Consistency of the estimated target weights and ECW/TBW using BIA after hemodialysis in patients between standing and lying-down positions

Background

As hemodialysis is administered with the patient lying down, the distribution of body fluid is stable in the lying position, which is why this position is recommended for bioimpedance analysis (BIA). Although the InBody S10 is widely used for hemodialysis patients in the lying position, clinicians must make the measurements in person. In contrast, patients can use the InBody 770 to obtain measurements by themselves in the standing position, which may be more convenient. Therefore, this study compared the measurements of hemodialysis patients’ estimated target weight and ECW/TBW obtained lying down using the S10 to those obtained in the standing position using the 770.

Methods

This study was conducted among maintenance hemodialysis patients at Chuncheon Sacred Heart Hospital in October 2020. Measurements from 56 patients before and after hemodialysis were obtained using the 2 machines. Each (S10 or 770) estimated target weight, both pre- and post-hemodialysis, was considered ideal when the ECW/TBW ratio was 0.380. R² was calculated and the Bland-Altman test was performed.

Results

The patients’ median age was 64 years old, and 51% were men. The actual ultrafiltration was 2 kg, and the mean TBW change measured using the InBody devices was 1.5 L (R² = 0.718) for the S10 and 1.7 L (R² = 0.616) for the 770. The estimated target weight at pre- and post-hemodialysis showed a remarkably high correlation with the patients’ actual pre- and post-hemodialysis weight (R² > 0.095). The correlation between these measurements (lying vs. standing) before and after hemodialysis was also very close (R² = 1.0000). In addition, ECW/TBW had a good correlation (R2 ≥ 0.970) The Bland-Altman test of dry weight and ECW/TBW yielded similar results.

Conclusions

This study showed that patients’ estimated target weights in the lying position using the InBody S10 device and in the standing position using the InBody 770 device were consistent in both pre- and post-hemodialysis states.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02737-3.

Quality of life in patients with diabetic nephropathy: findings from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease) cohort

Background

Diabetic nephropathy (DN) can affect quality of life (QoL) because it requires arduous lifelong management. This study analyzed QoL differences between DN patients and patients with other chronic kidney diseases (CKDs).

Methods

The analysis included subjects (n = 1,766) from the KNOW-CKD (Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease) cohort who completed the Kidney Disease Quality of Life Short Form questionnaire. After implementing propensity score matching (PSM) using factors that affect the QoL of DN patients, QoL differences between DN and non-DN participants were examined.

Results

Among all DN patients (n = 390), higher QoL scores were found for taller subjects, and lower scores were found for those who were unemployed or unmarried, received Medical Aid, had lower economic status, had higher platelet counts or alkaline phosphatase levels, or used clopidogrel or insulin. After PSM, the 239 matched DN subjects reported significantly lower patient satisfaction (59.9 vs. 64.5, p = 0.02) and general health (35.3 vs. 39.1, p = 0.04) than the 239 non-DN subjects. Scores decreased in both groups during the 5-year follow-up, and the scores in the work status, sexual function, and role-physical domains were lower among DN patients than non-DN patients, though those differences were not statistically significant.

Conclusion

Socioeconomic factors of DN were strong risk factors for impaired QoL, as were high platelet, alkaline phosphatase, and clopidogrel and insulin use. Clinicians should keep in mind that the QoL of DN patients might decrease in some domains compared with non-DN CKDs.

Low Muscle Mass in Patients Receiving Hemodialysis: Correlations with Vascular Calcification and Vascular Access Failure

Background: Sarcopenia involves an age-related decline in skeletal muscle mass with functional disability or low muscle strength. Vascular calcification (VC) occurs commonly in patients with chronic kidney disease, in whom it is associated with cardiovascular disease. We aimed to investigate the correlations of low muscle mass with the quantified vascular calcification score (VCS) of the arm of vascular access, as well as whether low muscle mass is associated with the incidence of vascular access failure. Methods: The VCS was measured on non-contrast, arm computed tomography using the Agatston method. The lower muscle mass (LMM) group comprised subjects whose skeletal muscle mass of the lower extremities, as measured using bioelectrical impedance, was lower than the median. Higher VC was defined as a score of 500 or above, corresponding to the highest 40% of VCS. The relationship between LMM and VC was explored using univariate and multivariate logistic regression analyses. Results: Seventy-five patients were included, of whom forty-two (56.0%) were men. The median age was 64 years (interquartile range 58-72 years). Of the 75 patients, 73 satisfied the diagnostic criteria for sarcopenia. The median hemodialysis vintage was 49.4 months (range 32.1-99.2 months). No significant differences were found between the non-LMM and LMM groups in sex, end-stage renal disease etiology, and type of vascular access, although the LMM group showed significantly older age and hemodialysis vintage. LMM presented a significant association with VC (hazard ratio (HR) 3.562; 95% CI, 1.341-9.463; p = 0.011). Upon adjustment for hemodialysis vintage, diabetes, and systolic blood pressure, LMM demonstrated an independent association with VC (HR, 10.415; 95% CI, 2.357-46.024; p = 0.002). The risk of vascular access failure was higher in the LMM group (HR, 3.652; 95%, CI 1.135-11.749; p = 0.03). VC was a full mediator in the relationship of LMM with recurrent vascular access failure. Conclusions: We quantified LMM via bioimpedance analysis and found a heretofore-unreported association between LMM and vascular access failure. LMM increases the risk of VC and has the potential to predict vascular access failure.