Table 2. Crude incidence rate (IR) per 100 person-years, crude hazard ratio (HR), and 95% confidence intervals (CI) for emergency department (ED) encounters, hospital admissions, and potentially avoidable ED encounters, whole cohort and by current depression and recreational drug use status measured at the baseline.
| ED encounters | Hospital admissions | Potentially avoidable ED encounters | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| (N = 2,108) | ||||||||||
| (N = 3,482) | (N = 3,482) | Low-acuity ED encounters a | Repeated ED encounters b | ED encounters without seeking ambulatory care c | ||||||
| IR | Crude HR Ratio | IR | Crude HR Ratio | IR | Crude HR Ratio | IR | Crude HR Ratio | IR | Crude HR Ratio | |
| (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | |
| Cohort | 25.6 | 6.9 | 19.4 | 10.9 | 7.9 | |||||
| (24.5, 26.8) | (6.4, 7.4) | (18.3, 20.6) | (10.2, 11.7) | (7.2, 8.6) | ||||||
| Current depression and recreational drug use | ||||||||||
| Current depression-only | 34.8 | 1.6 | 9.1 | 1.5 | 21.8 | 1.2 | 12.2 | 1.3 | 7.3 | 1.03 |
| (31.8, 38.0) | (1.4, 1.7) | (7.9, 10.4) | (1.3, 1.8) | (19.4, 24.6) | (1.1, 1.4) | (10.5, 14.1) | (1.1, 1.5) | (6.5, 8.2) | (0.8, 1.3) | |
| Recreational drug use-only | 30.0 | 1.3 | 6.0 | 1.0 | 22.8 | 1.3 | 13.2 | 1.4 | 7.5 | 1.5 |
| (26.4, 34.1) | (1.2, 1.5) | (4.8, 7.6) | (0.8, 1.3) | (19.2, 27.0) | (1.1, 1.6) | (10.8, 16.2) | (1.1, 1.8) | (6.3, 9.0) | (1.2, 1.9) | |
| Co-occurring current depressive symptoms and recreational drug use | 51.9 | 2.2 | 13.0 | 2.2 | 25.6 | 1.4 | 16.9 | 1.8 | 10.8 | 1.2 |
| (44.8, 60.1) | (1.9, 2.6) | (10.4, 16.1) | (1.7, 2.7) | (21.1, 31.1) | (1.1, 1.7) | (13.5, 21.1) | (1.4, 2.3) | (8.7, 13.4) | (0.9, 1.7) | |
| Without current depression and recreational drug use (reference) | 21.2 | 1 | 5.9 | 1 | 17.2 | 1 | 9.4 | 1 | 9.2 | 1 |
| (20.0, 22.4) | (5.4, 6.5) | (15.8, 18.6) | (8.5, 10.3) | (6.9, 12.2) | ||||||
IR = Incidence rate
HR = Hazard ratio
CI = Confidence intervals
ED = Emergency department encounters
a Low-acuity ED encounters were identified using level four or five of the five-level Canadian triage and acuity scale (1 = resuscitation, 2 = emergency, 3 = urgent, 4 = semi-urgent, 5 = non-urgent) AND a visit disposition at discharge that indicated the participants were not transferred to inpatient care.
b Repeated ED encounters were defined by discharge date of an emergency department encounter that occurred within 30 days of a previous encounter at the same or a different facility.
c Emergency department encounters without seeking ambulatory care were defined as emergency department encounters without an ambulatory visit to a physician in the 30 days prior to the index encounter