The diet and haemodialysis dyad: Three eras, four open questions and four paradoxes. A narrative review, towards a personalized, patient-centered approach

The history of dialysis and diet can be viewed as a series of battles waged against potential threats to patientsâ\u80\u99 lives. In the early years of dialysis, potassium was identified as â\u80\u9cthe killerâ\u80\u9d, and the lists patients were given of forbidden foods included most plant-derived nourishment. As soon as dialysis became more efficient and survival increased, hyperphosphatemia, was identified as the enemy, generating an even longer list of banned aliments. Conversely, the â\u80\u9cthird eraâ\u80\u9d finds us combating protein-energy wasting. This review discusses four questions and four paradoxes, regarding the diet-dialysis dyad: are the â\u80\u9cmagic numbersâ\u80\u9d of nutritional requirements (calories: 30â\u80\u9335 kcal/kg; proteins > 1.2 g/kg) still valid? Are the guidelines based on the metabolic needs of patients on â\u80\u9cconventionalâ\u80\u9d thrice-weekly bicarbonate dialysis applicable to different dialysis schedules, including daily dialysis or haemodiafiltration? The quantity of phosphate and potassium contained in processed and preserved foods may be significantly different from those in untreated foods: what are we eating? Is malnutrition one condition or a combination of conditions? The paradoxes: obesity is associated with higher survival in dialysis, losing weight is associated with mortality, but high BMI is a contraindication for kidney transplantation; it is difficult to limit phosphate intake when a patient is on a high-protein diet, such as the ones usually prescribed on dialysis; low serum albumin is associated with low dialysis efficiency and reduced survival, but on haemodiafiltration, high efficiency is coupled with albumin losses; banning plant derived food may limit consumption of â\u80\u9cvascular healthyâ\u80\u9d food in a vulnerable population. Tailored approaches and agreed practices are needed so that we can identify attainable goals and pursue them in our fragile haemodialysis populations

Positron Emission Tomography Can Support the Diagnosis of Dialysis-Related Amyloidosis

Background: The improvements in dialysis have not eliminated long-term problems, including dialysis-related amyloidosis (DRA), caused by Beta-2 microglobulin deposition. Several types of scintigraphy have been tested to detect DRA, none entered the clinical practice. Aim of the study was to assess the potential of PET-FDG scan in the diagnosis of DRA. Methods: Forty-six dialysis patients with at least one PET scan (72 scans) were selected out 162 patients treated in 2016–2018. Subjective global assessment (SGA), malnutrition inflammation score (A), Charlson Comorbidity Index (CCI), were assessed at time of scan; 218 age-matched cases with normal kidney function were selected as controls. PET scans were read in duplicate. Carpal tunnel syndrome was considered a proxy for DRA. A composite “amyloid score” score considered each dialysis year = 1 point; carpal tunnel-DRA = 5 points per site. Logistic regression, ROC curves and a prediction model were built. Results: The prevalence of positive PET was 43.5% in dialysis, 5% in controls (p < 0.0001). PET was positive in 14/15 (93.3%) scans in patients with carpal tunnel. PET sensitivity for detecting DRA was 95% (specificity 64%). Carpal tunnel was related to dialysis vintage and MIS. A positive PET scan was significantly associated with dialysis vintage, MIS and amyloid score. A prediction model to explain PET positivity combined clinical score and MIS, allowing for an AUC of 0.906 (CI: 0.813–0.962; p < 0.001). Conclusions: PET-FDG may identify DRA, and may be useful in detecting cases in which inflammation favours B2M deposition. This finding, needing large-scale confirmation, could open new perspectives in the study of DRA