Table 3.

Hazard ratios and 95% confidence intervals associating prescriptions for strong or weak opioids and breast cancer recurrence up to ten years after diagnosis, stratified by ER/ET status, menopausal status, and type of primary therapy among women with stage I, II, or III breast cancer in Denmark (1996–2008).

Statistical model and variable analyzed	Total recurrences n (%)	Crude hazard ratio (95% CI)	Adjusted hazard ratio (95% CI)*
Stratified models
Total no. recurrences analyzed	5,325	NA	NA
ER/ET status
ER+/ET+	2,464 (46)	1.1 (0.96 - 1.2)	1.0 (0.93 - 1.2)
ER+/ET−	1,301 (24)	0.89 (0.76 - 1.0)	1.0 (0.86 - 1.2)
ER−/ET−	1,332 (25)	0.96 (0.82 - 1.1)	0.95 (0.81 - 1.1)
Menopausal status
Premenopausal	1,615 (30)	0.98 (0.84 - 1.1)	0.97 (0.83 - 1.1)
Postmenopausal	3,709 (70)	0.98 (0.90 - 1.1)	1.0 (0.92 - 1.1)
Type of primary therapy
Mastectomy	3,706 (70)	0.98 (0.90 - 1.1)	1.0 (0.93 - 1.1)
BCS + RT	1,618 (30)	0.90 (0.78 - 1.0)	0.96 (0.83 - 1.1)
Receipt of chemotherapy
No	3,483 (65)	0.99 (0.91 – 1.1)	1.0 (0.94 – 1.1)
Yes	1,843 (35)	0.97 (0.84 – 1.1)	0.93 (0.80 – 1.1)

^*Adjusted for age at diagnosis (as a continuous variable), menopausal status at diagnosis (pre- or post-menopausal), stage (I, II, or III), histologic grade (low, moderate, high), surgery type and radiotherapy receipt (mastectomy, breast-conserving surgery with radiotherapy), ER status and endocrine therapy receipt (ER+/ET−, ER+/ET−, ER−/ET−, ER−/ET+), receipt of chemotherapy (yes/no), post-diagnostic simvastatin use and post-diagnostic aspirin use (both as time-varying covariates lagged by one year and updated yearly), pre-diagnostic HRT (yes/no), myocardial infarction and congestive heart failure (yes/no), peripheral and cerebrovascular disease (yes/no), malignant disease (yes/no), diabetes mellitus (yes/no), rheumatoid arthritis (yes/no), and osteoarthritis (yes/no).

^§Excluded from the models that were stratified on these factors.