Large Interdialytic Weight Gains: Causes, Consequences, and Corrective Measures

Design of a randomized controlled clinical trial assessing dietary sodium restriction and hemodialysis-related symptom profiles

Aim

In hemodialysis patients, the need to have intercurrent sodium and water intake removed by ultrafiltration increases disease burden through the symptoms and signs that occur during hemodialysis (HD). This added burden may be mitigated by reduction of dietary sodium intake. The National Kidney Foundation (NKF) recommends 2400 mg of dietary sodium daily for patients on HD, and the American Heart Association (AHA) suggests 1500 mg, evidence is lacking, however, to support these recommendations in HD. Moreover, little is known about the relationship of specific levels of dietary sodium intake and the severity of symptoms and signs during ultrafiltration. Our goal will be to determine the effects of carefully-monitored levels of sodium-intake as set forth by the NKF and AHA on symptoms and signs in patients undergoing (HD).

Methods

We designed a three-group (2400 mg, 1500 mg, unrestricted), double blinded randomized controlled trial with a sample of 42 HD participants to determine whether 1. Symptom profiles and interdialytic weight gains vary among three sodium intake groups; 2. The effect of HD-specific variables on the symptom profiles among the three groups and 3. Whether total body water extracellular volume and intracellular volume measured with bioimpedance varies across the three groups. We will also examine the feasibility of recruitment, enrollment, and retention of participants for the five-day inpatient stay.

Conclusion

Curbing dietary sodium intake may lead to improvement in intradialytic symptom amelioration and potential for better long-term outcomes. Generating empirical support will be critical to ascertain, and espouse, the appropriate level of sodium intake for patients receiving HD.

The Effect of Psychological Intervention on Thirst and Interdialytic Weight Gain in Patients on Chronic Hemodialysis: A Randomized Controlled Trial

OBJECTIVE

Patients on hemodialysis (HD) are unable to eliminate excess fluid and must adhere to a regimen of dietary fluid restriction to prevent volume overload. Thirst represents a major obstacle to the achievement of such a goal. The aim of our study was (1) to assess the association of thirst and xerostomia, measured by validated questionnaires, Dialysis Thirst Inventory and Xerostomia Inventory with interdialytic weight gain (IDWG) and (2) to evaluate in a randomized controlled trial (RCT), the effect of psychological intervention on IDWG and thirst.

STUDY DESIGN

Cross-sectional evaluation of association of thirst and IDWG and single-blind RCT of psychological intervention on IDWG management.

SETTING

Outpatient dialysis unit.

SUBJECTS

The cross-sectional evaluation included 117 patients on HD (age, 71 ± 13 years); among these, 54 were selected for the RCT.

INTERVENTION

The questionnaires were administered to all the participating patients; IDWG (4-week average), Kt/V, predialysis blood pressure, dialyzate sodium, hematocrit, serum electrolytes, parathyroid hormone, and patients' medications were recorded. Fifty-four patients were randomized on a 1:1 basis to usual treatment (including dietary advice) or psychological intervention, consisting of group sessions, held once a week for 5 weeks; IDWG and all the other parameters were rechecked after 6 weeks and 6 months.

MAIN OUTCOME MEASURE

IDWG change from baseline.

RESULTS

Dialysis Thirst Inventory score was correlated with IDWG (ρ = 0.575; P < .001), body mass index (ρ = 0.257; P = .005), and inversely with age (ρ = -0.344; P < .001). A small but significant decrease of IDWG compared to baseline was observed in the intervention group (baseline 1332 ± 338 g/day; at 6 weeks, 1183 ± 258 g/day; at 6 months, 1203 ± 284 g/day; P < .001). No IDWG changes with respect to baseline occurred in controls (baseline 1310 ± 333 g/day; at 6 weeks, 1336 ± 340 g/day; at 6 months, 1323 ± 328 g/day; P = .57). The secondary outcomes were not affected by the intervention.

CONCLUSIONS

The findings of our study show that a psychological support may help managing IDWG in HD patients.

Lower serum potassium combined with lower sodium concentrations predict long-term mortality risk in hemodialysis patients

BACKGROUND

The purpose of this study was to evaluate the combined effect of different pre-hemodialysis (HD) serum sodium (S[Na]) and potassium (S[K]) concentrations on the long-term prognosis of HD patients.

METHODS

A cohort of 424 maintenance HD patients (age: 58 ± 13 years, male: 47%, diabetes: 39%) from a single center were divided into four groups based on both medians of S[Na] (138.4 mmol/L) and S[K] (4.4 mmol/L): Group 1: lower S[Na] & lower S[K]: n = 92; Group 2: lower S[Na] & higher S[K]: n =113; Group 3: higher S[Na] & lower S[K]: n =123; Group 4: higher S[Na] & higher S[K]: n =96. The median observation period was 21 months.

RESULT

By multivariate logistic regression analysis, Group 1 was characterized by hypoalbuminemia (OR = 0.37, 95%CI = 0.20-0.67), and lower normalized protein catabolism rate (nPCR) (OR = 0.37, 95% CI = 0.16-0.83). In contrast, Group 4 was characterized by higher nPCR (OR = 2.26, 95% CI = 1.05-4.86) and albumin level (OR = 2.26, 95% CI = 1.17-4.39). As compared to the reference (group 1), the HR for long-term mortality was significantly lower in Groups 3 (HR = 0.54, 95% CI = 0.34- 0.86) and 4 (HR = 0.49, 95% CI = 0.28-0.84). By multivariate Cox proportional analysis, Group 1 was an independent factor (HR = 1.74, 95% CI = 1.18-2.58) associated with long-term mortality.

CONCLUSION

HD patients combined with lower S[K] and lower S[Na] were characterized by hypoalbuminemia, lower nPCR and a high prevalence of co-morbidity. They were associated with long-term mortality risk. On the other hand, those patients with higher levels of S[Na] and S[K] tended to have better clinical outcomes.

Ultrafiltration rate as a nursing-sensitive quality indicator in haemodialysis

Nursing quality indicators are widely used to demonstrate nurses' contributions to health care. Some studies in nephrology settings have addressed nursing quality, but indicators reflecting the nursing process quality in haemodialysis are lacking. This paper argues for considering ultrafiltration rate as a nursing-sensitive quality indicator in haemodialysis. Strategies and qualifications for considering ultrafiltration rate as a nursing quality indicator are established and discussed. It is argued that the indicator is associated with nursing practice, linked to both morbidity and mortality, and is within the scope of the nurse's responsibility. It is also argued that the indicator could be influenced by other factors than nursing care. Thus, further studies are needed to investigate the association between ultrafiltration rate and patient safety. The introduction of the ultrafiltration rate as a duty specific quality indicator is a coveted measure of nursing care quality in haemodialysis settings.

Self-efficacy in relation to limited fluid intake amongst Portuguese haemodialysis patients

Self-efficacy is a temporary and influenceable characteristic, related to situations and tasks, mediating health-promoting behaviours. This study aimed to evaluate psychometric properties of a Portuguese version of the Fluid Intake Appraisal Inventory, and to describe self-efficacy in relation to limited fluid intake amongst Portuguese haemodialysis patients. Respondents were recruited from three dialysis units, and 113 of 155 eligible patients gave their informed consent. The translated scale was distributed and collected by the head nurses. Interdialytic weight gain was calculated as percentage of dry weight. Satisfactory psychometric properties were estimated in the Portuguese context. The participants' self-efficacy in relation to low fluid intake was asymmetrically distributed; the majority had moderately to high self-efficacy while some patients had very low self-efficacy to limited fluid intake. There was a significant difference in self-efficacy to fluid restrictions; patients with a weight gain of 3.5% or less presented higher self-efficacy scores than did patients exceeding the cutoff point.

Fluid Intake Appraisal Inventory: development and psychometric evaluation of a situation-specific measure for haemodialysis patients' self-efficacy to low fluid intake

OBJECTIVE

Self-efficacy is an important determinant of health behaviour and reflects a person's belief about their capability to complete a given task. The relationship between self-efficacy and fluid adherence has been investigated, although limited attention has been given to measurement issues. The purpose of this study was to develop a measure of situation-specific self-efficacy for constructive fluid intake behaviour in haemodialysis patients, the Fluid Intake Appraisal Inventory (FIAI).

METHODS

Items were generated from an analysis of empirical studies available in the literature and exposed to an interpretability critique before haemodialysis patients confirmed sufficiency of each item. In a multi-centre study, data from 144 haemodialysis patients were collected regarding general self-efficacy, situation-specific self-efficacy, and estimated fluid consumption. Internal consistency, criterion-related validity, and structural validity were tested.

RESULTS

The FIAI was found to have high internal consistency (Cronbach alpha 0.96) and the theoretical assumptions for criterion-related validity and known-group validity were supported. Structural validity was not confirmed, however, because the theoretically hypothesized four-factor model was not the prime structure.

CONCLUSION

The FIAI was revealed to have satisfactory psychometric properties. The scale may be used in research or in clinical settings to study the mediating effects of self-efficacy or to modify haemodialysis patients' fluid-intake behaviour. Although this first validity study is promising, further validation focusing on reliability and cultural validity is needed.

Fellows' Forum in Dialysis: Interdialytic Weight Gain: Implications in Hemodialysis Patients

Interdialytic weight gain (IDWG) is an easily measurable parameter in the dialysis unit, routinely assessed at the beginning of the dialysis session. 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. However, advising fluid and salt restriction based solely on IDWG may not be appropriate because of its status as a nutritional indicator, as well. 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. Although there does not seem to be a consensus at this point, it is likely that within the lower values of IDWG (less than 5.7% of dry weight), tighter control of fluid and salt intake might not be warranted since these values may reflect higher protein and calorie intake, indicating better nutritional status.

A systematic review of psychological interventions for the treatment of nonadherence to fluid-intake restrictions in people receiving hemodialysis

BACKGROUND

Psychological interventions aimed at improving adherence to fluid-intake restrictions in patients receiving hemodialysis have become increasingly common. To the authors' knowledge, this is the first systematic review of the literature examining the impact of these interventions associated with patient interdialytic weight gain (IWG).

METHODS

A systematic search of the literature was performed on EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and PsychINFO. The search was augmented by manually examining reference lists of reviews and retrieved reports. Study quality was graded according to criteria developed by the authors. Two additional independent researchers separately coded a random sample of studies to avoid bias of rating.

RESULTS

Sixteen studies were identified as eligible for inclusion. Relevant information from each included study was extracted and entered into a standardized table. Nearly all studies showed a postintervention decrease in IWG. A number of method weaknesses in the existing literature were identified.

CONCLUSION

Studies investigating psychological interventions aimed at improving adherence to fluid-intake restrictions appear to indicate some success in decreasing IWG. However, confidence regarding the validity of this finding is circumscribed by the prevalent use of investigative designs with inherently high susceptibility to bias. Future studies would benefit from using larger numbers of participants within controlled designs. Clearer description of intervention protocols would foster greater understanding of the contextual appropriateness of different approaches and which treatment components are key to improving adherence to fluid-intake restrictions in patients receiving hemodialysis.

Adjustment of hemodialysis dose for residual renal urea clearance: a two year study of impact on dialysis time

Urea kinetic modeling suggests that significant time reductions may be realized in hemodialysis patients with residual renal urea clearance (K(r)t/V urea). However, the actual impact of a strategy that integrates such function into the dialysis prescription is not clear, because of both uncertainty regarding the rate of decay of K(r)t/V urea, as well as potential clinical constraints upon dose reduction. To examine this issue, we retrospectively reviewed data from 51 patients with K(r)t/N urea after initiation of maintenance hemodialysis. In 31 cases, there were no clinical barriers to adjustment of the dialysis prescriptions. Regression analysis revealed that each 0.10 increment in K(r)t/V urea yielded an actual dialysis time reduction of 12 minutes per week with average cumulative reduction of 80 minutes per week per patient. At approximately 1 year after initiation of dialysis, there were still 10 patients whose dialysis prescriptions were being adjusted on the basis of K(r)t/V urea. In conclusion, our results suggest that the incorporation of K(r)t/V urea in the hemodialysis prescription allows for substantial and enduring reductions in dialysis time in a significant minority of patients. Larger prospective studies are needed to evaluate the long-term safety of this strategy in modifying the dose of hemodialysis.

Reported pica behavior in a sample of incident dialysis patients

In a prospective study, pica behavior was investigated during baseline interviews with a cohort of incident patients (n = 226) who began chronic dialysis therapy in metropolitan Atlanta, GA, during 1996 to 1997. Pica, defined as current pica behavior and/or reported history of pica behavior, was reported by 16% of the sample. Patients reporting pica were significantly more likely to be African American women and were significantly younger than the remainder of the sample. Approximately two thirds of patients who reported pica behaviors craved and excessively consumed ice; the remainder craved and consumed starch, dirt, flour, or aspirin. Among patients reporting pica, average serum albumin values were low and average phosphorus was increased. The average hematocrit of patients reporting ice pica was low. Over half of the hemodialysis patients reporting pica behavior had excessive usual interdialytic weight gain. Potential symptoms/problems affecting quality of life among patients practicing pica, eg, cramps, are shown in a case report. The data indicate the need for targeted education and support for dietitians' increased interaction with dialysis patients involved in pica behaviors.