“…Studies varied in the response criteria used and the treatments given to patients. However, based on the quantitative associations with response, the general consensus followed that 'responders' had lower mean or median serum EPO levels than 'non-responders'; in 10 studies [26,30,33,36,40,48,50,53,55,59], this relationship was statistically significant while in four studies, it was not statistically significant [28,29,31,45]. The studies where no statistical significance was reported tended to be small (n ≤ 60), single-arm studies [28,29,31,45].…”