A New Approach to Evaluating the Effects of Drug Treatment in Intermittent Claudication

Summary

Recently published European guidelines recommend that trials of drugs used for the management of intermittent claudication are carried out in a patient population selected according to strict inclusion and exclusion criteria, such as initial walking distance and the need to exclude patients with unstable claudication. However, it is questionable whether patients selected on this basis are representative of the general population with claudication and, therefore, whether findings of studies conducted in accordance with these guidelines can be extrapolated to the average patient who consults a physician.

In a attempt to clarify these uncertainties, we have conducted a meta-analysis of 5 clinical studies of naftidrofuryl in which a significant minority of patients were recruited who did not comply with the strict inclusion and exclusion criteria of the European guidelines. We also used a new measurement of efficacy, the time to first stable improvement, which we believe ensures that any improvements in walking distance, the gold standard for evaluating treatment effects, are clinically relevant. The use of two relevant measurements of success confirmed a positive drug effect, irrespective of whether all patients with intermittent claudication or only those with stable disease were included.

We believe that, although guidelines are necessary for the scientific evaluation of new active substances, it is important to determine whether findings can be extrapolated to the wider population with claudication.