Interventions:
The intervention was described and the comparator was appropriate, as it was the usual practice in the study setting.
Effectiveness/benefits:
The clinical data were from one RCT. The details of this trial, including the sample size calculation, the method of randomisation, and the baseline characteristics, were reported and the validity of the data was generally high, but the number of participants (67) was well below the power calculation (177). The reasons for this low recruitment were not discussed. The follow-up period of 10 months might not have been long enough to capture the full effects of the intervention. QALYs were an appropriate measure of benefit, given the impact of panic disorder on quality of life and they allow comparisons to be made with other disorders.
Costs:
Those costs relevant to the authors' reported perspective appear to have been included. The resource use was reported separately for each intervention and cost item, but the sources for the unit costs were unclear, except for the medications. The price year was reported, which will enable future inflationary exercises. Discounting was not necessary as all the costs were incurred within a year. The authors reported that regression models were used to estimate the mean costs and outcomes, adjusting for differences at baseline and the likelihood that observations would be missing.
Analysis and results:
: An appropriate incremental analysis was performed and allowed an assessment of the cost-effectiveness of the intervention. The uncertainty in out-patient unit costs and the number of specific mental health referrals was investigated in univariate sensitivity analyses. The authors compared their findings with those of other published studies, which had similar incremental cost-effectiveness ratios, and suggested that the lifestyle intervention costs could be reduced by group therapy, but further research was needed. They discussed a number of limitations to their analysis including the sample size and the relatively narrow perspective of the analysis; a broader perspective might have captured indirect costs, such as those of work productivity.
Concluding remarks:
: The methods seem to have been appropriate and the results were relatively well reported. The authors' conclusions appear to be appropriate.