Table 2

Acute/subacute hospital-treated somatic disease incidents: crude incidence rate ratios and treatment contact rate ratios of inpatient days and outpatient hospital contacts

IRR/TCRR (95% CI)p Value
Before versus during OMT, during OMT as reference (incidence rate=1)
 All incidents1.6 (1.3 to 1.9)<0.001
  Drug-related*4.2 (2.9 to 6.2)<0.001
   Overdoses2.8 (1.6 to 5.0)<0.001
   Injecting-related5.9 (3.1 to 11.4)<0.001
   Other5.7 (2.8 to 11.9)<0.001
  Non-drug-related0.7 (0.6 to 1.0)0.02
  Injuries1.2 (0.9 to 1.5)0.23
 Inpatient days
  Drug-related6.3 (3.4 to 11.8)<0.001
  Non-drug-related0.5 (0.3 to 1.0)0.04
  Injuries2.1 (0.7 to 5.7)0.17
  All1.7 (1.1 to 2.4)0.01
 Outpatient contacts
  Drug-related4.8 (2.7 to 8.3)<0.001
  Non-drug-related0.7 (0.4 to 1.2)0.18
  Injuries1.1 (0.7 to 1.6)0.78
  All1.4 (1.0 to 1.8)0.04
After versus during OMT, during OMT as reference (incidence rate=1)
 All incidents2.8 (2.1 to 3.9)<0.001
  Drug-related11.1 (6.6 to 18.5)<0.001
   Overdoses5.8 (2.7 to 12.3)<0.001
   Injecting-related12.6 (4.3 to 36.8)<0.001
   Other16.7 (6.5 to 42.7)<0.001
  Non-drug-related1.4 (0.9 to 2.2)0.15
  Injuries0.8 (0.3 to 1.8)0.57
 Inpatient days
  Drug-related25.2 (13.1 to 48.7)<0.001
  Non-drug-related1.1 (0.5 to 2.3)0.78
  Injuries4.6 (0.8 to 28.5)0.98
  All5.9 (3.6 to 9.6)<0.001
 Outpatient contacts
  Drug-related10.6 (4.7 to 25.9)<0.001
  Non-drug-related1.6 (0.7 to 3.7)0.26
  Injuries1.1 (0.4 to 3.1)0.87
  All2.0 (1.1 to 3.8)0.03

  • The incidence rate ratios indicate the statistical significance of the changes in incidence rates demonstrated in table 1, estimated by Poisson regression (generalised estimating equations). Patient-years at risk: 1000 before, 813 during and 91 after OMT. Number of incidents: 605 before, 310 during and 106 after OMT.

  • IRR, incidence rate ratios; OMT, opioid maintenance treatment; TCRR, treatment contact rate ratios.

  • * Subgroups in italic.