With the aging of the population, spiraling rates of end stage renal failure have increased and the elderly needing for PD is gradually increasing [9]. In order to improve the prognosis and quality of life in elderly patients with PD, it is especially important to explore the survival status of elderly patients and actively prevent and control the risk factors.
We analyzed the general condition of the elderly patients, the reasons for withdrawal from PD therapy, and the risk factors for survival of patients, to provide guidance for improving prognosis and prolonging the survival time of patients on PD with ESRD.
Compared with the younger group, elderly group of PD patients tended to have hypoalbuminemia and low nPCR, both of which are important indicators to evaluate the nutrition of patients [10], this result was consistent with the Kholshali et al study [11]. Wang XX et al also reported that serum albumin remained lower in elderly patients [12]. In the course of PD treatment, a large number of nutrients are lost in dialysis soution, and the absorption capacity of gastrointestinal function is decreased in elderly patients, leading to malnutrition. Peritoneal dialysis does not need to establish vascular access, has little impact on hemodynamics, so elderly patients with diabetes tend to choose PD. Arteriosclerosis and the incidence of cardiovascular 、cerebrovascular events is often occurred in diabetic nephropathy [13, 14]. Age is also a risk factor of vascular calcification [15]. Some studies have shown that elderly PD patients are inclined to develop peritonitis [16], but there was no difference in the incidence of peritonitis between elderly and younger group in this study, which was consistent with a Canada study.It was reported that elderly PD patients who were 70 years old or more had no relationship with peritonitis [17], considering that elderly patients had better family 、social support and was treated with advanced antibiotics.
In this study, the mortality of elderly patients with PD was significantly lower than that of younger patients.Age is a risk factor for survival of PD patients [4, 18]. The 1、2、3、4 year survival rates of elderly PD patients were as follows: 81.97%, 70.49%, 60.66%, 55.74% .A study in China found that the 1 -, 3 -, and 5-year mortality of elderly patients with PD respectively were 79%, 56% and 30% [19], which is generally consistent with our results. Cardiovascular disease is the leading cause of death, 53.4% of elderly PD patients existed with cardiovascular complications in a retrospective study [19]. The USRDS data showed that cardiovascular events were the main cause of death in dialysis patients [20], which was related with the metabolic abnormalities and the increased incidence of diabetic nephropathy in elderly PD patients.
In this study,we provided evidence that high BMI, high CCI and IHD were independent risk factors for predicting death in elderly PD patients. Patients with high BMI is inclined to have high risk of dialysis [21], and obesity can increase cardiovascular and cerebrovascular events, thus increasing the risk of death [22]. However, the relationship between BMI and survival in elderly patients with PD is controversial. Some studies found that obese PD patients lived longer than those with lower BMI [23, 24],considering that patients with lower BMI will increase protein consumption and inflammation, and high BMI can increase hemodynamic stability and the isolation of fat tissue from toxins [25]. Another study found that baseline BMI was not related to the prognosis of peritoneal dialysis [26], so more studies are needed to explore the relationship between BMI and death in elderly PD patients. As mentioned, CCI is an important index to evaluate the complications. Sandrine genestier et al showed that CCI was positively correlated with the mortality of elderly patients [27]. A retrospective analysis of 292 patients found that 2-year survival rate of elderly patients with CCI score > 9 was 38%, and that of patients with CCI < 7 reached 69% [28]. Elderly PD patients often suffer with IHD, and the risk of recurrence with cardiovascular and cerebrovascular events increases [29],so elderly PD patients are at high risk of death.
In this study, peritonitis was main cause of transferring to hemodialysis in both elderly and younger patients. Minli et al. [30] and Sakaci et al. [31] also found that the main cause of turning to hemodialysis was peritonitis. Elderly patients turning to hemodialysis was smaller than that of younger patients. Elderly patients had a higher risk of peritonitis-related and all-cause mortality. In a recent study from Brazil, the only factor associated with death during peritoneal infection was older age [32],so elderly patients had no chance to transfer to HD.
This study elucidated the characteristics of elderly PD patients, the prognosis of elderly PD patients and the risk factors for predicting death, which help nephrologists better understand the characteristics of elderly PD patients and improve the prognosis of patients. However, this study has some limitations. First of all, this study is a single center, relatively small sample study, which can not represent the situation of elderly PD patients in China, additional multiple studies are needed in larger populations to confirm the conclusion of our study. In addition, we did not analyze economic and social situation of each patient.