The Addiction Behaviors Checklist: Validation of a New ... - Westat

346 Wu et al.Vol. 32 No. 4 October 2006Table 1Correlation Between ABC Individual Itemsand Concurrent Global Clinical Judgmentat Approximately 4 MonthsAfter Start of Study (n ¼ 101)ABC ItemPearson Correlation Coefficient1 0.182 0.30 a3 0.54 a4 0.44 a5 0.64 a6 0.31 a7 0.0689 0.0210 0.0711 0.52 a12 0.25 b13 0.35 a14 0.25 b15 0.54 a16 0.21 b17 0.25 b18 0.51 a19 0.58 a20 0.04a P < 0.01.b P < 0.05.of patients’ opioid use patterns. As noted, Items2e6 and 11e19 displayed significant correlationswith the interviewer’s global clinical judgment.It should be briefly noted that Table 1does not include information on Variable 8,‘‘patient bought meds on the street,’’ as thisitem was not endorsed across all subjects duringthis initial period of follow-up visits. Over theyear follow-up in general, this item shows highlyinfrequent endorsement (see Discussion).Concurrent ValiditydGlobal Clinical Judgment.Using the provider’s global clinical judgmentas a criterion variable to operationalize appropriatemedication use, initial t-test resultsindicated that the mean ABC scores can significantlydistinguish between patients whodisplay appropriate use of opioid medicationsand patients who display inappropriate use ofopioid medications. Mean ABC scores werehigher for inappropriate users (mean ¼ 5.31,SD ¼ 2.96) than appropriate users (mean ¼ 1.00,SD ¼ 1.27, t(16) ¼ 5.75, P < 0.001).Concurrent ValiditydPDUQ. Correlations weredetermined between mean ABC scores andPDUQ total scores. Mean ABC scores are theaverage ABC score across the initial 4e5months. The Pearson correlation coefficientbetween mean ABC scores and the PDUQ totalscore at this time point was 0.40 (P < 0.01).Sensitivity, Specificity, and Determinationof Cut-Off ScoreUsing the global clinical judgment as the criterionmeasure for inappropriate opioid use,measurements of sensitivity and specificitywere determined comparing the cross-tabulationmeasurements of ABC total score vs. globaljudgment rating. Fig. 1 shows a graphical representationof sensitivity [true positives/(true positivesþ false negatives)] and specificity [truenegatives/(true negatives þ false positives)]measurements for different ABC total scores usingglobal clinical judgment as the criterionmeasurement of inappropriate opioid use. Becauseof a relatively small number of endorsedopioid misuse behaviors at any specific visit,ABC monthly data were combined across allvisits (n ¼ 998) in order to maximize calculationof sensitivity and specificity. These results indicatethat a cut-off score of 3 or greater on theABC shows optimal sensitivity and specificity indetermining whether a patient is displaying inappropriateopioid use. To evaluate the impactof combining data, calculations of sensitivityand specificity at the initial visit time pointwere also performed and reproduced the samefindings of optimal sensitivity/specificity ata cut-off score of 3 or greater (e.g., using ABCdata from initial visit only, sensitivity ¼ 87.50%and specificity ¼ 86.14%).To further evaluate the utility of this cut-offscore, t-tests were performed comparingPercent120100806040200SensitivitySpecificity0 1 2 3 4 5 6 7 8 9ABC Cutoff ScoreFig. 1. Sensitivity vs. specificity based on varyingABC total score. Criterion variable ¼ Interviewer’sGlobal Judgment (n ¼ 998). ABC data collectedacross all visits.