Positive Urine Drug Screens and External Mortality in Teenagers Who Present for Medical Care

Abstract

Objective: To examine whether a positive urine drug of abuse screen in youth who receive medical care is associated with subsequent risk of external mortality (eg, overdose, suicide, homicide, accident). Methods: This was a population-based retrospective cohort study of all Olmsted County (Minnesota) residents who were 13–18 years of age at the time of urine drug screen (UDS) testing (January 1, 1999, to November 28, 2012). Cox regression models were used to examine the relationships between having a positive UDS and external mortality, adjusted for sex, race, age, alcohol exposure, psychiatric diagnoses as defined by the International Classification of Diseases (ICD-9/ICD-10), and medical setting of UDS testing. Separate analyses were done for (1) overall UDS results, (2) tetrahydrocannabinol (THC), and (3) cocaine. Results: Of the 2,772 teenagers included in this study (47.2% male), a total of 26 died of external causes during a median follow-up period of 11.8 years. Testing positive for any illicit substance was not associated with significantly increased risk of external mortality (hazard ratio [HR] = 1.9; 95% CI, 0.9–4.2). Testing positive for cocaine was associated with significantly increased risk of external mortality (HR = 7.0; 95% CI, 1.9–25.0). Testing positive for THC was associated with a marginally significantly increased risk of external mortality (HR = 2.1; 95% CI, 1.0–4.7); however, when cocaine was added as a covariate in the analysis, the relationship between THC-positive UDS and mortality was still elevated but was no longer statistically significant (HR = 1.8; 95% CI, 0.8–4.1). Conclusions: History of cocaine-positive UDS may help identify a population of young people who are at high risk of premature death.