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.