Relationship Between Bioimpedance Vector Displacement and Renal Function After a Marathon in Non-elite Runners.

Lexa Nescolarde,Antoni Bayes-Genis,Paco Bogónez-Franco,José Hernández-Hermoso,Emma Roca,Jordi Ara

doi:10.3389/fphys.2020.00352

Abstract

Purpose: This study investigates the relationship between whole-body bioimpedance vector displacement, using bioelectrical impedance vector analysis (BIVA), and renal function through serum biomarkers [creatinine, urea, sodium, C-reactive protein (CRP), and creatine kinase] and urine biomarkers after a marathon.Methods: Bioimpedance measurements were taken among 19 non-elite runners at 24 h pre-race, immediately post-race, and at 48 h post-race. The bioimpedance measurements were analyzed by BIVA using the Hotelling’s T2 test. The runners were divided according to a cutoff of serum creatinine level immediately post-race in G1 (<1.2 mg/dl of serum creatinine level) and G2 (≥1.2 mg/dl of serum creatinine level). The increase of the serum creatinine levels in 83% of G2 runners was related to acute kidney injury (AKI) stage 1.Results: Neither G1 nor G2 showed a creatinine clearance rate (CCr) lower than 60 ml/min. G2 showed a significant increase in CRP values at 48 h post-race vs baseline compared to G1 (P < 0.05), with over 5 mg/L (6.8–15.2) in 92% of the runners, and in CK values with over 215 U/L (282–1,882) at 48 h post-race in 100% of the runners. By BIVA, the 95% confidence ellipses of G2 showed shorter bioimpedance vectors than G1, with a noticeable minor Xc/H (P < 0.01), indicating an expansion on extracellular water and inflammation. The runners with 48 h post-race Xc/H values ≤30.5 Ω, with a decrease from −3 to −12% with respect to the Xc/H value at 24 h pre-race, indicated AKI stage 1 with 85.7% sensitivity and 91.7% specificity, with a direct correlation between AKI stage 1 with greater CRP values at 48 h post-race and bioimpedance vector displacement, but not with CK values at 48 h post-race.Conclusion: Through this data collection, it was evidenced that a transient reduction in renal function is more related to inflammatory factors than muscle damage. The BIVA method along with serum biomarkers could be used to follow up the kidney function in runners.

Highlights

The usual practice of sport has a direct positive impact on physical health in general (Hawley et al, 2014)
This study investigates, for the first time, the relationship between whole-body bioimpedance vector displacement by bioelectrical impedance vector analysis (BIVA), using a 50-kHz phase-sensitive bioimpedance analyzer, with renal function through serum and urine biomarkers in non-elite marathon runners after a marathon
The transient reduction in renal filtration function is more related to the inflammatory factors rather than to muscle damage

Summary

Introduction

The usual practice of sport has a direct positive impact on physical health in general (Hawley et al, 2014). Stage 1 AKI was defined as a 1.5-fold to twofold increase or 0.3 mg/dl increase in serum creatinine from day 0 to peak creatinine value on either day 1 or day 2 (McCullough et al, 2011; Kellum et al, 2013). Other authors relate an acute kidney injury after contrast medium (CI-AKI) as an absolute increase ≥0.5 mg/dl over baseline serum creatinine (Maioli et al, 2012). Urea is the principal nitrogen waste product of protein metabolism, and it is eliminated from the body almost exclusively by the kidneys in urine, serum creatinine is the main biomarker to define acute kidney injury (Kellum et al, 2013)

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Discussion

Conclusion