Peritoneal dialysis (PD) is associated with improved quality of life, is cost effective, and has outcomes comparable with those of hemodialysis (HD). Despite this, there is a big discrepancy in the percentage of US patients using PD: 10.1% versus HD at 89.9% (1). One reason for this difference is likely the number of myths surrounding appropriate PD candidates. These myths are often based on tradition or authority as opposed to evidence. Ready acceptance of such beliefs without re-examining them can lead to improper care. A myth we noted in a previous article in this series is the negligible mortality difference between HD and PD. This month, our post will focus on candidacy for PD and the circumstances in which it is believed to be inferior or inadvisable (2).
Myth 1: PD is not a good option for patients with diabetes
Concerns over hyperglycemia and peritoneal dextrose absorption are not unfounded; however, studies comparing the outcomes in diabetic patients using both dialysis modalities have not consistently shown a superior modality. In 2015, the European Renal Best Practice Diabetes Guideline Development Group published a systematic review of 25 observational studies of patient survival by modality. The authors found that patient outcomes were inconsistent; no mortality differences were detected in an intention-to-treat analysis across subpopulations and follow-up periods. There was a significant heterogeneity in study design and in outcomes among studies, leaving the authors to find that no conclusion could be made regarding mortality (3). In the absence of a clear superior dialysis type, modality selection should be based on patient preference. Care should be taken to avoid hypertonic dextrose solutions, given their higher glucose content; however, this is not a contraindication to the modality. A multidisciplinary approach to the management of diabetes and hyperglycemia is recommended.
Myth 2: PD is not a good option in obese patients
A second misconception is that body habitus may preclude the use of traditional exit sites. Presternal exit sites are good options for obese patients who are motivated to use PD. Although the implantation technique is more difficult, the disadvantages in comparison with a traditional catheter are minimal (4).
Another common misconception is that adequate dialysis is difficult to achieve in obese patients. First and foremost, it should be noted that the conventional methods of evaluating adequacy are not reliable in obese patients. Adequacy, or Kt/V (whereby K is the clearance of urea, t is time with dialysis, and V is volume of distribution of urea), is unlikely to be accurate in obese patients because the V calculation does not account for the lack of significant urea content of fat, owing to the low water content. Inasmuch as the volume of distribution of urea is total body water, and the Watson equation estimates total body water from height, weight, sex, and age, miscalculations of total body water based on assumptions about body habitus from total body weight can cause miscalculations of Kt/V. Despite that, in cases where Kt/V is used to calculate adequacy in obese patients, clearance can be obtained (2). Furthermore, a retrospective cohort study found that overweight and obese patients using PD survived longer than did those with lower body mass index, even after adjustment for transplantation and modality failure (5). Regardless, dialysis should be individually based; it should be provided for symptomatic relief and should not be based on arbitrary numbers. This sentiment is also shared by the latest recommendations from the International Society for Peritoneal Dialysis, in which its guideline released in February 2020 endorses a more personalized approach to PD patients as opposed to a one-size-fits-all approach.
Myth 3: PD is not a good option for patients with autosomal-dominant polycystic kidney disease (ADPKD)
Many practitioners avoid PD in patients with ADPKD over a concern about increased intra-abdominal pressure. A systematic review and meta-analysis of 12 studies in 17,040 patients found no significant differences in adequacy, technique failure, or PD-related complications between those with ADPKD and those without (6). Although the risk of hernia or leak is higher in patients with ADPKD, studies have not shown a resulting increased risk of transfer to HD (7, 8). Notably, in patients undergoing hernia repair, PD does not need to be withheld; low-volume supine dialysis can be performed as the wound heals.
Myth 4: PD is not a good option for elderly patients
Elderly patients have several perceived barriers that preclude PD as a viable dialysis option. Some of them include visual impairment, restricted dexterity, and mild cognitive impairment. However, if PD is the patient’s modality of choice, it is important to recognize that these issues can be overcome with extended training or assisted PD (9). Currently, there is no general recommendation about an ideal dialysis modality for this population. Observational trials have produced mixed outcomes, and randomized controlled trials are not feasible (9). With unclear evidence, patients should be counseled about the full spectrum of dialysis modalities, and shared decision-making should guide the choice. In two closely matched cohorts of PD and HD patients over the age of 65, quality of life was similar if not better in those using PD, suggesting its suitability for this population (10).
Myth 5: PD is not a good option for patients who have experienced kidney graft failure
Individuals requiring dialysis after graft loss are believed by some to be poor candidates for PD. This outlook may be due to prior surgery, immunosuppression, and less predictable residual kidney function. Four analyses of this population have been made, and all have shown no difference in mortality between HD and PD (11–13). More contemporary cohorts have shown better survival than earlier cohorts regardless of modality. Despite these findings, PD was initiated in only 18% of patients with allograft loss in the largest cohort, suggesting significant potential improvement.
Myth 6: PD is not a good option because infections (peritonitis) are more likely to develop
Frequently, concerns over peritonitis lead to avoidance of PD. Interestingly, patients receiving HD are at an increased risk for bloodstream infection. Furthermore, the mortality of bacteremia and sepsis in the end stage kidney disease (ESKD) population far outweighs that in patients with peritonitis (14, 15).
Myth 7: Certain patients and comorbid conditions are associated with PD failure and discontinuation
Switching from PD to HD can be disruptive and is associated with a decreased quality of life and higher cost. However, the avoidance of PD because of concerns about failure or discontinuation, based on a particular demographic or comorbid condition, is unfounded. Shen et al. (16) evaluated the factors leading to technique failure and modality discontinuation in 1587 patients from 1996 to 1997 using the United States Renal Data System database. In their study, technique failure was defined as switching from PD to HD for ≥30 days. That study found no association of diabetes, obesity, or education level with technique failure. Furthermore, the following risk factors were identified: male gender, Black race, systolic blood pressure of 140 to 160 mm Hg, retirement, or disablement. The authors concluded that sociodemographic factors outweighed clinical factors, noting that increased social and financial support would help avoid technique failure. Paradoxically, a more recent review found that time to technique failure showed no differences related to gender, race, or body mass index. From 2009 to 2014, Workeneh et al. (17) followed up 128 incident PD patients and found that the principal reasons for PD withdrawal included peritonitis (30%); catheter dysfunction (18%); ultrafiltration failure (16%); patient choice or lack of support (16%); and hernia, leak, or other surgical complications (6%).
In conclusion, there are many myths concerning candidacy for PD. As nephrologists, we must be comprehensive and impartial when discussing dialysis modalities. Furthermore, in the absence of contraindications, we must focus on inclusivity and work to better accommodate our patients who choose PD as their preferred modality.
References
- 1.↑
Saran R, et al. US Renal Data System 2019 Annual Data Report: Epidemiology of Kidney Disease in the United States. Am J Kidney Dis 2020; 75 (1 Suppl 1):A6–A7. doi: 10.1053/j.ajkd.2019.09.003
- 2.↑
Lee MB, Bargman JM. Myths in peritoneal dialysis. Curr Opin Nephrol Hypertens 2016; 25:602–608. doi: 10.1097/MNH.0000000000000274
- 3.↑
Couchoud C, et al. Dialysis modality choice in diabetic patients with end-stage kidney disease: A systematic review of the available evidence. Nephrol Dial Transplant 2015; 30:310–320. doi: 10.1093/ndt/gfu293
- 4.↑
Twardowski ZJ, et al. Four-year experience with swan neck presternal peritoneal dialysis catheter. Am J Kidney Dis 1996; 27:99–105. doi: 10.1016/s0272-6386(96)90036-0
- 5.↑
Snyder JJ, et al. Body size and outcomes on peritoneal dialysis in the United States. Kidney Int 2003; 64:1838–1844. doi: 10.1046/j.1523-1755.2003.00287.x
- 6.↑
Zhang T, et al. Is peritoneal dialysis a suitable renal replacement therapy option for polycystic kidney disease patients? Kidney Blood Press Res 2018; 43:1539–1553. doi: 10.1159/000494020
- 7.↑
Dupont V, et al. Outcome of polycystic kidney disease patients on peritoneal dialysis: Systematic review of literature and meta-analysis. PLoS One 2018; 13:e0196769. doi: 10.1371/journal.pone.0196769
- 8.↑
Jankowska M, et al. Peritoneal dialysis as a treatment option in autosomal dominant polycystic kidney disease. Int Urol Nephrol 2015; 47:1739–1744. doi: 10.1007/s11255-015-1087-9
- 9.↑
Segall L, et al. Dialysis modality choice in elderly patients with end-stage renal disease: A narrative review of the available evidence. Nephrol Dial Transplant 2017; 32:41–49. doi: 10.1093/ndt/gfv411
- 10.↑
Brown EA, et al. Broadening options for long-term dialysis in the elderly (BOLDE): Differences in quality of life on peritoneal dialysis compared to haemodialysis for older patients. Nephrol Dial Transplant 2010; 25:3755–3763. doi: 10.1093/ndt/gfq212
- 11.↑
Perl J, et al. Impact of dialysis modality on survival after kidney transplant failure. Clin J Am Soc Nephrol 2011; 6:582–590. doi: 10.2215/CJN.06640810
- 12.
Davies SJ. Peritoneal dialysis in the patient with a failing renal allograft. Perit Dial Int 2001; 21 (Suppl 3):S280–S284. PMID: 11887836
- 13.↑
de Jonge H, et al. Comparison of peritoneal dialysis and haemodialysis after renal transplant failure. Nephrol Dial Transplant 2006; 21:1669–1674. doi: 10.1093/ndt/gfl010
- 14.↑
Pérez Fontan M, et al. Peritonitis-related mortality in patients undergoing chronic peritoneal dialysis. Perit Dial Int 2005; 25:274–284. PMID: 15981776
- 15.↑
Abou Dagher G, et al. Sepsis in hemodialysis patients. BMC Emerg Med 2015; 15:30. doi: 10.1186/s12873-015-0057-y
- 16.↑
Shen JI, et al. Determinants of peritoneal dialysis technique failure in incident US patients. Perit Dial Int 2013; 33:155–166. doi: 10.3747/pdi.2011.00233
- 17.↑
Workeneh B, et al. Causes for withdrawal in an urban peritoneal dialysis program. Int J Nephrol 2015; 2015:652953. doi: 10.1155/2015/652953