The prevalence of alcohol and illicit drug use among injured patients presenting to the emergency department of a national hospital in Tanzania: a prospective cohort study

This is a prospective descriptive cohort study of a consecutive sample of 143 patients aged 18 years and above presenting to the ED-MHH, Dar es Salaam, Tanzania within 12 h of sustaining an injury between 17th October 2015 and 4th November 2015.

This study was conducted at the Emergency Department of Muhimbili National Hospital (ED-MNH). MNH is the national hospital of Tanzania. It is located in Ilala district, Dar es Salaam, Tanzania. MNH has a capacity of 1500 beds. MNH is the highest level of medical care available in the government system in Tanzania, and thus severely injured patients from across the country are referred to MNH. When arriving at MNH, these patients are first evaluated in the ED-MNH. The ED-MNH is open 24 h every day and sees an average of 60,000 patients per year, including approximately 1500 trauma patients per month. It has 3 adult resuscitation rooms and one paediatric resuscitation room. The ED was built in 2009 and opened to patients in January 2010; it is the only recognized public ED in Tanzania. The staff of the ED-MNH is composed of emergency medicine trained faculty, residents, registrars, interns, and nurses. It is a teaching department with a formal residency program which was started in 2010 [15]. Drug and alcohol testing is currently not routinely available at government hospitals in Tanzania. This testing is only performed in special toxicological or suspicious legal cases by the chief chemist of the Government. Our study population included all injured patients aged 18 years and above who arrived at the ED-MNH within 12 h of their injury.

Patient testing and enrollment was completed by the principal investigator and a trained research assistant. All patients arriving at the ED-MNH were screened for eligibility. For patients who met inclusion criteria, we obtained written informed consent. This consent was obtained from the patient if they had capacity, or from the appropriate proxy/relative if the patient had altered mental status. A structured data collection form was used to record age, sex, location of the injury, mechanism of the injury, severity of the injury, patient and relative report of alcohol and illicit drug use, and nurse, and physician presumption of alcohol and drug use.

Blood alcohol concentration was measured by using a Breathalyzer (BACtrack Select S80 Breathalyzer) for those able to properly use the breathalyser. For patients unable to properly use the breathalyser, saliva swab sticks (Instant Alcohol Saliva Test Strips/W53-S) were used to measure the level of alcohol. TheRapidCHECK® 5 Multi-Drug Panel Test, was used to identify illicit drugs using urine samples. It screened for the presence of opioids, cocaine, marijuana, amphetamines, and benzodiazepines.

The primary outcomes were: 1) the prevalence of injured patients with a positive test for alcohol/ illicit drugs at the time of presentation to the ED-MNH; 2) the characteristics of the various substances of abuse among injured patients with a positive test for alcohol and/or illicit drug use at the time of presentation to the ED-MNH; 3) the comparison of patient report, relative report and healthcare provider suspicion of alcohol and/or illicit drug use with the results of objective testing for alcohol and illicit drug use among injured patients presenting to the ED-MNH.

The secondary outcomes were 24-h and 30-day morbidity and mortality rates of injured patients with a positive test for alcohol and/or illicit drugs presenting to the ED-MNH.

All patients were followed up for 30 days and admission to the hospital, need for surgery, 24-h mortality, 30-day mortality, and 30-day return to baseline were recorded.

Data was collected on hand-written data collection forms and then entered into Microsoft Excel (Microsoft Corporation, Redmond, WA) and analysed with Microsoft Excel. Data was summarized in tables using descriptive statistics, percentages, inter quartile ranges, sensitivity and specificity, positive and negative predictive value, relative risk, and 95% confidence intervals were used as appropriate.

During the study period, a total of 1011 adult patients were attended at the ED-MNH, of which 202 had trauma related complaints. Out of 202 patients with trauma, 143 (70.8%) met the inclusion criteria for the study (Fig. 1). All 143 eligible patients were enrolled. 86.0% (n = 123) of patients were male, and their median age was 30 years (IQR 23–36). All 143 patients enrolled were tested for alcohol. Because we were unable to obtain urine from 21 patients during their time in the ED, we tested only 122/143 (85.3%) patients for illicit drugs. 121 (84.6%) of patients were injured on the road, followed by 14 (9.8%) at home, and other locations (5.6%) as shown in Table 1. 80.4% (n = 115) of patients were referred from peripheral health centers, 10.4% (n = 15) were self-referred, and 9.1% (n = 13) were brought by the police (Table 1).

67 (46.9, 95% CI: 39.3–54.7%) patients tested positive for alcohol. Among the 122 patients who were tested for illicit drugs, 44 (36.0, 95% CI: 27.2–44.8%) tested positive. Out of the 122 injured patients who were tested for both alcohol and illicit drugs, 29 (23.7, 95% CI: 16.5–32.3%) tested positive for both alcohol and illicit drugs, 46 (37.7, 95% CI: 29.1–46.9%) tested negative for both alcohol and illicit drugs, and 82 (57.3, 95% CI: 49.2 to 69.1%) patients tested positive for either alcohol or illicit drugs. (Table 2)

Among the 67 patients who tested positive for alcohol, 42 (62.7%) had blood alcohol concentrations between 0.01 and 0.04%; 9 (13.4%) had blood alcohol concentrations between 0.05 and 0.09%, and 16 (23.9%) had blood alcohol concentrations greater than 0.1%. Marijuana was the most common illicit drug detected and was found in 24.5% (n = 30) of patients, followed by opioids 11.5% (n = 14), benzodiazepines 9.8% (n = 12), and amphetamines 2.5% (n = 3). Cocaine was not detected in any patient. Among the 122 patients tested for both alcohol and illicit drugs, 29 (23.8%) patients tested positive for more than one substance of abuse. Of those patients, 22 (18.0%) tested positive for two substances, 6 (4.9%) tested positive for three substances, and 1 (0.8%) tested positive for four substances.

Among the 143 enrolled in the study, 33 patients were not able to answer questions because of altered mental status. Among 53 patients with positive alcohol test that could answer the question, 23 (43%) reported the use of alcohol and among the 25 patients with positive illicit drug test that could answer the question, 3 (12%) reported illicit drug use. Among the 61 patients with positive tests for alcohol whose relatives were available for questioning, 34 (56%) of relatives reported that the patient used alcohol prior to the injury and among the 44 patients with positive test for illicit drug use whose relatives were available, 9 (82%) of the relatives reported the patient had used illicit drugs. Thus, when the patient reported that they had used alcohol, the relative risk of a positive test result was 2.4 (95% CI: 1.7 to 3.3). However, when the patient denied alcohol use, the test was positive in 30/83 (36%) cases. Likewise, when the patient reported that they had used illicit drugs, the relative risk of a positive test result was 3.6 (95% CI: 1.4 to 6.0). However, when the patient denied illicit drug use, the test was positive in 22/106 (21%) cases. Similarly, when a relative reported that the patient had used alcohol, the relative risk of a positive test result was 3.2 (95% CI: 2.3 to 4.6). However, when a relative reported no alcohol use, the test was positive in 27/103 (26%) cases. Finally, when a relative reported that the patient had used illicit drugs, the relative risk of a positive test result was 2.6 (95% CI: 1.6 to 3.7). However, when the relative reports no Illicit drug use, the test was positive in 35/111 (32%) cases (Table 3).

Among the 52 patients with positive tests for alcohol, in 43 (83%) patients, the nurse presumed the patient had used alcohol. The sensitivity and specificity for the nurses’ presumption of alcohol use as a predictor of the test result were 83% (95%CI: 70 to 92%) and 80% (95%CI: 71 to 88%), respectively. Among the 22 patients with positive illicit drug tests, in 1 (5%) patient, the nurse presumed the patient’s use of illicit drugs. The sensitivity and specificity for the nurses’ presumption of illicit drug use as a predictor of the test result were 5% (95%CI: 0 to 23%) and 94% (95%CI: 87 to 98%), respectively. Among the 124 patients with a positive test for alcohol, physicians presumed alcohol use in 44 (85%) patients. The sensitivity and specificity for the doctors’ presumption of alcohol use as a predictor of the test result were 85% (95%CI: 72 to 93%) and 80% (95%CI: 71 to 88%), respectively. Among the 27 patients with positive test for illicit drug abuse, physicians presumed 2 (7%) of the patients had used illicit drugs. The sensitivity and specificity for physician presumption of illicit drug use as a predictor of the test result were 7% (95%CI: 1 to 24%) and 96% (95%CI: 90 to 99%), respectively.

At 24 h and 30 days, the patients with positive alcohol tests were statistically more likely to have required major surgery than the patients with negative alcohol tests (RR 1.42, 95%CI 1.09 to 1.85); the patients with positive tests for illicit drugs were also statistically more likely to get major surgery than the patients with negative tests for illicit drugs (RR: 1.59, 95% CI: 1.23 to 2.06).

Although the results did not reach statistical significance, patients who tested positive for multiple substances were more likely to get major surgery than the patients who were positive for a single substance ingestion (RR: 1.2; 95% CI: 0.73 to 1.05); patients with positive isolated alcohol test were less likely to get major surgery than the patients who tested positive for only drugs (RR: 0.93, 95% CI: 0.64 to 1.35); the patients with positive test for alcohol were more likely to have a prolonged return to baseline than those who were negative for alcohol (RR: 1.19, 95% CI: 0.88 to 1.60); the patients with positive test for illicit drug were more likely to have a prolonged return to the baseline than those who tested negative for illicit drugs (RR: 1.33, 95% CI: 0.97 to 1.83); the patients with positive tests for multiple substance ingestions were more likely to have a prolonged return to the baseline compared to those who were tested positive for one substances abuse (RR: 1.12; 95% CI: 0.81 to 1.56); the patients with positive test for isolated alcohol use were more likely to have prolonged return to baseline compare to those with isolated illicit drugs use (RR: 1.1, 3, 95% CI: 0.66 to 194); the patients who tested positive for alcohol were more likely to die than those who tested negative for alcohol (RR: 1.70, 95% CI: 0.50 to 5.77); the patients with positive testing for illicit drugs were more likely to die than those who tested negative for illicit drugs (RR: 3.54, 95% CI: 0.67 to 18.5); the patients who tested positive for multiple substances were more likely to die than those with single substances ingestion (RR:1.82, 95% CI: 0.34 to 9.57); the patients with positive testing for isolated alcohol use were less likely to die than those who tested positive for isolated drug use (Additional file 1) (RR: 0.39, 95% CI: 0.02 to 5.91) (Table 4).