Erythropoietin doping in cycling: lack of evidence for efficacy and a negative risk-benefit

Abstract

Imagine a medicine that is expected to have very limited effects based upon knowledge of its pharmacology and (patho)physiology and that is studied in the wrong population, with low-quality studies that use a surrogate end-point that relates to the clinical end-point in a partial manner at most. Such a medicine would surely not be recommended. The use of recombinant human erythropoietin (rHuEPO) to enhance performance in cycling is very common. A qualitative systematic review of the available literature was performed to examine the evidence for the ergogenic properties of this drug, which is normally used to treat anaemia in chronic renal failure patients. The results of this literature search show that there is no scientific basis from which to conclude that rHuEPO has performance-enhancing properties in elite cyclists. The reported studies have many shortcomings regarding translation of the results to professional cycling endurance performance. Additionally, the possibly harmful side-effects have not been adequately researched for this population but appear to be worrying, at least. The use of rHuEPO in cycling is rife but scientifically unsupported by evidence, and its use in sports is medical malpractice. What its use would have been, if the involved team physicians had been trained in clinical pharmacology and had investigated this properly, remains a matter of speculation. A single well-controlled trial in athletes in real-life circumstances would give a better indication of the real advantages and risk factors of rHuEPO use, but it would be an oversimplification to suggest that this would eradicate its use.

Figure 1

Maximal oxygen uptake () before () and after (▴) treatment with rHuEPO in the different studies per treated group (bars representing SD). N is the number of subjects in each group, with an asterisk indicating that the article reported values only in litres per minute, which has been converted to millilitres per kilogram per minute by dividing this value by mean weight of the group for comparison purposes (no SD is given for these studies because of this conversion). Studies above the horizontal red dotted line were performed using subjects classified as untrained, while below the horizontal line the subjects were classified as trained cyclists. Vertical dashed lines represent minimal values of for different classifications of cyclists as suggested by Jeukendrup et al. (brown dashed line, trained; red dashed line, well trained; green dashed line, elite; and yellow dashed line, world class). , ; ▴, ; , trained; , well-trained; , elite; and , world class