Patient-reported advantages and disadvantages of peritoneal dialysis: results from the PDOPPS

In the United States (US), changes in dialysis reimbursement policies have led to unprecedented growth in the use of peritoneal dialysis (PD) since 2011 [1]. Compared with facility hemodialysis (HD), PD is more cost-effective [2, 3], is less technically demanding [4], minimizes the exposure of patients to hospital-acquired infections [5], is more feasible in rural and remote settings [6], and is associated with better preservation of residual kidney function [7, 8] – a factor associated with survival advantage among patients receiving dialysis [9‐12]. Commonly perceived patient advantages of PD include enhanced opportunities for rehabilitation and return to employment and improved satisfaction and quality of life (QOL) [13]. Studies have suggested that reasons patients select PD include less interference with lifestyle, preference to be independent, wanting to dialyze at night, and less requirement for travel for dialysis treatments [13, 14]. However, patients also view disadvantages to PD therapy, including “catheter care,” “high frequency of dialysis in a day,” and “troubling other people” [15]. Negative aspects of PD have been cited as “problem with supplies,” “frequency/length of treatment,” “bloating/pain,” “interference with sleep,” and “change in daily routine” [16].

To help patients make an informed decision about whether to pursue PD, nephrologists and other health educators typically explain presumptive advantages and disadvantages of this dialysis modality. However, there is little insight into how patients performing PD typically rate these potential advantages and disadvantages and to what extent they impact overall satisfaction with PD therapy and clinical outcomes. Therefore, a better understanding of what patients like and dislike about their PD therapy may help inform those faced with a dialysis modality decision and help prioritize strategies to improve the PD patient experience, thereby potentially increasing PD uptake and extending technique survival.

Based on responses to a standardized patient questionnaire (PQ), we analyzed data from the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) to investigate: 1) patients’ perspectives of PD, including what they consider to be advantages and disadvantages of therapy; and 2) how patient outcomes differed based on their views regarding PD therapy.

In this large, international study evaluating patient perceptions of PD, there were four principal findings. First, PDOPPS patients in all countries reported many more advantages of PD than disadvantages, with a median ADS of 0.76. Second, we found that patients with an overall negative perception of PD were more likely than patients with a positive perception to transfer to HD. Third, among individual components of the ADS, we found that the two most frequently reported disadvantages were “feeling full with PD fluid in abdomen” and “space taken up by PD supplies”; however, only the latter perceived disadvantage was also associated with transfer to HD. Fourth, patients with more negative perceptions of PD were more likely to have worse QOL scores and more depressive symptoms.

In a study validating the Customer Satisfaction Questionnaire developed by Fresenius Medical Care, the composite satisfaction score was found to be a good overall measure of patient satisfaction in PD care, but associations of subscale domains with the total score suggested that efforts focused on improving specific aspects might be more effective in increasing patient satisfaction [24]. Hence, we evaluated individual components of the ADS and found that “impact or burden on family,” “maintain or apply for job,” and “space taken up by PD supplies” were associated with transfer to HD. While the opportunity for employment continues to be a perceived advantage of PD (compared with HD), patients may view “maintain or apply for a job” as a disadvantage if they are comparing this with employment prior to starting dialysis (vs. what employment while on HD was or would be like), or perhaps if the ability to “maintain or apply for a job” did not live up to their expectations of the freedom they were counseled to expect with PD. While the loss of employment has been shown to be similar after initiation of HD or PD [25], studies have also shown a significantly higher loss of employment with HD, compared with PD [26]. However, any type of dialysis is likely to be somewhat restrictive, and the benefit of maintaining or applying for a job while on PD may be more of a theoretical advantage. “Space taken up by PD supplies” was the second most commonly rated disadvantage, underscoring the impact of the space required to store PD supplies. Lack of space at home is a frequently-reported barrier among prevalent HD patients when even simply considering home dialysis [27]. While we did not suspect an association of “space taken up by PD supplies” with mortality, we did hypothesize the association with transfer to HD, given that the outcome of transfer to HD is generally more likely to be patient-driven, compared with the outcome of mortality.

It is reasonable to assume that patients are more likely to view this storage space aspect negatively if their living space is small, especially if they have to share their living space. The average residential floor space per capita in the UK is 356 square feet (33.1 m²) versus 832 square feet (77.3 m²) in the US [28], and likely accounts, in part, for the higher percentage of patients in the UK who viewed “space taken up by PD supplies” as a disadvantage than in the US (Additional file 2: Figure S1). Patients with larger prescribed fluid volumes were more likely to view “space taken up by PD supplies” as a disadvantage (Additional file 1: Table S2), and strategies that minimize total PD fluid needs may be advantageous. However, it is essential that patient care not be compromised by reducing treatment volumes or omitting day-time dwells in an attempt to decrease total PD fluid needs, as this may lead to inadequate dialysis with impaired sodium (and thereby fluid) removal and inadequate middle molecule clearance. While lower dialysate dwell volumes could potentially be advantageous in the new patient, using incrementally larger volumes as needed with the decline of residual kidney function over time, another strategy could be more frequent delivery of supplies, which would reduce the number of boxes in the home at any one time, thereby minimizing the space required for storage without reducing the fluid prescription. Additionally, there is likely to be an emotional component related to viewing “space taken up by PD supplies” as a disadvantage, since the large boxes that occupy space in the home possibly serve as a reminder to the patient that they are living with a chronic disease. Novel technologies may soon enable patients to create dialysate fluid on-site, thereby reducing storage requirements. Future studies will be needed to evaluate whether and to what extent reducing the burden of solution storage may minimize negative perceptions of PD and, therefore, possibly prolong PD technique survival.

Patients with a less favorable perception of PD were younger, had a lower BMI, and had lower 24-h urine volumes (Table 1). Patients with lower BMIs may be more sensitive to their dwell volumes, possibly feeling full more easily, and, therefore, may view PD more negatively. Additionally, those with lower 24-h urine volumes may try to achieve greater peritoneal ultrafiltration with greater fill volumes, thereby further contributing to a feeling of fullness. We found that patients using APD tended to view PD more positively than those using CAPD, similar to previous findings [29]. Patients using APD accomplish the majority of their therapy at night while sleeping, allowing more flexibility with their time during the day. Similarly, we found those with a “day dwell” viewed PD more negatively, as the effect of gravity while patients are upright likely causes more discomfort. The lowest ADS category had a higher percentage of patients who required help setting up and performing PD treatments; this supports previous reports, whereby PD patients commonly listed “troubling other people” as a main disadvantage of PD [15].

In the analysis of PROs, lower ADS scores – suggesting a more negative perception of PD – were associated with lower scores of physical and mental health and increased symptoms of depression. It is possible that the direction of this association may be such that the negative perception of PD led to inferior QOL and greater depression. Equally plausible is that this association may be the result of patients with impaired QOL and depression at baseline, which impacted their perception of PD. Previous studies have demonstrated an independent association between depression and increased mortality risk in dialysis patients [30], as well as an independent association between depression and peritonitis rates [31], which is a common cause of transfer to HD [32].

This study should be viewed in the context of the following limitations. First, given the observational study design, we cannot rule out residual confounding due to unmeasured risk factors or model misspecification. For example, we did not collect information on the sizes and locations of patients’ homes, which may have explained some of our findings. Second, as previously mentioned, since the analyses between ADS and the PROs of MCS, PCS, and CES-D scores were cross-sectional, the possibility of reverse causation limits the ability to assume a causal relationship. Third, the cross-sectional analyses are also susceptible to selection bias because the survey outcomes could have influenced the selection of subjects, which is especially true in this study, given that the survey response rate was only slightly better than 50%. However, as shown in Additional file 1: Table S1, there were no large differences between survey respondents and non-respondents. Fourth, the high proportion of PD patients reporting favorable views of PD might have been exaggerated due to the possible tendency of patients to answer those survey questions in ways they thought were expected or desired by the investigators. Finally, while most validated questionnaires currently assess QOL among PD patients, one validated survey assigns priority to aspects of the dialysis patient experience based on patient responses, but only a single aspect relates to PD specifically: “immediate help in case of peritonitis” [33]. Although the survey questions of our 17-item questionnaire were generated based on expert consensus, many of the items overlap with what long-term PD patients have identified as reasons for choosing PD [34]. However, while little prior literature or psychometrics informed the content of our survey, this will serve as a stepping stone for future work in developing a validated questionnaire, using more patient engagement, to meaningfully assess the balance between patient-perceived PD advantages and disadvantages.

This is the largest study to-date to include PROs on PD patients, and we found associations between an overall negative perception of PD therapy and a higher rate of transferring to HD, worse QOL scores, and more depressive symptoms. Moreover, patients who viewed “space taken up by PD supplies” as a disadvantage had a higher rate of transferring to HD. Our findings will assist nephrologists and members of the end-stage kidney disease (ESKD) care team to better provide more informed counseling with quantifiable advantages and disadvantages to patients considering PD as their dialysis modality. Additionally, given the possible influence of reverse causation in the cross-sectional findings of this paper, not only could improving the perceived disadvantages of therapy improve QOL and depression, but efforts directed at enhancing support for patients’ physical and mental well-being and improving depression symptoms may help improve patients’ perceptions of PD therapy. Future studies are needed to determine the extent to which the expected advantages and disadvantages of PD in pre-ESKD patients are similar to the perceptions of those patients after starting PD, as this will allow for more accurate and personalized counseling of ESKD patients considering PD. Finally, given that “space taken up by PD supplies” is a commonly perceived disadvantage, and that this perception is associated with an increased likelihood of transferring to HD, modifying therapy with new technologies, such as on-site PD fluid creation, may positively affect the patient’s experience and is worth further investigation.