| Peritoneal dialysis is one of the most common forms of renal replacement therapy for the end-stage kidney disease(ESRD) patients. More and more patients choose peritoneal dialysis for the advantages of maintaining residual renal function,good middle molecular toxins clearance and saving medical resources. Previous studies have found that considerable progress has been made during the past decade in the practice and management of peritoneal dialysis. However, cardiovascular events, malnutrition, complications such as peritonitis is still prevalent, which play an import adverse role of the survival rate and quality of life in peritoneal patients. Therefore, how to reduce the peritoneal dialysis complications is still one of the urgent subject facing renal physicians.Peritonitis is one of the serious complications of peritoneal dialysis patients. These infections are significant cause of morbidity and technique failure, with dropout to hemodialysis(HD) among patients undergoing peritoneal dialysis by affecting the peritoneal membrane ultrafiltration failure [1]. The study of peritonitis etiology, treatment and prognosis has been the hot topics of peritoneal dialysis research at home and abroad. In order to reduce the peritoneal dialysis related peritonitis mortality and peritonitis-related serious consequences, it is important to identify the risk factors and vulnerable population for peritonitis. Studies have shown that the elderly, women, blacks or Maori, obesity, low education level, diabetes, hypoalbuminemia, and decreased residual renal function are independent risks factors of peritonitis [2-5]. But more system research are warranted.Malnutrition is an important factor influencing mortality of peritoneal dialysis patients as well. A syndrome of adverse changes in nutrition metabolism and body composition is highly prevalent in patients with chronic kidney disease, particularly in those undergoing dialysis. According to the recent studies, Malnutrition contributes to the high mortality and hospitalization rate of PD patients. It has been shown in PD patients that malnutrition is closely related to the higher mortality [2].Mehrotra's study shown that PD patients with low serum albumin levels had higer all-cause death and cardiovascular mortality and infection related mortality [7]. This study uncovered the underlying relationship peritonitis with the nutrition status in PD patients, but the results need validation in different population groups. Meantime, albumin is an important facor of the PEW and a serum albumin level of less than 3.8 g/d L is one of the recommended diagnostic criteria of the PEW. It can be speculated that malnutrition plays an important role in the process of peritonitis. In addition, BMI and body weight are also important nutrition index. However, the relationship between BMI /weight and peritonitis remains controversial at present. Studies of the relationship between BMI /weight and peritonitis are less reported. And few studies has been focused on these indicators and their combination forecast of the peritonitis in peritoneal dialysi so far.There are many nutrition evaluation method applied to the chronic dialysis patients in Clinical common progress. in addition to the serum albumin mentioned above, BMI and weight, biochemical examination, nutritional assessment scale and anthropometry indicators are the most common indicators of nutrition status. According to the different assessment method, 6%- 10% of dialysis patients had serious malnutrition, up to 30%- 35% mild to moderate malnutrition [4]. Moreover, the inflammatory factors will also affect the nutritional status. Uremia patients usually have a moderately elevated inflammatory factor levels in the body, called microinflammatory state. Inflammation malnutrition and arthrosclerosis often exist at the same time. Some scholars recommend malnutrition-inflammation- arthrosclerosis syndrome to understand the relationship between these three factors. Nutritional assessment methods above are common in clinical practice, but each has advantages and disadvantages. However, which is the most efficient indicator for PEW and clinical prognosis of malnutritional PD patients is still unclear. Few studies can answer the question. We still need further research to help us to understand the nutrion issues in peritoneal dialysis patients and guide clinical treatment options.Uremia patients have a moderately elevated inflammatory factor levels.Inflammation,malnutrition and atherosclerosis often exist at the same time and influence each other. IL-6 is typical cytokine exhibiting functional pleiotropy.IL-6 is involved in immune response, inflammation. Mononuclear cells, fibroblast cells, endothelial cells and other types of cells can synthesize and secrete IL- 6 [5]. Several studies in PD patients found that IL-6, CRP and other inflammatory cytokines were associated with serum albumin levels. In HD patients, high IL-6 was associated with hypoalbuminemia and hypercholesterolemia, which were two common indicators of malnutrition [6]. Association between IL- 6 and anthropometry index, such as nutrition scale and anthropometry are rarely studied. Recent studies have shown that there are some promoter polymorphisms in the IL-6 gene. Some polymorphisms involving the 5-flanking region(promoter) of the IL-6 can affect the gene transcription and expression. In addition, these single nucleotide polymorphisms(SNPs) may significantly influence the immune response, the levels of inflammatory markers and as well as the progress of diseases. rs1800796(- 572- C/G) is one of the promoter polymorphisms. Some studies have shown rs1800796 influenced body composition and biochemical markers, but the relationship are not clearly yet.The first part of this study we retrospectively analyzed the clinical characteristics and risk factors which influence the risk of dialysis-related peritonitis complication in stable peritoneal dialysis patients in Shanghai Jiaotong University school of medicine affiliated Ruijin hospital. PD patients without peritonitis episode ever usually had a short duration on PD, a young initial dialysis age and no diabetes(P < 0.05). Patients who ever had a peritonitis episode had lower 24- h urine albumin, serum albumin levels and higher blood glucose concentration than those without peritonitis episodes. In the fully adjusted Cox proportional hazards model, there were five baseline variables with a significant independent effect on the risk of peritonitis. These included: age [HR = 1.01(1.0007–1.02)], serum albumin [HR = 0.58(0.44–0.76)], weight [HR = 1.02(1.01–1.04)], and blood calcium [HR = 1.97(1.15–3.37)] and 24hour-Urine volume [HR = 0.97(0.95–0.99)]. Based on these observations, we developed a 5-variable equation of a clinical risk score for peritonitis risk. With one score increase in risk factors the incidence of peritonitis increased 2.72 fold. Pathogenic analysis shows that different pathogenic bacteria peritonitis has different clinical outcomes. Fungal peritonitis is rare but it had a high technical failure rate. In conclusion, we have a primary understanding of the peritonitis related risk factors and relationship between the nutritional statuses of peritoneal-related peritonitis. thus nutrition is an important factors related to the peritonitis. Improving nutrition status helps reduce peritonitis risk and finally improve clinical outcomes of peritoneal dialysis patients.The second part of this study, we discussed the different nutritional assessment methods applied in PD patients and the association of IL-6 and one of its ingle nucleotide polymorphisms-rs180096 with the nutrition status in PD patients. We recruited stable dialysis patient of Ruijin hospital peritoneal dialysis center. All the enrolled PD patients underwent Malnutrition-inflammation score assessment and their body composition was measured by bioelectrical impedance technology at the same time of MIS score. Biochemical markers were measured. We found that the malnutrition(defined by a MIS score higher than 9) rate of PD patients was 23.7%. Compared with patients with malnutrition group, well-nourished patients were younger and had shorter dialysis duration and have a higher mean arterial pressure and better biochemical markers such as albumin, hemoglobin, cholesterol, transferrin, 24 h urine volume than malnutrition group. Comparing the BIA indices, we found well-nourished patients have high weight, BMI, body fat mass, FFM, mineral content, protein mass, ICW and ECW, BF% and BMC. Edema index and ECM/BCM is lower in well-nourished patients.Malnutrition patients had a higher level of inflammation factors(IL- 6 and hs-CRP), and MIS is positively correlated with inflammation. Multiple regression analysis showed that age, hs – CRP, ECM/BCM are independent risk factors for MIS. After adjusted for age, sex and BMI, hs–CRP, ECM/BCM are independent risk factors for albumin. Therefore, MIS score is highly related with age, inflammation index(IL-6 and hs-CRP), 24 h urine volume, transferrin and bioelectrical impedance index(ECM/BCM) and were can be used for PD patients nutrition assessment. In addition,our study showed that there was no association of rs1800796 genotypes and IL-6 levels. Compared with CC group, mineral content is higher group patients. Fat-free mass, body cell mass, protein, skeletal muscle mass and other BIA indicators have a non-statistically significant increase in the CG /GG group. BIA indices offer the information of body composition and are an important part of nutrition assessment.In conclusion, we recruited a large group of PD patients and by analyzing basic information and laboratory biochemical markers and nutritional markers such as urine volume, BMI,we found that age, weight, serum calcium and albumin, urine volume are independent predicting factors of the peritonitis. Based on these observations, we developed a 5-variable equation of a clinical risk score for peritonitis risk. With the above systematic study of effect of nutritional status on peritonitis risk in PD patients, we have a primary understanding of the effect of nutrition related factors on peritonitis risk. Nutrition is closely related to the risk of peritonitis and clinical practice improving nutrition status will help reduce peritonitis rate and finally improve peritonitis prognosis. Further assessment of the common method for nutritional evaluating, we found that MIS score can be used for PD patient's nutrition assessment. BIA indices offer the information of body composition and BIA indices have a good relation with biochemical markers, inflammation markers and MIS score. BIA are an important part of nutrition assessment. This study suggests that there is no single golden indicator for the present practice in nutrition assessment in PD patients. We still need to be combine several assessment methods such as clinical assessment, laboratory markers and bioelectrical impedance analysis to fully evaluate the nutritional status. MIS scale is the good and convenient method in the evaluation of clinical nutrition. IL- 6 as a major inflammation factor, its gene polymorphisms have potential value for evaluating PD patients nutrition status. |
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