Review of mortality and cardiovascular event rates in patients enrolled in clinical trials for claudication therapies

Pharmacological and non-pharmacological interventions to improve function and quality of life in patients with claudication are being evaluated in clinical research trials. An important component of clinical development programs is assessing the safety of the intervention and monitoring for adverse impact of the therapy on research participants. The conduct of both of these safety assessments is facilitated by the ability to estimate the anticipated rates of cardiovascular events and death in the target population. To obtain estimates of these rates, data were abstracted from randomized, double-blind, placebo-controlled trials performed in patients with claudication and designed to show functional improvement, and which have been published since 1990. Patient-year exposures and the number of deaths, serious adverse events and cardiovascular serious adverse events in the placebo arms of these trials were tabulated, and summed event rates calculated. The mortality rate was 1.9 deaths per hundred patient-years (27 deaths observed in 1446 patient-years). The mortality rate in claudication trials is lower than that reported in natural history studies. Cardiovascular serious adverse events in claudication trials were observed at a rate of 8.5 per hundred patient-years (65 events in 762 patient-years). Thus, cardiovascular morbidity and mortality should be expected in clinical trials enrolling claudicants. The current analyses provide benchmark data for ensuring that development programs are large enough to allow meaningful safety conclusions, and to assist in data and safety monitoring of these trials.