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Table 4 Sensitivity analysis of association between statin use and breast cancer-specific and all-cause mortality in patients with breast cancer

From: Statin use and breast cancer survival: a nationwide cohort study in Scotland

  Medication user Medication non-user Age-adjusted HR (95 % CI) P Adjusted HR (95 % CI) P P interaction
Cancer\all mortality Patients Person years Cancer\all mortality Patients Person years
Cancer-specific mortality
 Subgroup analyses: Statin users versus non-usersa
  Stage 1–2 111 3,185 8,085 310 8,467 24,768 0.86 (0.69,1.08) 0.21 0.91 (0.68,1.21) 0.51  
  Stage 1–3 209 3,671 9,224 555 10,793 28,147 0.91 (0.77,1.08) 0.29 1.02 (0.83,1.26) 0.85
  Diagnosed 2009–2010 207 2,187 6,820 569 5,211 19,746 0.79 (0.67,0.93) 0.06 0.77 (0.60,0.98) 0.04 0.08
  Diagnosed 2011–2012 128 2,046 3,601 286 5,696 11,106 1.03 (0.83,1.28) 0.77 1.35 (0.98,1.85) 0.06
  Estrogen receptor positive 243 3,655 9,079 552 8,995 25,600 0.88 (0.75,1.03) 0.11 0.92 (0.72,1.16) 0.48  
  Estrogen receptor negative 87 514 1197 279 1710 4705 0.95 (0.73,1.23) 0.69 1.06 (0.76,1.48) 0.72  
  Hormone receptors availableb 212 2610 6193 550 6918 18682 0.89 (0.75,1.05) 0.18 0.98 (0.77,1.25) 0.89  
  Using 1 year lagc 320 4067 9695 870 11073 31578 0.91 (0.80,1.04) 0.18 1.00 (0.78,1.28) 0.99  
 Adjusted for competing risk of deathd
  Statin 335 4,233 10,421 855 10,907 30,852 0.88 (0.78, 1.00) 0.07 0.98 (0.81, 1.19) 0.88  
  Simvastatin 224 3,025 7,428 966 12,115 33,845 0.83 (0.72, 0.97) 0.02 0.91 (0.75, 1.12) 0.38  
 Use in first year after diagnosise
  Statin user versus non-user 318 3,624 9,555 872 11,516 31,718 0.89 (0.78,1.02) 0.10 0.99 (0.82,1.21) 0.95  
  Simvastatin user versus non-user 210 2,470 6,569 980 12,670 34,704 0.86 (0.74,1.00) 0.05 0.95 (0.78,1.17) 0.65  
All-cause mortality
 Subgroup analyses: Statin users versus non-usersa
  Stage 1–2 297 3,185 8,085 554 8,467 24,768 0.99 (0.85,1.14) 0.87 0.89 (0.74,1.06) 0.20  
  Stage 1–3 437 3,671 9,224 859 10,793 28,147 0.98 (0.87,1.10) 0.72 0.91 (0.78,1.06) 0.24
  Diagnosed 2009–2010 456 2,187 6,820 871 5,211 19,746 0.94 (0.83,1.05) 0.26 0.79 (0.66,0.94) 0.01 0.38
  Diagnosed 2011–2012 228 2,046 3,601 452 5,696 11,106 0.97 (0.82,1.14) 0.71 1.02 (0.79,1.30) 0.89
  Estrogen receptor positive 549 3,655 9,079 946 8,995 25,600 0.98 (0.88,1.09) 0.70 0.85 (0.72,1.01) 0.06  
  Estrogen receptor negative 119 514 1197 324 1710 4705 0.99 (0.79,1.24) 0.92 1.00 (0.74,1.34) 0.98  
  Hormone receptors availableb (and adjusted for) 400 2610 6193 806 6918 18682 0.95 (0.84,1.08) 0.43 0.89 (0.74,1.07) 0.23  
  Using 1 year lagc 648 4067 9695 1359 11073 31578 0.97 (0.88,1.07) 0.54 0.91 (0.75,1.10) 0.33  
  Cardiovascular deaths 142 4233 10421 132 10907 30852 3.21 (2.53,4.06) <0.001 1.07 (0.73,1.55) 0.74  
  Non-cardiovascular deaths 542 4233 10421 1191 10907 30852 1.36 (1.23,1.50) <0.001 0.86 (0.74,1.00) 0.06  
 Use in first year after diagnosise
  Statin user versus non-user 649 3,624 9,555 1,358 11,516 31,718 0.97 (0.88,1.07) 0.55 0.91 (0.79,1.06) 0.23  
  Simvastatin user versus non-user 445 2,470 6,569 1,562 12,670 34,704 0.96 (0.86,1.07) 0.47 0.89 (0.77,1.04) 0.15  
  1. aBased upon main time varying covariate analysis adjusted model contains age, year of diagnosis, socioeconomic status, stage, grade, cancer treatment within 6 months (radiotherapy, chemotherapy, surgery), comorbidities (prior to diagnosis, including acute myocardial infarction, congestive heart disease, peripheral vascular disease, cerebral vascular accident, pulmonary disease, peptic ulcer, liver disease, diabetes, renal disease) hormone replacement therapy use (in year prior to diagnosis) and other prescription medication use (tamoxifen, aromatase inhibitor, low-dose aspirin, and metformin as time varying covariates)
  2. bModel contains all variables in a along with estrogen, progesterone and HER2 receptor status, where available
  3. cStatin use modelled as a time varying covariate with a 1 year lag. Model contains all variables in 1 with prescription medication use all modelled with a 1 year lag (tamoxifen, aromatase inhibitor, low-dose aspirin use and metformin)
  4. dReported estimates are subdistribution hazard ratios and 95 % CIs
  5. eModel contains age, year of diagnosis, deprivation, stage, grade, cancer treatment within 6 months (radiotherapy, chemotherapy, surgery), comorbidities (prior to diagnosis, including acute myocardial infarction, congestive heart disease, peripheral vascular disease, cerebral vascular accident, pulmonary disease, peptic ulcer, liver disease, diabetes, renal disease) hormone replacement therapy use (in year prior to diagnosis) and other prescription medication use in the first year after diagnosis (tamoxifen, aromatase inhibitor, low-dose aspirin use and metformin)