The choice of dialysis modality is affected by both medical and non-medical factors, including patient preference and social and geographic factors. Although the long-term maintenance of dialysis modalities has been realized, evaluation of the risk factors associated with technique survival in dialysis is important when selecting a dialysis modality.

The long-term prognosis of end-stage renal disease (ESRD) patients according to dialysis modality remains controversial. Peritoneal dialysis (PD) is generally associated with a higher survival rate than hemodialysis (HD) in the early period after commencement of dialysis [1-3]. Moreover, PD is associated with greater preservation of residual renal function (RRF) than HD [1,4,5]. However, it also has a considerably higher technique failure rate than HD. The various causes of technique failure in the early stage of PD (i.e., within the first year after its initiation) include infection, catheter dysfunction, peritoneal leaks, or psychosocial problems. Among these, peritonitis is the most common cause of technique failure in the early period of PD. In the later stage, the common causes of technique failure in PD include peritonitis, ultrafiltration (UF) failure, and catheter-related infection [5-7].

In Korea, several retrospective single-center studies of technique survival in PD have been reported [8-12]; however, no comparative reports on technique failure involving multicenter prospective cohorts have appeared. Therefore, to compare technique survival between dialysis modalities and to evaluate the associated factors, we analyzed technique survival in dialysis patients enrolled in the prospective observation cohort at the Clinical Research Center for End-Stage Renal Disease (CRC for ESRD) in Korea.

This study is the first prospective cohort study to compare technique survival according to dialysis modality in Korea. Only dialysis modality was independently associated with technique survival by multivariate analysis after adjusting for baseline characteristics. Moreover, the risk of technique failure of PD was 10-fold higher than that of HD. Similarly, previous studies in other countries reported that HD has a higher technique survival rate. In 2001, NEetherlands COooperative Study on the Adequacy of Dialysis (NECOSAD) reported a higher technique survival rate for HD than PD, and the results were similar to those reported before 2000 [14]. In 2005, a cohort study from the United States reported that the rate of conversion of HD to PD was < 5%, whereas that of conversion of PD to HD was ~25% [15]. In Korea, patients with ESRD secondary to lupus nephritis showed similar results, with the technique survival rate of HD being higher than that of PD [16].

There are prominent characteristic differences between the two modalities, including in terms of modality access. PD catheters could be harmful in cases of severe peritonitis, so early removal may be needed depending on the presence of conditions such as fungal infection, refractory bacterial peritonitis, and encapsulating peritoneal sclerosis [17]. In contrast, vascular access for HD can be repaired repeatedly or recreated on the other side. However, HD patients who have inadequate conditions for maintaining HD such as central vein stenosis, recurrent thrombotic obstruction of vascular access, and severe congestive heart failure might be recommended to switch from HD to PD. In addition, a PD catheter can be reinserted to resume PD after resolution of severe peritoneal infection. Cases in which PD was restarted within 60 days after PD catheter removal were not counted as technique failures in our study. Although the characteristics of technique survival differed between PD and HD, both modalities could be discontinued due to various clinical conditions. Studies have compared technique survival rates between the two modalities because analysis of associated risk factors is necessary to improve the technique survival rate in dialysis patients.

The causes of technique failure in PD include peritonitis, patient preference, inadequate dialysis, and surgery. Among these causes, peritonitis most commonly results in technique failure. In the present study, UF failure was not the main cause of technique failure, possibly because the study was conducted within 2 years of initiation of PD. In a previous study from the UK, the most common cause of technique failure in PD was reported to be peritonitis, followed by poor dialysis, failed peritoneal access, wish to transfer to HD, complications of high intra-peritoneal pressure, poor UF, and cessation of dialysis [7]. Thus, our study confirms the previously reported finding that peritonitis is a leading cause of technique failure in PD. In the United States, the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study reported infections as the leading reason for transferring from PD to HD, followed by cardiovascular factors (fluid overload) and abdominal surgery, pancreatitis/malnutrition, decreased mental capacity, and abdominal wall defect [18]. On the other hand, the Australia & New Zealand Dialysis & Transplantation (ANZDATA) registry reported social reasons as the most common primary cause of technique failure in PD, followed by infection, mechanical/technical complications, and dialysis failure [19]. In many Asian countries, peritonitis was the most common cause of technique failure in PD [11,20,21]. In Spain, peritonitis was the main reason for transfer to HD from PD, followed by UF problems, insufficient dialysis or problems related to the peritoneal catheter [22]. Thus, peritonitis remains the most common cause of technique failure in PD in most developing countries and some developed countries; however, in other countries, it has been replaced by social reasons.

BMI was the only independent risk factor for technique failure in PD in the present 2-year follow-up study. We additionally analyzed the data regarding the number of peritonitis cases in two BMI groups, dichotomized by the median BMI value. In the high BMI group, four of seven cases (57.14%) of technique failure were attributed to peritonitis, compared to three of four patients (75.00%) in the low BMI group. The difference was not statistically significant because of the low number of events. Therefore, whether technique failure in the high BMI group could be attributed to the higher incidence of peritonitis remains unknown. In a combined cohort study involving Chinese and Canadian centers during a 5-year follow-up that commenced in 2000, BMI, albumin, and female gender in the Chinese centers were independent predictors of technique failure in PD [21]. In Pakistan, an 18-year follow-up study that commenced in 1995 reported that BMI was the only factor significantly associated with technique survival, on the basis of a univariate analysis. However, in India, a study of BMI and PD outcomes involving four BMI groups (obese, overweight, normal, and underweight) reported that all of the BMI categories showed a similar technique survival rate with PD, with obese patients having a greater risk of peritonitis [23]. On the basis of these results, we analyzed the difference in technique survival rates between dialysis modalities according to BMI category. Patients with a higher BMI had higher technique survival when HD was used as the dialysis modality.

To determine the specific factors that resulted in the difference in technique survival between dialysis modalities, we divided the two groups according to the presence of diabetes and malnutrition. The difference in technique survival between dialysis modalities was more prominent in diabetic patients with a good nutritional status and non-diabetic patients with malnutrition. These findings suggest that the technique survival rate would be higher with HD rather than PD in diabetic or malnourished patients. In general, diabetic PD patients have a higher technique failure rate [24-26]. Previous studies have suggested that poor glycemic control is associated with a higher technique failure rate in PD patients [26,27]. The effect of glycemic control using non-glucose-based PD fluid on technique survival should be investigated in future studies. The use of icodextrin-containing solutions in diabetic PD patients enhances the technique survival rate. However, this beneficial effect was attributed to improved control of body fluid status rather than good glycemic control [28]. Therefore, use of PD in diabetics should be decided on an individual-patient basis. Several reports on the relationship between nutrition and technique failure in PD patients have been published [6,10,29,30]. Serum albumin, lean body mass, and SGA had positive relationships with technique survival rate. A Chinese study reported that an increase in lean body mass reduced the HR for technique failure in PD [29]. The Canada-USA (CANUSA) study reported that a decreased serum albumin concentration was associated with an increased risk of technique failure; however, other estimates of nutrition (normalized protein catabolic rate, SGA, lean body mass) were not associated with technique failure [30]. Kwon et al. [31] reported that serum albumin had a significant effect on the technique survival rate of Korean PD patients. In this study, the nutritional status was assessed by SGA, and the results confirmed that patients with a poor nutritional status have lower technique survival rates with PD than in HD.

The limitations of this study were the small number of patients with technique failure and the short follow-up period. In addition, we did not analyze the direct association between BMI and peritonitis, or between diabetic control or nutritional status and technique failure. Thus, additional long-term follow-up studies of the technique survival rates of dialysis modalities that investigate the associations between technique failure and various risk factors are warranted.

In summary, dialysis modality was the only independent risk factor predictive of technique survival in incident dialysis patients. The findings of this multicenter, prospective cohort study conducted in Korea confirms that the technique failure rate of PD is higher than that of HD during the early period of dialysis treatment. In addition, BMI was the only independent risk factor for technique failure using the early period of PD. The difference in technique failure rate between the HD and PD groups was more prominent in patients with a higher BMI and diabetic patients with a good nutritional status, as well as in non-diabetic patients with a poor nutritional status.