In this retrospective cohort study, we analyzed the incidence and risk factors of the technique failure in the first year of PD on 2,290 incident PD patients. Overall, the incidence of technique failure within the first year after the start of PD was 7.5%. The rate of technique failure due to death was 4.7% and due to transferring to HD was 2.8%. The main causes of early death were cardiovascular diseases and infectious diseases, while the main causes of early transfer to HD were mechanical failure and infection. Advanced age, lower BMI, history of HD or congestive heart failure and peritonitis, were the factors associated with increased risk, while using employee medical insurance to pay expenses and high serum albumin associated with decreased risk for the technique failure.
In a study involving more than 30,000 patients in the United States, the rate of transferring to HD during 1 year reached 18.7%-20.5% [10]. ANZDATA Study on 16,748 PD patients reported that 4,389 patients (26.2%) developed early technique failure (including death and transferring to HD) during the first year of PD therapy. In a study of Singapore, 19% of patients developed to technique failure (including death and transferring to HD) in first year after PD start[11]. A retrospective cohort study of 5,162 PD patients in Canadian showed that the 1-year conversion rate to HD was 12.7%[12]. In current study, the technique failure rate within the first year of PD in our center was 7.5%. The relative low incidence of technique failure in the early stage of PD may attribute to the Asian race, younger cohort, less comorbidity and larger PD center size[13, 14]. More than 1,000 PD patients have been followed up by a well-trained PD team in our center since 2012. A unique therapy and management approach that includes a standardized procedure for catheter insertion, a carefully designed PD prescription, a meticulous and comprehensive patient training and follow-up care may involve in the lower technique failure rate [15].
We found that death was the leading cause of the technique failure. Among the 173 cases of technique failure occurred in the first year of PD, death account for 62.4%. In a Dutch study, deaths accounted for 69% of the total number of early technique failures[16]. Studies in South Korea, Singapore and Canada also demonstrated that death was the leading cause of early withdrawal from PD[11, 12, 17]. In our study, cardiovascular (CV) death was the leading cause of death (29.6%). We found that a baseline history of congestive heart failure was also a risk factor for death and technique failure. According to recent reports, patients with volume overload at the baseline have a higher risk of death and conversion to HD over the next 12 months[18]. The early history of heart failure often indicates poor volume control, poor residual renal function and cardiac function, insufficient ultrafiltration and peritoneal permeability, and poor effect of PD model or treatment prescription[19–21]. The control and monitoring of the patient volume and the maintenance of the patient's fluid balance are very important for the patient's technical survival. According to our previous report, about 86.5% of the catheter function problems occurred in the first year of PD [22]. In current study, the results showed that transferring to HD due to mechanical problem accounted 16.2%, of which 64.0% occurred in the first six months. RDPLF study revealed that catheter dysfunction accounted for 18.1% of the early conversion to HD [5]. In ANZDATA study, mechanical causes accounted for 19.7% of the early technique failure (including death and transferring to HD) [3]. All these studies have similar results which indicated mechanical problem played an important role in the technique failure due to the transferring to HD during the early stage of PD.
Our previous study demonstrated that early peritonitis was a risk factor for early death-censored technique failure [23]. The current study also demonstrated that peritonitis was not only a cause but also a risk factor associated with technique failure during the first year of PD [24]. ANZDATA reported that the incidence of direct conversion to HD in new PD patients due to peritonitis within the first 12 months was high as 16.4% [25]. RDPLF study also showed that patients with early peritonitis had a 53% increased risk of transferring to HD [26]. A South Africa cohort revealed that the risk of technique failure in patients with more than one attack of peritonitis increased by 90% [27]. In addition, studies have shown that peritonitis was also associated with an increased risk of all-cause death in PD patients[28, 29]. Recent study in our center found that the impact of peritonitis on mortality was more significant in patients with longer PD duration [30]. However, there was no direct evidence that peritonitis increased the risk of death in the early stage of PD.
The current study revealed that elderly patients was significantly associated with technique failure, in particularly, the death, but not with transferring to HD in the first year of PD. ANZDATA's study demonstrated that age > 70 was an independent risk factor for early technique failure (including death) in PD, with a 43% higher risk compared to younger PD patients [3]. It has been documented that history of HD is a risk factor for technique failure in previous studies [3, 5, 12]. Here we also demonstrated that patients with a previous history of HD had an increased risk of early technique failure. In addition, our study found that PD patients with complete self-care have a lower risk of death during the first year of PD. McGill, et al reported that the risk of death of working patients decreased by 18%, the risk of conversion to HD decreased by 27% [31]. Patients with old age, previous history of HD or frailty have the problems that may affect their compliance to PD treatment and therefore affect their prognosis [32]. Attention should be paid for the special population to reduce the technique failure in the early stage of PD.
Both a lower albumin levels and BMI reflect malnutrition. It was well documented that hypoproteinemia was associated with an increased risk of deaths as well as peritonitis [33]. Our previous study demonstrated that patients with serum albumin < 3.5g/dL had a 75% increased risk of peritonitis[23]. A study from the Middle East found that a dynamic decrease in serum albumin in PD patients indicated an increased risk of transferring to HD [34]. The current results further demonstrated that lower serum albumin was associated with early death and technique failure. ANZDATA's study revealed that lower BMI (< 18.5kg/m2) increases the risk of early technique failure compared with BMI (18.5-30kg/m2) in the first-year of PD [3]. However, higher BMI in the study of Jaar et al was reported to be associated with the risk of early transferring to HD[35]. Our study showed that low BMI were associated with early technique failure, and that low BMI was significantly associated with death.
We did not find the relationship between diabetes and early technique failure. Previous studies have shown that diabetes significantly increased the risk of technique failure [13, 16]. ANZDATA have found that diabetes was risk factor for technique failure within one year [3]. Previous studies on patients who withdrew from PD (including death, HD and renal transplantation) within an ultra-early stage (3 months) did not find that diabetes was associated with the drop-out from PD [36]. The effect of education levels on early technique failure was unclear. A study from South Korea reported that patients in junior high school and below were associated with early technique failure [37]. Chidambaram's study found that the level of education in the place of residence is related to the risk of early technique failure [12]. However, we did not demonstrate the effect of education level on early technique failure. In a national study in South Korea, patients who participated in comprehensive health insurance had a relatively low risk of technique failure [17]. In addition, our study revealed that patients with employee medical insurance had a lower risk of death and transfer to HD than patients with resident medical insurance, which is related to the fact that patients with employee health insurance tend to have more stable and higher-paying jobs. Patients who participate in employee medical insurance tend to have a higher proportion and amount of reimbursement than resident medical insurance. we think that the type of medical insurance could better represent the social and economic status of patients than their income situation.
Our current investigation has several limitations. First of all, this is a retrospective cohort study that the evidence of causality is not strong. Secondly, due to the large time span of this study, many covariates were not included in the analysis, such as peritoneal function, catheter selection and operation, psychological status, subjective indicators of patients and doctors, and so on. In addition, due to the limitations of the level of economic development, China's APD and icodextrin are still not widely available and therefore are not included in the analysis. Third, factors related to the characteristics of the center are not included in this single-center study, such as PD prescription habits, anti-infective regimen, center size, etc. It is worth noting that we identified the risk factors associated with technique failure during the first year of PD based on demographic and laboratory data, which were not available in previous studies.
In summary, this retrospective cohort study on 2,290 incident PD patients in Southern China revealed incidence of technique failure within the first year of PD was 7.5%. Advanced age, low BMI, history of congestive heart failure or HD and peritonitis were the factors associated with increased risk, while use employee medical insurance and higher serum albumin associated with decreased risk for the technique failure. Identification of the causes and risk factors may be helpful for the PD center to improve its medical plan and reduce incidence of the technique failure in the early stage of PD. Further studies are needed to clarify the underlying mechanism.