Table 2.

Multivariate time-dependent Cox regression analysis for the development of cancer.

Multivariate model
VariableHR (95% CI)P
Chronic opioid users (vs. control group): model 11.20 (1.15–1.25)<0.001
Sensitivity analysis: model 2
 Control group1
 Chronic weak opioid users1.18 (1.13–1.23)<0.001
 Chronic strong opioid users1.32 (1.10–1.59)0.003
Other variables in model 1
Age, year1.04 (1.04–1.04)<0.001
Sex, male1.70 (1.65–1.75)<0.001
Income level (deciles distribution ratio)
 1st (lowest income level)1
 2nd1.01 (0.94–1.08)0.859
 3rd1.07 (1.00–1.15)0.050
 4th0.99 (0.93–1.06)0.819
 5th1.05 (0.98–1.12)0.208
 6th1.07 (1.01–1.13)0.027
 7th0.97 (0.91–1.04)0.370
 8th1.00 (0.94–1.06)0.913
 9th1.02 (0.96–1.08)0.592
 10th (highest income level)1.03 (0.97–1.09)0.314
Residence
 Capital city (Seoul)1
 Metropolitan city1.03 (0.99–1.08)0.120
 Other area1.00 (0.96–1.03)0.796
Charlson comorbidity index in 20101.11 (1.10–1.12)<0.001
 Congestive heart failure0.99 (0.94–1.05)0.847
 Chronic pulmonary disease1.12 (1.08–1.15)<0.001
 Cerebrovascular disease1.01 (0.97–1.05)0.847
 Dementia1.03 (0.89–1.19)0.677
 DM with chronic complication1.12 (1.07–1.18)<0.001
 DM without chronic complication1.15 (1.11–1.19)<0.001
 Hemi- or paraplegia0.96 (0.86–1.07)0.469
 Myocardial infarction1.02 (0.93–1.11)0.706
 Mild liver disease1.28 (1.24–1.32)<0.001
 Severe liver disease1.41 (1.27–1.57)<0.001
 Peptic ulcer disease1.13 (1.10–1.16)<0.001
 Peripheral vascular disease1.02 (0.99–1.06)0.256
 Renal disease1.11 (1.00–1.22)0.042
 Rheumatic disease1.08 (1.03–1.14)0.003
Surgery at 20101.06 (1.03–1.09)0.001
Other chronic analgesic use
 Paracetamol1.07 (0.78–1.46)0.686
 Gabapentin1.15 (1.03–1.28)0.014
 Pregabalin1.04 (0.87–1.25)0.653
 NSAIDs1.32 (0.88–1.99)0.182
  • Abbreviation: DM, diabetes mellitus.