Nwosu, Amara Callistus, Stanley, Sarah, Mayland, Catriona R, Mason, Stephen, McDougall, Alexandra, and Ellershaw, John E
Background: Oral fluid intake decreases in advanced cancer in the dying phase of illness. There is inadequate evidence to support the assessment, and management, of hydration in the dying. Bioelectrical impedance analysis (BIA) is a body composition assessment tool. BIA has the potential to inform clinal management in advanced cancer, by examining the relationships between hydration status and clinical variables. Aim: BIA was used to determine the association between hydration status, symptoms, clinical signs, quality-of-life and survival in advanced cancer, including those who are dying (i.e. in the last week of life). Materials and methods: We conducted a prospective observational study of people with advanced cancer in three centres. Advance consent methodology was used to conduct hydration assessments in the dying. Total body water was estimated using the BIA Impedance index (Height – H (m)2 /Resistance – R (Ohms)). Backward regression was used to identify factors (physical signs, symptoms, quality of life) that predicted H2/R. Participants in the last 7 days of life were further assessed with BIA to assess hydration changes, and its relationship with clinical outcomes. Results: One hundred and twenty-five people participated (males n = 74 (59.2%), females, n = 51 (40.8%)). We used backward regression analysis to describe a statistical model to predict hydration status in advanced cancer. The model demonstrated that 'less hydration' (lower H2/R) was associated with female sex (Beta = -0.39, p < 0.001), increased appetite (Beta = -0.12, p = 0.09), increased dehydration assessment scale score (dry mouth, dry axilla, sunken eyes - Beta = -0.19, p = 0.006), and increased breathlessness (Beta = -0.15, p = 0.03). 'More hydration' (higher H2/R) was associated with oedema (Beta = 0.49, p < 0.001). In dying participants (n = 18, 14.4%), hydration status (H2/R) was not significantly different compared to their baseline measurements (n = 18, M = 49.6, SD = 16.0 vs. M = 51.0, SD = 12.1; t(17) = 0.64, p = 0.53) and was not significantly associated with agitation (rs = -0.85, p = 0.74), pain (rs = 0.31, p = 0.23) or respiratory tract secretions (rs = -0.34, p = 0.19). Conclusions: This is the first study to use bioimpedance to report a model (using clinical factors) to predict hydration status in advanced cancer. Our data demonstrates the feasibility of using an advance consent method to conduct research in dying people. This method can potentially improve the evidence base (and hence, quality of care) for the dying. Future BIA research can involve hydration assessment of cancers (according to type and stage) and associated variables (e.g., stage of illness, ethnicity and gender). Further work can use BIA to identify clinically relevant outcomes for hydration studies and establish a core outcome set to evaluate how hydration affects symptoms and quality-of-life in cancer. Key message: What is already known about this topic? - Oral fluid intake decreases in people with advanced cancer, especially when they approach the dying phase of their illness. - There is inadequate evidence to support hydration assessment and decision making in the dying phase of illness. - It is important to understand which clinical factors are associated with hydration status in advanced cancer, to enable healthcare professionals, to evaluate hydration status and support clinical decision making. - Bioimpedance is a non-invasive technology, which has potential to identify clinically relevant variables for cancer hydration assessment. What this paper adds. - This is the first study to use bioimpedance to report a model (using clinical factors) to predict hydration status in advanced cancer. - The variables with combined significance for predicting hydration status were biological sex, appetite, dry mouth, dry axilla, sunken eyes, breathlessness and oedema. In the dying phase, hydration status did not significantly change compared to baseline, and hydration status was not significantly associated with survival. Implications for practice, theory or policy. - Further work can use bioimpedance to identify clinically relevant outcomes for hydration studies, to establish a core outcome set to evaluate how hydration affects symptoms and quality-of-life in cancer. [ABSTRACT FROM AUTHOR]