Performance characteristics of the Posttraumatic Stress Disorder Checklist in retired firefighters exposed to the World Trade Center disaster

Objective: To evaluate the performance of the self-administered Posttraumatic Stress Disorder Checklist (PCL) in retired Fire Department, City of New York (FDNY) firefighters as a screening tool in relation to the interviewer-administered Diagnostic Interview Schedule (DIS), a diagnostic tool that assesses full PTSD criteria.

Methods: From 12/2005 to 7/2007, FDNY enrolled retired firefighters who were exposed to the World Trade Center (WTC) disaster in its WTC Medical Monitoring and Treatment Program, previously limited to its active workforce. All retirees completed the PCL and the DIS on the same day. Sensitivity, specificity, receiver operating characteristic (ROC) curves, and Youden's index were used to assess properties of the PCL and to identify an optimum cutoff score. Bivariate and multivariate logistic regression analyses were used.

Results: 6% of 1,915 retired male firefighters were diagnosed with PTSD using the DIS. Depending on the PCL scoring method, the prevalence of elevated risk varied from 16% to 22%. Youden's index identified an optimal cutoff score of 39, in contrast with the frequently recommended cutoff of 44. At 39, PCL sensitivity was 0.85, specificity was 0.82, and the area under the ROC curve was 0.91 relative to DIS PTSD diagnosis.

Conclusions: PTSD is associated with significant morbidity. Treatment modalities vary in cost, efficacy and geographic availability. Therefore, it is important to identify individuals at elevated risk using a simple screening tool. This study is one of only a few, and the first in firefighters, to validate the PCL and determine the optimal cutoff score for this population.