RESUMO
BACKGROUND: Among people with chronic kidney disease (CKD) on dialysis, sub-optimal fluid management has been linked with hospitalisation, cardiovascular complications and death. This study assessed the cost-effectiveness using multiple-frequency bioimpedance guided fluid management versus standard fluid management based on clinical judgment. METHODS: A Markov model was developed to compare expected costs, outcomes and quality adjusted life years of the alternative management strategies. The relative effectiveness of the bioimpedance guided approach was informed by a systematic review of clinical trials, and focussed reviews were conducted to identify baseline event rates, costs and health state utility values for application in the model. The model was analysed probabilistically and a value of information (VOI) analysis was conducted to inform the value of conducting further research to reduce current uncertainties in the evidence base. RESULTS: For the base-case analysis, the incremental cost-effectiveness ratio (ICER) for bioimpedance guided fluid management versus standard management was £16,536 per QALY gained. There was a 59% chance of the ICER being below £20,000 per QALY. Form the VOI analysis, the theoretical upper bound on the value of further research was £53 million. The value of further research was highest for parameters relating to the relative effectiveness of bioimpedance guided management on final health outcomes. CONCLUSIONS: Multiple frequency bioimpedance testing may offer a cost-effective approach to improve fluid management in patients with CKD on dialysis, but further research would be of value to reduce the current uncertainties.
RESUMO
Rationale: Anemia, a common feature in chronic kidney disease (CKD), has multiple contributors to its pathogenesis. Besides the well recognized erythropoietin and iron deficiencies, hydration status might be involved. Objective: To assess the prevalence and correlations of anemia, iron deficiency and overhydration in patients with stage 2 to 5 CKD. Methods and Results: This cross-sectional study enrolled 125 erythropoietin and iron therapy naïve non-dialysis CKD patients, without a identifiable cause of anemia. Parameters of hematological, iron, inflammatory and nutritional status were measured. The overhydration parameter (OH) assessed by bioimpedance spectroscopy was used to characterize hydration status. The prevalence of decreased hemoglobin (Hb) <110g/L increased along CKD stages from 0% to 40% (p=0.008). Fluid overload (OH >1L) and lower serum albumin (<40g/L) were more common in stage 5 versus stage 3 CKD (53% vs. 10%, p<0.001, and 27% vs. 3%, p=0.02, respectively), suggesting a potential dilutional reduction in serum proteins. Conversely, decreased iron stores (ferritin <100mcg/L) and iron availability (transferrin saturation, TSAT<0.20) were similarly prevalent irrespective of kidney function decline. Hemoglobin was positively correlated with estimated glomerular filtration rate (eGFR), serum albumin, and transferrin saturation, but inversely with OH. However, in a model of multiple linear regression which explained 32% of hemoglobin variation, only eGFR and overhydration remained the independent predictors of anemia. Discussion: As fluid overload is a common denominator for hemoglobin and TSAT levels, and is closely related to the declining kidney function, it should be considered in the management of renal anemia, at least in advanced CKD.