Rafael Selgas

Background: Human fibroblast growth factor 21 (FGF21) is a new liver hormone that stimulate adipocyte glucose uptake and is involved in regulation of body fat. Objective: To define the natural history of FGF21 in peritoneal dialysis (PD) patients and analyze its relationship with glucose metabolism, peritoneal function, and residual renal function (RRF). Methods: We studied 48 uremic patients undergoing PD. Patients were evaluated at baseline, and 1, 2 and 3 years after starting PD. At each evaluation, clinical status, biochemical parameters (including FGF21, glucose, insulin, homeostatic model assessment of insulin resistance index (HOMA-IR) and non-esterified fatty acids concentration (NEFA)), and peritoneal function parameters were assessed. Results: Plasma FGF21 concentrations significantly increased over the first year and maintained at high levels during the rest of the study period, especially among non-diabetic patients (n=37, baseline 253 (59–685) vs 647 (121–1117) pg/ml at third year, PPρ=−0.484, Pρ=0.410, PPPP<0.05), independently of the time on dialysis. Conclusion: FGF21 plasma levels importantly increase during PD therapy. This increment is associated with RRF and PPL. The absence of increment in insulin resistance in spite of maintained peritoneal glucose load suggests that FGF-21 might behave as a protective factor against insulin resistance.

Health-related quality of life (HRQOL) has been widely studied in the field of dialysis patients. However, there are few studies that include relationships of psychosocial variables and adherence to treatment with HRQOL. The aim of this review is to systematically synthesise available information on the role that psychological variables (depression, anxiety and stress) and adherence to treatment have on HRQOL of dialysis patients through a systematic narrative review. We selected studies that included and related, in their results psychological variables (at least one of the following: depression, anxiety or perceived stress), adherence to treatment and HRQOL in adults on dialysis due to advanced chronic kidney disease (ACKD). The studies included had to incorporate standardised instruments into their assessment protocol. We searched the MEDLINE and PsycINFO databases from January 2002 to August 2012. Thirty-eight studies were included in this review and we assessed their methodological quality. The review revealed that 100% of the studies identified a negative association between indicators of anxiety, depression and stress and HRQL, indicating that these variables are risk factors for quality of life. Adherence to treatment was associated with psychological factors and HRQOL in 8% (N=3) of the studies included and has been demonstrated to be a protective factor for quality of life in 66% of studies (2 of 3) that included this variable. Considering the effect of these variables on HRQOL, it is important to screen for early indicators of anxiety, stress and depression or difficulties in complying with treatment in the ACKD population on dialysis. This will allow preventive interventions to be carried out before HRQOL deteriorates.

Undergoing a haemodialysis (HD) session poses a certain risk of hypersensitivity adverse reactions as large quantities of blood are in contact with various synthetic materials. Hypersensitivity reactions to ethylene oxide and non-biocompatible membranes, such as cuprophane, have been described in HD. Cases of hypersensitivity with biocompatible membranes, such as polysulfone, and even polysulfone-polyvinylpyrrolidone, have also been reported. In this article we describe six cases of mostly early-stage hypersensitivity reactions to HD occurring in our department, characterised by malaise, desaturation, bronchospasm and arterial hypotension, with good response to the session’s temporary suspension and with reappearance in subsequent sessions that used a synthetic dialyser. No hypersensitivity reactions reappeared in successive observations when the sessions were carried out using a cellulose membrane.

Terminal chronic renal failure patients show early insulin resistance (IR), characterised by alterations in the hydrocarbon metabolism and hyperinsulinaemia generally associated with dyslipidaemia and a proinflammatory condition. Cardiovascular disease (CVD) is the main cause of mortality in patients on dialysis. There is a strong association between IR, hyperinsulinism and CV disease. The objective of this study was to evaluate the effect of peritoneal dialysis (PD) on IR and its effects on the subsequent CVD morbidity and mortality in nondiabetic uraemic patients. It involved 69 nondiabetic patients on PD, 35 incident patients (≤ 3 months on PD) and 34 prevalent patients (>3 months on PD), with 2 estimated insulin resistance measurements 12 months apart using the insulin resistance index (HOMAIR). The mean HOMAIR value in incident patients was 1.8 ± 1.3 and 2.2 ± 2.1 at baseline situation and at 12 months respectively (not significant [NS]). In prevalent patients these values were 2.3 ± 1.3 and 2.5 ± 2.2 (NS). In our study, the mean glucose, insulin and IR concentrations measured by the HOMAIR and QUICKI indexes (the latter being a quantitative control for insulin sensitivity control) were similar at baseline situation and the following year, in both incident and prevalent patients. We did not find any significant differences in relation to CVD comorbidity, ischaemic heart disease, heart failure or cerebrovascular or peripheral comorbidity neither in the HOMAIR index or insulin levels. To conclude, nondiabetic patients on PD do not display a significant increase in HOMAIR levels and this remains the case over time when on dialysis. This, in turn, suggests that PD is not an IR risk factor. The fact that the IR indexes are not associated with CVD morbidity or mortality seems to suggest that this is a less significant factor in the field of PD.

Bowel bacterial overgrowth syndrome (BBOS) is an important cause of gastrointestinal (GI) abnormalities. Proinflammatory cytokines (PICs) are excessively produced and accumulate because of kidney failure in dialysis patients who experience chronic infections such as BBOS. We explored the association between GL function, BBOS, and the malnutrition, inflammation, and atherosclerosis (MIA) syndrome. We studied GI malabsorption and maldigestion by analyzing fecal starch, sugar, fat, and nitrogen; intestinal protein permeability (alpha1-antitrypsin fecal clearance); and fecal chymotrypsin. We evaluated BBOS by breath hydrogen test (BHT) after a 3-day fat-and-carbohydrate-overload diet. Positive BHT was present in 10 patients, showing a high prevalence of GI macronutrient malabsorption and maldigestion, and compared with the other patients, the highest plasma levels of tumor necrosis factor alpha and interleukin 6 and lower levels of albumin and prealbumin. Those 10 patients were treated with a combination of several antibiotics, including neomycin, amoxicillin-clavulanate, and quinolones. Between 2 and 3 months later, the BHT, markers of nutrition, and PIC were re-tested. All treated patients showed an improvement in nutrition status and a lesser inflammatory pattern. The BBOS infectious process is found frequently in dialysis patients in association with GI malabsorption and maldigestion, malnutrition, and systemic inflammation. Hyperproduction of PIC because of BBOS induces MIA through a double pathway: GI disorders and deleterious systemic effects.