Table 4

Influence of readmission for accidental opioid overdose and year of overdose on neurological, respiratory, cardiac and other outcomes evaluated during overdose admission

EventsOpioid overdose readmissionAdmissions in 2015 versus 2006*
Crude ORAdjusted OR
(95% CI)
Crude ORAdjusted OR
(95% CI)
Primary outcome
 Neurological:
 Encephalopathy770.520.57 (0.13 to 2.49)1.120.73 (0.28 to 1.89)
Secondary outcomes
 Respiratory outcomes:
 Respiratory failure1341.100.93 (0.43 to 2.04)3.653.05 (1.15 to 8.08)
 Aspiration pneumonia2880.450.48 (0.21 to 1.08)1.010.88 (0.49 to 1.59)
 ARDS19n/an/an/an/a
 Pulmonary haemorrhage<5n/an/an/an/a
 Cardiac outcomes:
 Cardiac arrest56n/an/an/an/a
 Ventricular arrhythmia5n/an/an/an/a
 Heart failure28n/an/an/an/a
 Other outcomes:
 Rhabdomyolysis1240.640.64 (0.24 to 1.75)1.330.96 (0.38 to 2.43)
 Acute renal failure2371.131.07 (0.60 to 1.91)1.971.86 (0.95 to 3.66)
 Paraplegia or tetraplegia6n/an/an/an/a
 Death in hospital800.770.86 (0.27 to 2.76)0.740.63 (0.24 to 1.65)
 Composite outcome†6370.820.83 (0.54 to 1.26)1.271.08 (0.71 to 1.64)
  • OR estimates have been omitted, and replaced with ‘n/a’ for ‘not available’, for outcomes where estimation was not possible due to a small number of events in one or more exposure groups. 

  • *The ‘Admissions in 2015 versus 2006’ column reports the odds of each outcome occurring in association with an accidental opioid overdose hospitalisation in 2015 when compared with 2006. 

  • †The ‘composite outcome’ was defined as the occurrence of one or more of the following within an admission: encephalopathy, ARDS, respiratory failure, pulmonary haemorrhage, aspiration pneumonia, cardiac arrest, ventricular arrhythmia, heart failure, rhabdomyolysis, acute renal failure or death (corresponds to ’admission with ≥1 event' under the composite outcome in table 3). Occurrences of the composite outcome do not equal the sum of other events, because some admissions included more than one type of event but this only counted once towards the composite outcome.

  • ARDS, adult respiratory distress syndrome.