Are subjects in treatment trials of panic disorder representative of patients in routine clinical practice? Results from a national sample.

BACKGROUND

Research on the generalizability of clinical trials in panic disorder is limited. The present study sought to quantify the generalizability of clinical trials' results of individuals with DSM-IV panic disorder (PD) to a large community sample.

METHODS

Data were derived from the National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a large national representative sample of 43,093 adults of the United States population. We applied a standard set of eligibility criteria representative of PD clinical trials to all adults with past 12 months PD (n=907), and then to a subgroup of participants seeking treatment (n=105). Our aim was to determine the proportion of participants with PD who would have been excluded by typical eligibility criteria.

RESULTS

We found that more than 8 out of ten participants (80.52%; 95% CI=77.13-83.52%) with PD were excluded by at least one criterion. In the subgroup of participants who sought treatment, the exclusion rate by at least one criterion was higher (92.40%; 95% CI=84.60-96.42%). For the full sample and the treatment-seeking subsample, having currently a depression and a diagnosis of alcohol or drug abuse/dependence were the criteria excluding the highest percentage of participants. Having a lifetime history of bipolar disorder and a current significant medical condition also excluded a substantial proportion of individuals in both samples. Exclusion rates were similar when considering panic disorder with and without agoraphobia.

CONCLUSIONS

Clinical trials, that exclude a majority of adults with panic disorder, should carefully consider the impact of eligibility criteria on the generalizability of their results. As required by CONSORT guidelines, reporting exclusion rate estimate and reasons of eligibility should be mandatory in both clinical trials and meta-analyses.