In the present study, we investigated the prevalence of disability in ADL and, for the first time, reported its relationship with PhA in patients on hemodialysis. The results indicated that disability in ADL was common in hemodialysis patients. Furthermore, our findings showed that low PhA was associated with disability in ADL in hemodialysis patients. We revealed that PhA was useful to screen for the presence of disability in ADL in hemodialysis patients, especially female patients.
BIA is a fast, safe, and non-invasive method used to estimate the body composition and nutritional state of healthy and ill individuals [11, 12]. As a piece of raw data from BIA, PhA has been investigated as a prognostic marker for mortality in many diseases, such as cancer, cardiac diseases, kidney diseases, and others [13–15]. Previous studies have shown that PhA could be used as a marker to reflect the nutritional status of patients with chronic kidney disease undergoing maintenance dialysis or not on dialysis [16, 17]. A retrospective cohort study showed that Bioelectrical impedance analysis-derived phase angle as a determinant of protein-energy wasting and frailty in maintenance hemodialysis patient[18]. It is well known that the simultaneous assessment and management of malnutrition as well fluid overload is particularly important because it can improve the prognosis of patients with End-stage renal disease (ESRD). Therefore, the BIA and PhA can be widely used in the ESRD population [17].
Functional ability is the actual or potential capacity of an individual to perform the activities and tasks that can be normally expected. Commonly, disability in ADL is assessed using the BADL and IADL scales [19]. As a result of protein–energy malnutrition and decreased exercise capacity, hemodialysis patients often lose mobility to the point of disability, which can lead to the inability to live independently [20, 21]. A small cross-sectional study of hemodialysis patients showed that more than 80% of patients had IADL disability, and the prevalence of BADL disability also exceeded 40% [22]. Similarly, another study showed that nearly 30% and more than 60% of hemodialysis patients had disabilities in ADL and IADL, respectively [23]. In this study, the prevalence of disability in BADL was 21.1%, that of disability in IADL was 41.4%, and that of disability in ADL was 43.5%. Therefore, disability is common in hemodialysis patients. Some studies demonstrated that patients with disability had a higher incidence and severity of post-dialysis fatigue [23]. It is worth noting that disability significantly increases the risk of death and is a strong predictor of mortality in hemodialysis patients [24, 25]. In this study, after adjustment for multiple variables, logistic regression analysis showed that low PhA remained strongly associated with disability in hemodialysis patients. Additionally, we found that PhA had good diagnostic accuracy for screening dependency. Thus, our findings suggest that PhA can be used as an important method for evaluating and screening disability in ADL in hemodialysis patients. Importantly, our findings also expand the latest understanding of the clinical value of PhA. In addition, we speculate that PhA might be used as a marker for predicting new-onset ADL disability.
There are several limitations in the study. First, as this was a single-center study, the generalizability of the study results might be limited. Second, this study adopted a cross-sectional design, so cause–effect relationships could not be established. Finally, the sample size was relatively small, and this may have masked other possible interactions.
In conclusion, our results indicated that a low PhA is closely related to disability in ADL in hemodialysis patients. In future studies, the relationship between PhA and new-onset disability in ADL can be further clarified, and it can be confirmed whether PhA can be used as an evaluation index to monitor functional improvement.