Positive urine drug screens not reliable indicator of death by external causes in teens

Examination of positive urine drug screens of teenagers was not a reliable predictor for risk for death by external causes, according to a population-based retrospective cohort study published in the Journal of Clinical Psychiatry.

“Current practices for estimating the risk for mortality in teenage substance users rely heavily on clinical intuition. There is an urgent need for evidence-based methods to stratify the risk of early mortality in youth who are abusing substances, including which specific substances are associated with the greatest risk,” Matej Markota, MD, of the department of psychiatry and psychology at the Mayo Clinic in Rochester, Minnesota, and colleagues wrote.

Markota and colleagues sought to ascertain whether examinations of positive urine-based drug tests for youth who required medical care could be linked with future risk for death by external causes, such as overdose, suicide, homicide or other accidents.

The study drew from an initial cohort of 3,298 residents of Olmsted County, Minnesota, aged 12 to 18 years when submitting to urine drug screen testing between Jan. 1, 1999, and Nov. 28, 2012. A total of 2,772 teenagers (47.2% male) aged 13 to 18 years were included in the final analysis. By the end of the follow-up interval, which was Nov. 15, 2017, or date of death, whichever occurred first, 26 participants had died of external causes.

Markota and colleagues assessed relationships between positive UDS result and external mortality, adjusted for sex, race, age, alcohol exposure, psychiatric diagnoses as defined by ICD-9/ICD-10, as well as setting for drug screening. Analyses were also performed to separate overall UDS results, positive results for tetrahydrocannabinol (THC) and positive results for cocaine.

Results showed no significant overall increased risk for death of external causes in participants testing positive for any of the illicit substances. Positive results for THC were associated with a statistically small, elevated risk of death from external means (HR=2.1; 95% CI, 1.0–4.7), but positive tests for cocaine carried a markedly increased risk for premature death (HR=7.0; 95% CI, 1.9–25.0) compared with those with negative UDS results.

“This population-based study of youth who received drug testing as part of their routine medical care found no statistically significant association between testing positive for any substance and external mortality,” Markota and colleagues wrote. “However, cohort members who tested positive for cocaine had a pronounced increase in risk of premature death.”