Effect of Behavioral Intervention on Interdialytic Weight Gain in Patients Undergoing Hemodialysis

Mortality among hemodialysis (HD) patients remains high with cardiovascular causes accounting for more than one-third of mortality in incident and prevalent end-stage renal disease (ESRD) patients. One factor contributing to poor cardiovascular outcomes is chronic volume overload ,which is a function of excess fluid intake in relation to residual renal function and fluid removal with dialysis treatments. Interdialytic weight gain (IDWG) is an easily measurable parameter in the dialysis unit, routinely assessed at the beginning of the dialysis session. Very few studies have been designed to determine the direct effect of IDWG on morbidity and mortality. Any such effect is confounded by residual renal function and various comorbidities, the effects of which might be difficult to separate from those of IDWG. Most attempts to control IDWG have concentrated on requiring patients to reduce fluid and dietary salt intake. Inter-dialytic weight gain is the result of salt and water intake between 2 hemodialysis sessions. Interdialytic weight gain (IDWG) is commonly used as an indirect measure of fluid intake in HD patients, while considering the daily urine output of the patient. It is used along with clinical symptoms and signs and predialysis blood pressure readings to make decisions regarding the amount of fluid removal during a dialysis session. IDWG is also used as a basis for fluid and salt intake recommendations. High IDWG has detrimental effects on survival, cardiovascular outcomes, and quality of life. A higher IDWG is associated with higher predialysis systolic and diastolic blood pressure ,uncontrolled hypertension which contributes to left ventricular hypertrophy, increasing intradialytic hypotension as a result of higher ultrafiltration rates , and increased morbidity and mortality.

High IDWG is due to poor adherence to fluid restriction and to excessive intake of fluids. Various strategies and interventions have been proposed to control IDWG such as the reduction of dietary salt intake, behavioral interventions aimed at improving the adherence to fluid restriction, the improvement of xerostomia, and the use of lower dialysate sodium concentration. Despite the severe consequences of non-adherence, it has been estimated that 30%-60% of hemodialysis patients do not adhere to a fluid intake guidelines. Various restrictions and barriers such as psychological (low motivation) or social (inadequate support from family, friends), lack of knowledge (lack of understanding of what they were advised), and lack of self-assessment (being unable to judge overall fluid status, fluid intake, or salt consumption) have been shown to be related to failed adherence to fluid restriction strategy. Strategies of behavioral intervention have been used to improve adherence to fluid restriction and to limit IDWG. These strategies aimed to improve motivation, knowledge, social support and education of hemodialysis patients. The behavioral interventions generally used included various approaches, such as behavioral contracting and weekly telephone contacts with patients, patient self-monitoring and behavioral contracting upon adherence, stepped verbal and written reinforcement, group-administered behavioral self-regulation intervention, group education sessions based on trans-theoretical model (states of change), self-efficacy training, and group or individual cognitive behavioral therapy. Numerous randomized controlled studies have been performed, but unfortunately, their results conflict and cannot permit conclusive considerations. It is difficult to compare such studies because of the differences in terms of duration and sample size. Consequently, it is hard to define if certain behavioral interventions are more effective than others. However, what emerges is that the behavioral intervention, although leading to a positive outcome, is temporary and has limited long-term effectiveness. Modest evidence suggests that behavioral intervention strategies (e.g., instruction in self-monitoring, behavioral contracting, and positive reinforcement) may be associated with improved adherence among hemodialysis patients.

The purpose of this behavioral study was to evaluate the efficacy of a technology-supported behavioral intervention (text message) for reducing IDWGs and dietary sodium intake in patients undergoing intermittent HD. The investigators have devised a relatively simplified behavioral intervention(a simple text message regarding fluid and salt restriction) as it will be easier and less cumbersome to perform owing to the educational status and level of understanding of the local population. Moreover, it is less expensive as compared to other interventions and less complicated. Another study which used text message as medium of communication depicted that smoking quit rates for the text messaging intervention group were 36% higher compared to the control group quit rates. Results also suggested that SMS text messaging technology might be a promising way to improve smoking cessation outcomes. This is significant given the relatively wide reach and low cost of text message interventions. Identifying the components that make interventions efficacious will help to increase the effectiveness of such interventions.