Evaluation of creatinine, cystatin C and eGFR by different equations in professional cyclists during the Giro d'Italia 3-weeks stage race.
Abstract In this study, creatinine-based equations to evaluate glomerular filtration rate (eGFR) were proposed to more accurately assess kidney function, and cystatin C, a parameter not dependent on muscular mass, was introduced to improve GFR calculation in professional cyclists during a long-lasting race. Nine cyclists participating in the 2011 Giro d'Italia were recruited. Blood and anthropometrical data were collected the day before (T-1) the race, on the 12th day (T 12) and on the 22nd day (T 22) of the race. Haemoglobin and haematocrit were registered. Haemodilution was observed at T 12, whilst stabilization was evident at T 22. Creatinine, cystatin C concentrations and eGFR values were not modified during the observed period; only GFR evaluated with the Cockcroft-Gault (CG) formula and expressed as ml/min/1.73 m(2) significantly decreased (p < 0.05) at T 22 in comparison with T-1, probably as a consequence of weight decrease. Cystatin C levels were in the reference range, while creatinine concentrations were lower. The lowest eGFR values were observed with CG normalized and the Modification of Diet in Renal Disease (MDRD) formulas. A good correlation was observed between the MDRD and the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equations and between CG normalized and both CKD-EPI and MDRD formulas. The worst correlation was registered between CKD-EPI creatinine and cystatin C and all the other equations. In conclusion, adaptive mechanisms of renal function allow athletes to maintain stable creatinine, cystatin C and eGFR values during a long-lasting race. The use of GFR equations to evaluate general health status of sportsmen should be recommended with caution, considering also weight modification during competition.
I.R.C.C.S. Istituto Ortopedico Galeazzi, Milano, Italy. alessandra.colombini@grupposandonato.it
Alessandra
A
Colombini
Roberto
R
Corsetti
Rosa
R
Graziani
Giovanni
G
Lombardi
Patrizia
P
Lanteri
Giuseppe
G
Banfi
D001642:Bicycling; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005919:Glomerular Filtration Rate; D006801:Humans; D007558:Italy
D055316:Cystatin C; D003404:Creatinine