Substance-related problems in patients visiting an urban Canadian emergency department

EM Advances

CJEM 2008;10(3):198-204

Abstract

Résumé

Introduction

In Canada, 47% of men and 24% of women are estimated to be or to have been heavy drinkers (defined as more than 5 drinks on 1 occasion). The prevalence of alcohol dependence is estimated to be 2.6%.1 The annual Canadian economic costs attributed to alcohol and illicit drugs is almost $23 billion. These costs include $5.4 billion for law enforcement, $4.4 billion for health care and $11.8 billion for lost productivity owing to alcohol- or drug-related disability.2 In 1995, alcohol was responsible for 6500 deaths and 172 000 years of potential life lost.3 Alcohol and illicit drug use often result in problems that require medical attention. Emergency physicians and nurses have long recognized that a considerable minority of emergency department (ED) patients have substance use problems. These problems may be associated with poverty, homelessness, legal troubles, psychiatric illness and medical problems.4 Numerous studies document a prevalence of substance abuse or dependence in approximately 20% of ED patients.5-12 Substance abuse has been associated with up to 50% of all injuries.13-17 Although the bulk of these data is from the United States, the Canadian situation is likely similar.18

In this study, we sought to determine the prevalence and characteristics of substance-related medical problems in patients visiting an urban, Canadian tertiary care adult hospital ED. We compared ED length of stay, admission rates and 1-year revisit rates between patients with and without substance problems.

Methods

This study was conducted in the ED of Vancouver General Hospital, a tertiary care, adult, urban, level 1 trauma centre with an annual ED census of approximately 55 000 patients. Our institutional clinical ethics review board approved the study.

All study data were extracted by 2 research assistants (RAs) under the direction of the principal investigator and an experienced research nurse. Explicit criteria were developed a priori to define what represented a substance-problem patient and whether or not a particular ED visit was substance-related (directly attributable to substance use). To do this, a convenience sample of 1897 ED charts were reviewed and the RAs recorded common presentation scenarios. Our team (RAs and investigators) held a series of meetings to categorize these scenarios and to develop face valid explicit criteria for the various categories. These criteria are presented in Appendix 1. Once the criteria were agreed upon, we began a 6-week prospective chart review of all ED visits.

During the 6-week period from June 25, 2002, to Aug. 6, 2002, charts of all patients visiting our ED were reviewed. RAs reviewed all available ED documentation, including emergency medical service (EMS) patient care records, nursing notes, social worker consultations, emergency physician notes and consultant notes. The inpatient records of admitted patients were not reviewed. Reviewers used the criteria developed previously (Appendix 1) to answer 2 questions:

1. Does the patient have documentation of a substance abuse problem?
2. Is this visit related to the patient's use of alcohol or drugs?

For any positive response, the involved substance(s) were recorded. Additional information, including the date and time of admission and discharge, final disposition, age and sex, were captured from an electronic ED database.

Throughout the study period, the principal investigator and reviewers met regularly to discuss ambiguous cases. For patients with multiple visits during the study period, each visit was considered a discrete event based on the documentation available for that visit only. The exception to this was for patients who returned for a scheduled revisit (e.g., to receive antibiotics for cellulitis) and for whom the subsequent visits were classified based on the initial visit.

During the 6-week data collection period, we measured interrater agreement by having both RAs independently review a sample of 300 charts. Cases of disagreement were resolved by consensus between the RAs and the principal investigator.

Finally, the frequency of patient revisits was determined using the electronic ED database for the 1-year period from Sept. 1, 2002, until Aug. 31, 2003. The 3-week interval between the end of chart reviews on Aug. 6 and the beginning of the revisit period on Sept. 1 was chosen to increase the likelihood that revisits were for a new problem not directly related to the index presentation.

Statistics

Statistical analyses were performed using Stata (Version 5.0, Mac, StataCorp, College Station, Texas). Binomial confidence intervals (CIs) were calculated for noteworthy proportions. Secondary comparisons between proportions were done using a 2-tailed Pearson χ2 test. Means of normally distributed continuous variables were compared using 2-tailed, 2-sample t tests with adjustment for unequal variance as appropriate. The Mann-Whitney test was used to compare the means of the nonparametric variables. A p value of 0.05 or less was considered statistically significant for the secondary statistical comparisons. No adjustment for multiple comparisons was performed.

Results

During the 6-week study period there were 6064 visits by 5194 patients. We were able to capture 6026 visits (99.4%) by 5188 (99.9%) patients. Of these, 38 visits were excluded because we were unable to locate the records. Of the 5188 patients reviewed, 600 (11.6%, 95% CI 10.7%-12.5%) had at least 1 visit with documentation of a substance problem. Most patients with substance problems were male (414/600, 69.0%). The most commonly abused substance was alcohol. Patients with substance-related visits were younger than those without (39.2 yr v. 48.3 yr, p < 0.001). Table 1 provides the age and sex breakdown of patients with various types of substance problems.

Five hundred and twenty-one visits (8.6%, 95% CI 7.9%-9.4%) made by 469 patients were related to a substance-related medical problem. The mean and median time spent in the ED before discharge was 322 and 232 minutes, respectively (IQR [interquartile range] 267 min), for substance-related visits, compared with 252 and 164 minutes, respectively (IQR 167 min), for other visits (p < 0.001). For admitted patients, there was no significant difference between the time spent in the ED before transfer to the wards during a substance-related visit (mean 927 min, median 597.5 min, IQR 910 min) when compared with a nonsubstance-related visit (mean 1061 min, median 656 min, IQR 1102.5 min; p = 0.087).

Visits with a documented substance problem resulted in admission to hospital more often than other visits. Of 674 visits with a documented substance problem, 177 (26.3%) resulted in admission to hospital, compared with 926 admissions during 5352 visits (17.3%) for patients without documentation of a substance problem (p < 0.001). Patients with substance problems were also more likely to leave against medical advice or without being seen, and men with substance problems were more likely to leave in police custody. Patients were discharged to a withdrawal management ("detox") unit in only 1% (5/521) of visits with a recorded substance problem. Table 2 shows combined male and female disposition data. These results were similar when stratified by sex, except that no females were discharged into police custody.

Patients with substance-related problems had more revisits during 1 year follow-up than those without. Of the 600 patients with documented substance problems, 161 (26.8%) had at least 1 revisit, compared with 975 of 4588 patients without substance problems (21.3%, p = 0.002). Patients with substance problems averaged 0.78 revisits per patient, compared with 0.47 revisits for patients without substance problems (p < 0.001). Additional revisit data are shown in Table 1.

Interrater agreement between reviewers with regard to patient categorization was excellent. For 297 of 300 charts (99%), there was complete agreement between the 2 reviewers with regard to whether or not the patient had a substance-related visit and whether or not they had documentation of a substance problem.

Discussion

We found that substance problems are a frequent cause of ED visits and hospital admissions in an urban Canadian hospital. Although we found documentation of substance problems in approximately 18% of males and 8% of females visiting our ED, our numbers are lower than in some other ED-based studies. Whiteman and colleagues19 screened 2432 adult patients visiting an inner city US hospital and found evidence of alcohol problems in 24%. In other US studies involving direct patient interviews, researchers found evidence of alcohol problems in 54% of drinking college students presenting to ED,7 in 43% of young adult drinkers8 and in 21% of all adult ED patients.9 In a British study, Thom and coworkers10 found that 37% of young adults attending the accident and emergency department were drinking harmfully, and 15% considered their visit to be alcohol related. Cherpitel and colleagues18 interviewed patients in 2 Canadian EDs and found that 22% of injured patients and 11% of noninjured patients in 2 Canadian EDs reported using alcohol in the 6 hours before their visit, and that 3% of injured patients and 2% of noninjured patients reported drug use in the previous 6 hours.

We believe that our lower numbers are largely explained by the fact that we relied on chart review rather than direct patient interviews to identify patients with substance problems. Our results are similar to other chart review studies that found documentation of alcohol problems in 13% of all ED visits by college students20 and documentation of any "alcohol or drug use" in 15% of ED visits by adolescents.21

Future directions

Our findings suggest that substance problems exist in a significant proportion of ED patients and thus support the need for ED-based services targeting such patients. The potential societal benefit of ED-based programs of screening and intervention for substance problems is highlighted by the fact that approximately 13% of Canadians visited an ED in 2003.22 Inpatient counselling services, although beneficial, will miss the majority of ED patients with substance problems. In our study, 67% of ED patients with substance-related visits were discharged home, 25% were admitted to hospital and only 1% were discharged to a withdrawal management unit. There is growing evidence that even brief interventions that could be applied in the ED are beneficial for patients with substance problems.23 Several recent studies have investigated programs of screening and brief intervention for ED patients with substance problems. These programs had promising results, including fewer hospital admissions and fewer drinking and driving episodes.21-27 Unfortunately, no trial has yet evaluated interventions provided by ED clinical staff. This has created a barrier to their translation into clinical practice. Furthermore, there have been no Canadian trials of brief interventions for ED patients.

Limitations

As with any chart review, our study is limited by the quality of the information that is recorded in the medical record. During the time of this study our ED did not have universal screening for substance problems, and it is likely that many substance problems went undetected. It is also probable that some patients were recognized as having substance problems but that these problems were not recorded in the medical record either because they were not considered relevant to the presenting complaint or because they were not perceived as being particularly harmful. Another limitation is that our study was restricted to the summer months and is therefore unable to detect any seasonal variation in substance use and related problems.

Our findings are strengthened by the fact that we developed explicit criteria defining a substance problem and substance-related visit. These criteria were deemed to have face validity by our team of emergency medicine and addictions experts. Nevertheless, some of our criteria may appear to be overinclusive. For example, not all patients who have an injury after drinking alcohol are problem drinkers. However, there is evidence that most patients who present to the ED after drinking alcohol do indeed have an alcohol-use problem. For example, Savola and coworkers24 found that the vast majority (84%) of injured patients with detectable serum alcohol levels had substantially elevated concentrations (≥ 22 mmol/L).

Conclusion

We found that a significant proportion of patients visiting a tertiary ED had documented evidence of a substance problem. Patients with substance problems were younger but spent longer in the ED before discharge, were more likely to be admitted to hospital and were more likely to revisit the ED the following year. Our findings suggest that programs targeting ED patients with substance problems could benefit a substantial portion of the ED patient population.

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