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Word of the Day

Single question can rule out drug abuse in high prevalence population

Clinical Question:
Can a single question correctly identify patients who abuse drugs?

Bottom Line:
A single question -- "How many times in the past year have you used an illegal drug or used a prescripton medication for nonmedical reasons?" -- can effectively rule out drug abuse in a high prevalence population. (LOE = 2b)

Smith PC, Schmidt SM, Allensworth-Davies D, Saitz R. A single-question screening test for drug use in primary care. Arch Intern Med 2010; 170(13):1155-1160.  [PMID:20625025]

Study Design:
Cohort (prospective)


Outpatient (primary care)

This study was conducted on patients in a general internal medicine clinic in inner-city Boston. Slightly more than half the participants were women, with a mean age of 49.0 years. More than one third (34.6%) reported currently using drugs, and 47% reported a drug use disorder in their lifetime. A random sample of patients was approached to participate in the study; approximately half refused. Excluding non-English-speaking patients and people who were accompanying a patient at the clinic (not a patient themselves) left 394 eligible patients. Of these, 73% completed the interview and only 55% of eligible patients also had testing for drugs of abuse. In other words, the study subjects were highly selected from an English-speaking population with a high rate of drug use. All were asked a single question: "How many times in the past year have you used an illegal drug or used a prescripton medication for nonmedical reasons?" A response of 1 or more was considered positive for drug use. The reference standard for defining drug use was a computer version of the Composite International Diagnostic Interview, which yields a diagnosis of drug abuse or dependence. Patients who consented also had oral fluid testing for common drugs of abuse. As compared with the diagnostic interview, the single screening question was 100% sensitive (95% CI, 90.6%-100%) and 73.5% specific (67.7%-78.6%). As compared with either self-reported current (within the past 12 months) use or a positive oral fluid test result it was less sensitive (80%), but more specific (94%). In other words, in a high prevalence group, the single question was fairly effective at ruling out drug use (sensitivity = 80% -100%), as well as ruling in drug ues (specificity = 74%-94%).


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