For many patients with addiction and other substance problems, the emergency department (ED) is the sole provider of medical care. This study sought to determine the prevalence and characteristics of substance-related medical problems in ED patients, as defined by documentation in the medical record. We also sought to compare the ED resource use (length of ED stay and number of revisits) of patients with and without substance problems.

Trained evaluators using explicit criteria reviewed all ED charts during a 6-week period at a Canadian tertiary care teaching centre. Data was collected on demographics, documentation of problematic substance use and whether the ED visit was due to substance problems. Using a computerized database, we determined how many patients with and without substance problems had 1 or more subsequent ED visits during the 1-year period from Sept. 1, 2002, to Aug. 31, 2003.

Of 6064 visits made by 5194 patients, 6026 visits (99.4%) representing 5188 patients (99.9%) were captured for review. Of those visits, 674 (11.2%, 95% confidence interval [CI] 10.4%–12.0%), made by 600 patients, had documentation of problematic substance use and 521 visits (8.6%, 95% CI 7.9%–9.4%) by 469 patients were caused by substance problems. The mean age of patients with a visit due to a substance problem was 39.2 years, compared with 48.5 years for those with other visits (p < 0.001). The admission rate for substance-related visits was 25.3%, compared with 17.6% for other visits (p < 0.001). For discharged patients, the median length of the ED visit owing to substance-related problems lasted 232 minutes (IQR [interquartile range] 267 min), compared with 164 minutes (IQR 167 min) for other visits (p < 0.001). In 1 year of follow-up, 161 of 600 patients (26.8%) with a substance problem made 466 revisits (mean 0.78 revisits/patient), compared with 975 of 4588 patients (21.3%) without a substance problem who made a total of 2150 revisits (mean 0.47 revisits/patient, p < 0.001).

Substance problems contribute significantly to ED visits, hospital admissions and duration of ED stay at a tertiary centre. It is likely that our methodology underestimates the scope of the problem and that a universal screening program would find a higher prevalence. The magnitude of this problem supports the need for an interdisciplinary identification and intervention program for ED patients with substance-related issues.

Understanding ambulance utilization patterns is essential to assessing prehospital system capacity and preparedness at the national level.

To describe the characteristics of patients transported to US emergency departments (EDs) by ambulance and to determine predictors of ambulance utilization.

Data were obtained from the National Hospital Ambulatory Medical Care Survey using mode of arrival, demographic and visit information, ICD-9-CM E and V-codes, and classified reasons for the visit.

The rates for ED visits of persons conveyed by ambulence were stable between 1997 and 2003, consisting of approximately one in every seven ED visits (14%). In 2003, there were 16.2 million ED visits for which an ambulance was used in the US. However, for patients with mental health visits, nearly one in three ED presentations (31%) arrived by ambulance. Significantly higher rates of ambulance use were associated with: (1) mental health visits; (2) older age; (3) African-Americans; (4) Medicare or self-pay insurance status; (5) urban ED location; (6) US regions outside of the South; (7) presentation between 12 midnight to 0800 hours; (8) injury-related visits; (9) urgent visit status; and/or (10) those resulting in hospital admission. Among mental health patients, older age, self-pay insurance status, urban ED location, regions outside the southern US, and urgent visit classification predicted ambulance use. Ambulance usage within the mental health group was highest for suicide and lowest for mood and anxiety disorder-related visits.

Reliance on ambulance services varies by age, insurance status, geographic factors, time of day, urgency of visit, subsequent admission status, and type of mental health disorder. Even after controlling for many confounding factors, mental health problems remain an important predictor of ambulance use.