The conclusion by Kitchell was that EDTA was not useful in treating heart disease. 153 patients were randomized to receive 20 EDTA infusions over 5 to 9 weeks using the protocol established by Clarke et al. The study used pain free walking distance and maximum walking distance as markers of improvement. It was determined there no difference between the placebo and treatment groups. They treated 1974 patients with EDTA who had known heart or peripheral vascular disease.
Proponents cite mainly the case report studies as ample proof that chelation therapy works.
Critics also cite that the sample sizes used in the above studies are too small and that the efficacy of chelation therapy is judged based on qualitative instead of quantitative data.