Title: Incidence and outcomes of positive urine drug screen in neurocritical care
Authors: Siavash Panahi, Morgan Daniel, Sam Pournezhad, Katleen Chester
Objective: To assess the incidence and clinical outcomes associated with positive UDS results in patients admitted to the neurocritical care unit (NCCU) of a large, urban, academic medical center.
Self Assessment Question: Is the incidence higher or lower than Medical and Surgical ICU?
Background: Substance use disorder (SUD) remains a major public health concern, affecting approximately 20.4 million individuals in the United States. Various substances, including amphetamines (AMP), fentanyl, opiates, cannabinoids (CBD), cocaine, benzodiazepines (BZDs), barbiturates (BAR), and methadone, exert significant effects on the central nervous system. Urine drug screening (UDS) is commonly used in hospitalized patients to detect these substances or their metabolites. While previous studies have evaluated the impact of positive UDS results in medical and surgical intensive care units (ICUs), limited data exist on the influence of positive UDS findings on neurocritical care unit (NCCU) admissions and patient outcomes. The objective of this study is to assess the incidence and clinical outcomes associated with positive UDS results in patients admitted to the NCCU of a large, urban, academic medical center.
Methods: This retrospective review analyzed NCCU admissions at Grady Memorial Hospital from January 2016 to December 2023. The study included all NCCU patients with at least one UDS result, considering only the first UDS per encounter. Patients were excluded if they received any dose of the listed substances after hospital arrival and before UDS sample collection. The primary outcome was the incidence of positive UDS results. Secondary outcomes included hospital length of stay (LOS), ICU LOS, the incidence of positive results for each substance, prevalence of single-substance versus multi-substance use, opioid exposure via morphine milligram equivalents (MME), and mortality rates.
Results: Among the 2,430 NCCU encounters, 46% (n = 1,116) were associated with a positive UDS result. Of these, 70% (n = 779) were positive for a single substance, while 30% (n = 367) indicated multi-substance use. The most frequently detected substances were BZDs (19.5%), fentanyl (13.5%), and cannabinoids (11.9%). Patients with positive UDS results had a significantly higher median hospital LOS (7 days [IQR: 3–16] vs. 6 days [IQR: 3–14], p = 0.003), while ICU LOS was slightly longer but not statistically significant (3.3 days [IQR: 1.6–7.9] vs. 2.9 days [IQR: 1.5–6.9], p = 0.09). Patients with positive UDS results demonstrated significantly higher opioid exposure during admission, with median MME levels of 378.75 (IQR: 59–2250) compared to 120.75 (IQR: 18–1098) in UDS-negative patients (p < 0.001). Substances associated with significantly higher MME included amphetamines, barbiturates, BZDs, cannabinoids, methadone, and opiates (p < 0.05 for all), whereas cocaine and fentanyl did not show statistically significant differences. Overall mortality did not significantly differ between UDS-positive and UDS-negative patients (21.2% vs. 19.9%, p = 0.46). However, subgroup analysis revealed significantly higher mortality rates among patients testing positive for cocaine (26.9%, p = 0.044) and BZDs (28.6%, p = 0.00013), while other substances did not show statistically significant differences.
Conclusion: This study highlights a high prevalence of substance use among NCCU patients, with BZDs, fentanyl, and CBD being the most frequently detected substances. Positive UDS results were associated with prolonged hospital LOS and higher opioid exposure. Additionally, patients testing positive for cocaine and BZDs exhibited significantly higher mortality rates, underscoring the need for targeted interventions in this population. These findings emphasize the impact of substance use on neurocritical care outcomes and the importance of optimizing management strategies for affected patient.
