) | 0.75 (0.64–0.87) |
| Other types | 7 | 0.2 | 5 | 0.5 | 2.52 (0.74–7.92) | 2.51 (0.74–7.92) | 2.48 (0.73–7.84) |
| Not operated | 49 | 1.3 | 6 | 0.6 | 0.43 (0.17–0.94) | 0.43 (0.16–0.94) | 0.43 (0.17–0.94) |
| Unknown | 6 | 0.2 | 3 | 0.3 | – | – | – |
| Radiotherapy | |||||||
| No | 1021 | 27.8 | 309 | 31.6 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 2647 | 72.2 | 668 | 68.4 | 0.83 (0.72–0.97) | 0.95 (0.80–1.12) | 0.94 (0.80–1.12) |
| Adjuvant chemotherapy | |||||||
| No | 2577 | 70.3 | 824 | 84.3 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 1091 | 29.7 | 153 | 15.7 | 0.44 (0.36–0.53) | 0.42 (0.35–0.52) | 0.43 (0.35–0.52) |
| Type of endocrine treatment | |||||||
| Tamoxifen only | 1805 | 49.2 | 536 | 54.9 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| AI only | 640 | 17.4 | 138 | 14.1 | 0.73 (0.59–0.89) | 0.72 (0.58–0.89) | 0.72 (0.58–0.89) |
| Tamoxifen + AI | 1223 | 33.3 | 303 | 31.0 | 0.83 (0.71–0.98) | 0.85 (0.73–1.00) | 0.86 (0.73–1.01) |
| First endocrine treatment | |||||||
| Tamoxifen | 757 | 61.9 | 221 | 72.9 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| AI | 466 | 38.1 | 82 | 27.1 | 0.60 (0.45–0.79) | 0.54 (0.41–0.72) | 0.54 (0.41–0.72) |
| ET switch | |||||||
| No | 2445 | 66.7 | 674 | 69.0 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 1223 | 33.3 | 303 | 31.0 | 0.90 (0.77–1.05) | 0.93 (0.79–1.08) | 0.93 (0.80–1.09) |
| FU analgesics | |||||||
| No | 2040 | 55.6 | 450 | 46.1 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 1628 | 44.4 | 527 | 53.9 | 1.47 (1.27–1.69) | 1.41 (1.22–1.63) | 1.43 (1.24–1.66) |
| FU hypnotics and sedatives | |||||||
| No | 2712 | 73.9 | 634 | 64.9 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 956 | 26.1 | 343 | 35.1 | 1.53 (1.32–1.78) | 1.50 (1.28–1.75) | 1.49 (1.28–1.74) |
| FU antidepressants | |||||||
| No | 2852 | 77.8 | 713 | 73.0 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 816 | 22.2 | 264 | 27.0 | 1.29 (1.10–1.52) | 1.27 (1.08–1.49) | 1.27 (1.08–1.50) |
| FU GI drugs | |||||||
| No | 2932 | 79.9 | 726 | 74.3 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 736 | 20.1 | 251 | 25.7 | 1.38 (1.17–1.62) | 1.30 (1.10–1.54) | 1.31 (1.10–1.55) |
| FU vaginal oestrogen | |||||||
| No | 3261 | 88.9 | 836 | 85.6 | 1.0 (Ref) | 1.0 (Ref) | 1.0 (Ref) |
| Yes | 407 | 11.1 | 141 | 14.4 | 1.35 (1.10–1.66) | 1.34 (1.08–1.65) | 1.33 (1.08–1.64) |
OR odds ratio, CI confidence interval, FU follow-up, AI aromatase inhibitors, GI gastro-intestinal