Measures of treatment burden in dialysis: A scoping review.

BACKGROUND: Dialysis is a life-sustaining treatment for patients with advanced kidney failure, but it is extremely burdensome. Despite this, there are very few tools available to assess treatment burden within the dialysis population. OBJECTIVE: To conduct a scoping review of generic and disease-specific measures of treatment burden in chronic kidney disease, and assess their suitability for use within the dialysis population. DESIGN: We searched CINAHL, MEDLINE and the Cochrane Library for kidney disease-specific measures of treatment burden. Studies were initially included if they described the development, validation or use of a treatment burden measure or associated concept (e.g., measures of treatment satisfaction, quality of life, illness intrusiveness, disease burden etc.) in adult patients with chronic kidney disease. We also updated a previous scoping review exploring measures of treatment burden in chronic disease to identify generic treatment burden measures. RESULTS: One-hundred and two measures of treatment burden or associated concepts were identified. Four direct measures and two indirect measures of treatment burden were assessed, using adapted established criteria, for suitability for use within the dialysis population. The researchers outlined eight key dimensions of treatment burden: medication, financial, administrative, lifestyle, health care, time/travel, dialysis-specific factors, and health inequality. None of the measures adequately assessed all dimensions of treatment burden. CONCLUSION: Current measures of treatment burden in dialysis are inadequate to capture the spectrum of issues that matter to patients. There is a need for dialysis-specific burdens and health inequality to be assessed when exploring treatment burden to advance patient care.

Energy expenditure estimates in chronic kidney disease using a novel physical activity questionnaire.

BACKGROUND: Physical activity (PA) levels are low in patients with advanced chronic kidney disease (CKD), and associate with increased morbidity and mortality. Reliable tools to assess PA in CKD are scarce. We aimed to develop and validate a novel PA questionnaire for use in CKD (CKD-PAQ). METHODS: In Phase 1, a prototype questionnaire was developed based on the validated recent PAQ (RPAQ). Structured feedback on item relevance and clarity was obtained from 40 CKD patients. In Phase 2, the questionnaire was refined in three iterations in a total of 226 CKD patients against 7-day accelerometer and RPAQ measurements. In Phase 3, the definitive CKD-PAQ was compared with RPAQ in 523 CKD patients. RESULTS: In the final iteration of Phase 2, CKD-PAQ data were compared with accelerometer-derived and RPAQ data in 60 patients. Mean daily metabolic equivalent of task (MET) and total energy expenditure (TEE) levels were similar by all methods. Intraclass correlation coefficients showed fair (MET) and good (TEE) agreement between accelerometry and both CKD-PAQ and RPAQ. Agreement between questionnaires was excellent. The mean [standard deviation (SD)] daily MET bias was 0.035 (0.312) for CKD-PAQ and 0.018 (0.326) for RPAQ. The mean (SD) TEE bias was 91 (518) for CKD-PAQ and 44 (548) kcal for RPAQ. Limits of agreement (LOA) were wide for both parameters, with less dispersion of CKD-PAQ values. In Phase 3, agreement between questionnaires was good (MET) and excellent (TEE). Bias of CKD-PAQ-derived mean (SD) daily MET from RPAQ-derived values was 0.031 (0.193), with 95% LOA -0.346 to 0.409. Corresponding mean (SD) values for TEE were 48 (325) and -588 to 685 kcal/day. CKD-PAQ appeared to improve discrimination between low activity groups. CONCLUSIONS: CKD-PAQ performs comparably to the RPAQ though it is shorter, easier to complete, and may better capture low-level activity and improve discrimination between low activity groups.

The role of natriuretic peptides in volume assessment and mortality prediction in Haemodialysis patients.

BACKGROUND: Maintaining optimal fluid balance is essential in haemodialysis (HD) patients but clinical evaluation remains problematic. Other technologies such as bioimpedance are emerging as valuable adjuncts. This study was undertaken to explore the potential utility of the natriuretic peptides - atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) in the assessment of fluid status and cardiovascular risk in this setting. METHODS: This was a cross-sectional study carried out in an unselected cohort of 170 prevalent HD patients. Volume status was assessed by clinical parameters - the presence or absence of peripheral oedema, raised jugular venous pressure and basal lung crepitations; by extracellular fluid volume (ECFV) status determined by whole body bioimpedance; and by serum levels of BNP and ANP (pre- and post -dialysis). The relationships of ANP and BNP levels to clinical and bioimpedance parameters of volume status was determined. Patients were followed up for 5 years to assess the relationship of natriuretic peptide levels to mortality. RESULTS: Bioimpedance estimates of ECFV expansion (>105 % of ideal ECFV) was present in 52 % of patients pre-dialysis. A significant proportion (21 %) of pre-dialysis patients had a depleted ECFV (<95 % of ideal ECFV) pre-dialysis. The situation was reversed post-dialysis. A raised JVP >3 cm was the most reliable clinical sign of ECFV expansion inferred from bioimpedance measurements and natriuretic peptide levels. The vast majority of patients with this sign also had lung crepitations or peripheral oedema or both. BNP was a stronger predictor of ECFV expansion than either pre- or post-dialysis ANP. BNP was also a stronger predictor of five-year survival. CONCLUSION: Serum levels of BNP have a strong relationship to both volume status and survival in HD patients. We found no clear role for measurement of ANP, though changes in blood levels may be a sensitive indicator of acute changes in volume status. Whether monitoring levels of these peptides has a role in the management of volume status and cardiovascular risk requires further study.

Disease-specific predictive formulas for energy expenditure in the dialysis population.

OBJECTIVE: Metabolic rate is poorly understood in advanced kidney disease because direct measurement is expensive and time-consuming. Predictive equations for resting energy expenditure (REE) are needed based on simple bedside parameters. Algorithms derived for normal individuals may not be valid in the renal population. We aimed to develop predictive equations for REE specifically for the dialysis population. DESIGN: Two-hundred subjects on maintenance dialysis underwent a comprehensive metabolic assessment including REE from indirect calorimetry. Parameters predicting REE were identified, and regression equations developed and validated in 20 separate subjects. RESULTS: Mean REE was 1,658 ± 317 kCal/day (males) and 1,380 ± 287 kCal/day (females). Weight and height correlated positively with REE (r(2) = 0.54 and 0.31) and negatively with age older than 65 years (r(2) = 0.18). The energy cost of a unitary kilogram of body weight increased nonlinearly for lower body mass index (BMI). Existing equations derived in normal individuals underestimated REE (bias 50-114 kCal/day for 3 equations). The novel derived equation was REE(kCal/day) = -2.497·Age·Factorage+0.011·height(2.023) + 83.573·Weight(0.6291) + 68.171·Factorsex, where Factorage = 1 if 65 years or older and 0 if younger than 65, and Factorsex = 1 if male and 0 if female. This algorithm performed at least as well as those developed for normals in terms of limits of agreement and reduced bias. In validation with the Bland-Altman technique, bias was not significant for our algorithm (-22 ± 96 kCal/day). The 95% limits of agreement were +380 to -424 kCal/day. CONCLUSION: Existing equations for REE derived from normal individuals are not valid in the dialysis population. The relatively increased REE in those with low BMI implies the need for higher dialysis doses in this subgroup. This disease-specific algorithm may be useful clinically and as a research tool to predict REE.