Observational Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Nephrol. Nov 6, 2016; 5(6): 524-530
Published online Nov 6, 2016. doi: 10.5527/wjn.v5.i6.524
Factors associating with oxygenation of lower-limb muscle tissue in hemodialysis patients
Haruhisa Miyazawa, Susumu Ookawara, Kiyonori Ito, Katsunori Yanai, Hiroki Ishii, Taisuke Kitano, Mitsutoshi Shindo, Yuichiro Ueda, Yoshio Kaku, Keiji Hirai, Taro Hoshino, Kaoru Tabei, Yoshiyuki Morishita
Haruhisa Miyazawa, Susumu Ookawara, Kiyonori Ito, Katsunori Yanai, Hiroki Ishii, Taisuke Kitano, Mitsutoshi Shindo, Yuichiro Ueda, Yoshio Kaku, Keiji Hirai, Taro Hoshino, Yoshiyuki Morishita, Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, Saitama 330-8503, Japan
Kaoru Tabei, Department of Internal Medicine, Minami-uonuma City Hospital, Niigata 949-6680, Japan
Author contributions: Miyazawa H and Ookawara S contributed to data acquisition, data analysis and interpretation, and writing of article; Miyazawa H, Ookawara S and Ito K contributed to study conception and design; Yanai K, Ishii H, Kitano T, Shindo M, Ueda Y, Kaku Y, Hirai K, Hoshino T, Tabei K and Morishita Y contributed to editing, reviewing and final approval of article.
Institutional review board statement: This study was reviewed and approved by Saitama Medical Center, Jichi Medical University (Saitama, Japan).
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: The authors report no conflicts of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Susumu Ookawara, MD, PhD, Division of Nephrology, First Department of Integrated Medicine, Saitama Medical Center, Jichi Medical University, 1-847 Amanuma-cho, Omiya-ku, Saitama-City, Saitama 330-8503, Japan. ookawaras@.jichi.ac.jp
Telephone: +81-48-6472111 Fax: +81-48-6476831
Received: June 27, 2016
Peer-review started: June 29, 2016
First decision: August 5, 2016
Revised: August 26, 2016
Accepted: September 7, 2016
Article in press: September 8, 2016
Published online: November 6, 2016
Processing time: 129 Days and 5 Hours
Abstract
AIM

To evaluate the lower-limb muscle oxygenation in hemodialysis (HD) patients and identify the factors associating with muscle oxygenation.

METHODS

Sixty-seven HD patients (53 men and 14 women; mean age, 67.1 ± 1.2 years; mean HD duration, 5.6 ± 0.9 years) were recruited. In addition, 15 healthy individuals (nine men and six women; mean age, 38.2 ± 4.6 years) were recruited as the control group. Lower-limb muscle regional saturation of oxygen (rSO2) was monitored on the lateral side of the gastrocnemius muscle before HD using an INVOS 5100C (Covidien Japan, Tokyo, Japan), which utilizes near-infrared spectroscopy. Here, we evaluated the association between lower-limb muscle rSO2 and clinical parameters.

RESULTS

The rSO2 values were significantly lower in patients undergoing HD than in healthy individuals (50.0% ± 1.7% vs 76.8% ± 2.5%, P < 0.001). Lower-limb muscle rSO2 showed significant positive correlations with diastolic blood pressure, blood urea nitrogen concentration, serum creatinine concentration, serum potassium concentration, serum inorganic phosphate concentration, and serum albumin concentration as well as negative correlation with HD duration. We conducted a multiple linear regression analysis using parameters that were significantly correlated with the lower-limb muscle rSO2 in a simple linear regression analysis. Multiple regression analysis demonstrated that lower-limb muscle rSO2 was independently associated with serum inorganic phosphate (standardized coefficient: 0.27) and serum albumin concentrations (standardized coefficient: 0.24). In addition, there were no differences in lower-limb muscle rSO2 between diabetic and non-diabetic HD patients. This study has several limitations. Firstly, its sample size was relatively small. Secondly, we could not evaluate the association between lower-limb muscle rSO2 and calculated nutritional markers, including normalized protein catabolic rate and body mass index, anthropometric measurements representing nutritional status, and the severity of protein-energy wasting. Finally, we did not routinely examine the arterial vascular status of HD patients without symptoms of peripheral artery disease. As such, it is possible that some HD patients with subclinical peripheral artery disease may have been included in this study.

CONCLUSION

In HD patients, the oxygenation of lower-limb muscle tissue was associated with serum inorganic phosphate and albumin concentrations, both of which represent nutritional status.

Keywords: Regional saturation of oxygen; Lower-limb muscle; Sarcopenia; Protein-energy wasting; Nutritional status; Inorganic phosphate; Albumin; Hemodialysis

Core tip: Sarcopenia, defined by reduced muscle mass and peripheral arterial disease, is common in patients undergoing hemodialysis (HD). Therefore, muscle status, including muscle oxygenation, would deteriorate; however, no muscle status evaluation method has been established and remains under debate. Here we investigated the tissue oxygenation of lower-limb muscles using near-infrared spectroscopy in HD patients. Values of regional saturation of oxygen in the lower-limb muscles were significantly lower in HD patients than in healthy controls and independently associated with serum inorganic phosphate and albumin concentrations, both of which represent nutritional status.