Fluid Distribution Timetable on Adherence to Fluid Restriction of Patients With End-Stage Renal Disease Undergoing Hemodialysis: A Single-Blind, Randomized-Controlled Pilot Study

End-stage renal disease (ESRD), defined as a condition in which the kidneys are damaged or cannot filter blood similar to a healthy kidney (Centers for Disease Control and Prevention, 2017), is a rising global dilemma. In fact, it has been a leading cause of morbidity and mortality worldwide, afflicting approximately 8% - 16% of the global population (Jha et al., 2013) and ranking eighth among the leading causes of death. It has also been acknowledged as a troublesome disorder causing a myriad of health-related problems (Lowney et al., 2015), financial burden (Bavanandan et al., 2016), and poor survival outcomes (Halle et al., 2016).

Hemodialysis, a form of renal replacement treatment, has been the mainstream management for patients with kidney diseases (Smeltzer et al., 2010) despite several health complications (Smeltzer et al., 2010; Lowney et al., 2015). However, dietary and fluid therapy are also necessary components of the management for patient with ESRD. A common concern among patients on hemodialysis is the non-adherence to fluid therapy. Although this management is simple, it remains a challenge to patients on hemodialysis because of several physiologic changes brought by ESRD. As a result, numerous problems such as fluid overload, electrolyte imbalances, and acid-base imbalances occur which are detrimental to the patient's overall health. Since patients on hemodialysis are the key players in promoting their health, it is, therefore, imperative to develop individualized and empowering strategies what will promote their adherence to fluid therapy. The proposed strategy in this study is the fluid distribution timetable, a simple and health promotive intervention involving scheduled distribution of pre-determined amounts of fluid intake on a daily basis. This intervention consider the various sources and usage of fluids per day and allocates fluid intake according to the patient's prescribed fluid restriction. Hence, this study determined the effects of a fluid distribution timetable on adherence to fluid restriction of patients with end-stage renal disease undergoing hemodialysis.

This study is a single-blind, single-center, randomized-controlled pilot study at the dialysis unit of a tertiary level government-owned institution in Quezon City, Philippines. Patients were randomly-allocated to receive fluid distribution timetable with standard care (intervention) or standard care alone (control). Random allocation of respondents was conducted using computer-generated sequences of randomly permuted blocks (sizes of three, four, and five) at our office. Randomization was carried out by an independent statistician and was stratified according to their sex. During the study period, treatment allocation was masked from site personnel and patients. Post-hoc power analysis for two group means, using GPower version 3.1, revealed that a sample size of 24 patients with a 1:1.20 group allocation ratio yields a power of 99% at a significance of 5% (two-sided) and detects an effect size of 0.80.

The control group received the standard care for patients on hemodialysis. The standard care involves a 10 -15-minute face-to-face health teaching of their treatment regimen including pharmacologic management, dialysis schedule, dietary and fluid restrictions or nutritional therapy, care for vascular access, and other necessary lifestyle modifications. The treatment group, on the other hand, received a combination of the standard care and the intervention, the fluid distribution timetable. It is a scheduled distribution of pre-determined amounts of fluid intake on a daily basis depicted via a 5x6 table. The timetable includes three major columns. The first column has six timepoints of a day with a four-hour interval. The second column, which was further divided into four sub-columns, reflects the percentage of fluid allotment for food, activities, medication, and thirst encounters. The percentage of fluid allocation was computed based on the patient's prescribed fluid restriction, usual time of food intakes in a day, usual level of activity, time of medication intake, and common time they encounter thirst in a day. Lastly, the third column indicates the converted percentages of fluid allotment in milliliters. In designing the intervention, we selected three behavior-specific cognitions from the Health Promotion Model by Nola J. Pender: perceived benefits, barriers, and self-efficacy. These cognitions are modifiable determinants of behavior that promote well-being. As such, the fluid distribution timetable enumerated the advantages of adherence and the disadvantages of non-adherence to fluid restriction.

Adherence to fluid restriction was measured using two indicators - thirst and interdialytic weight gain - and were compared using One-way RM-MANOVA and MANCOVA. Thirst was measured using a self-reported questionnaire the Dialysis Thirst Inventory, while interdialytic weight gain computed using a calibrated calculator by subtracting post-dialysis weight at the end of the previous hemodialysis session from the pre-dialysis weight during the current hemodialysis session. Secondary outcomes included baseline patient demographic and clinical characteristics and were compared according to treatment allocation. Both groups were followed-up for four weeks, assessing outcome measures during the second hemodialysis session for each week.