This interactive case study was organised and funded by Vantive Global Medical Affairs. Technical and medical writer support was provided by EMJ.
Why Are You Still Avoiding Peritoneal Dialysis for Patients with Obesity?
Start
1/19
Nephrology
2/19
These interactive case studies were developed with support from Peter Rutherford, Global Medical Affairs VP, Vantive LLC; and Robin Cooper, Global Medical Affairs Manager, Vantive LLC.
Disclosure
This is a hypothetical patient case and outcomes may not be reflective of clinical studies or real-life circumstances. This includes reference to agents that may be used off-label or for unlicensed indications. The mention of these agents and their uses is intended solely for educational purposes and should not be considered an endorsement or recommendation for their use outside approved indications. Please always consult guidelines and local prescribing information in your country of practice, as information may vary.
Disclaimer
3/19
Case Presentation
You have been following your patient for 2 years in the outpatient clinic and he is approaching the need for dialysis. According to his Kidney Failure Risk Equation, he will need to start dialysis within the next few months, and it is now time to begin discussions with the patient and his family about their renal replacement options.
In this interactive case study, you will: 1. Identify the patient’s renal replacement options 2. Evaluate factors that may impact risk to the patient with each option
Type 2 diabetes Hyperlipidaemia Hypertension Chronic kidney failure Hyperkalaemia Peripheral oedema Albuminuria Mild persistent asthma
Diagnoses:
4/19
Age: 42 years Sex: Male Height: 72 inches (183 cm) Weight: 280 lbs (127 kg) BMI: 38 kg/m2 BSA: 2.46 kg/m2 (Du Bois)
Medical History:
Peripheral oedema
Normal
Oedema
Type 2 diabetes
Hyperlipidaemia
Hypertension
Chronic kidney failure due to hypertension
Hyperkalaemia
Albuminuria
High albumin in urine
Mild persistent asthma
Glucose transporter
• GFR: 15 mL/min/1.73m2 • Urea (BUN): 1.43 mmol/L (4 mg/dL) • Glucose: 6.1 mmol/L (110 mg/dL) • CO₂: 20 mmol/L (20 mEq/L) • Ca: 1.85 mmol/L (7.4 mg/dL) • Na: 145 mmol/L (145 mEq/L) • K: 6.4 mmol/L (6.4 mEq/L) • Chloride: 101 mmol/L (101 mEq/L) • Hgb: 6.1 mmol/L (9.9 g/dL) • Albumin: 37 g/L (3.7 g/dL) • Phosphorous: 1.45 mmol/L (4.5 mg/dL) • Bicarbonate: 20 mmol/L (20 mEq/L)
Laboratory Results
5/19
Blood tests:
• PCR: 90.5 mg/mmol (800 mg/g) • Protein present • uACR: 80 mg/mmol (707 mg/g)
Urine tests:
BUN: blood urea nitrogen; CO2: carbon dioxide; Ca: calcium; Na: sodium; K: potassium; Hgb: haemoglobin; PCR: protein-to-creatinine ratio; GFR: glomerular filtration rate; uACR: urine-albumin-creatinine ratio.
Is the patient at risk of kidney failure? Use the Kidney Failure Risk Equation to find out.
GFR:
Age:
Sex:
uACR:
Reveal
Click to reveal patient data:
Urine
Sex
Age
GLOMERULAR FILTRATION RATE
THE PROJECTED RISK OF KIDNEY FAILURE
=
+
Calculating Kidney Failure Risk
Ca: calcium; GFR: glomerular filtration rate; uACR: urine-albumin-creatinine ratio.
Laboratory tests reminder
GFR: 15 mL/min/1.73m2 Urea (BUN): 1.43 mmol/L (4 mg/dL) Glucose: 6.1 mmol/L (110 mg/dL) CO₂: 20 mmol/L (20 mEq/L) Ca: 1.85 mmol/L (7.4 mg/dL) Na: 145 mmol/L (145 mEq/L) K: 6.4 mmol/L (6.4 mEq/L) Chloride: 101 mmol/L (101 mEq/L) Hgb: 6.1 mmol/L (9.9 g/dL) Albumin: 37 g/L (3.7 g/dL) Phosphorous: 1.45 mmol/L (4.5 mg/dL) Bicarbonate: 20 mmol/L (20 mEq/L)
PCR: 90.5 mg/mmol (800 mg/g) Protein present uACR: 80 mg/mmol (707 mg/g)
1. Kidney Failure Risk Calculator. Available at: https://www.kidneyfailurerisk.com/. Last accessed: 27 March 2025.
Using the patient’s urine, sex, age, and GFR, the Kidney Failure Risk Equation1 provides the 2- and 5-year probability of treated kidney failure for a potential patient with CKD Stage 3–5.
For further information on calculating kidney function risk, use the Kidney Failure Risk Equation, see resources at the end of case study.
15
42
M
80
Ca:
Bicarbonate:
Phosphorous:
Albumin:
For improved accuracy, additional parameters are included:
1.85
20
1.45
37
At 2 Years 80.18% At 2 Years 99.48%
The Kidney Risk Equation identifies the patient as requiring dialysis:
STAGE 4: Severe decrease in function Potential risk of progression to kidney failure requiring dialysis or transplant:
This patient requires thorough dialysis education and planning for access formation.
Based on clinical history and comorbidities, which renal replacement therapies are suitable for the patient?
6/19
1. Kennedy C, Bargman J. Peritoneal dialysis in the obese patient. Clin J Am Soc Nephrol. 2020;15(2):276-8. 2. Brown EA et al. International Society for Peritoneal Dialysis practice recommendations: prescribing high-quality goal-directed peritoneal dialysis. Perit Dial Int. 2020;40(3):244-53.
A
Standard automated (PD)
Answer is E
Patients with obesity should be carefully considered for PD and issues unique to obesity openly discussed. While obesity may pose technical challenges in PD, it is not a contraindication, and dialysis modality should be individualised according to patient preference and clinical suitability.1,2
B
Continuous ambulatory PD
C
At home haemodialysis (HD)
D
In-centre HD
E
All of the above
F
Only C and D
G
None of the above
What outcomes associated with PD do you expect for patients with obesity?
7/19
1. Kennedy C, Bargman J. Peritoneal dialysis in the obese patient. Clin J Am Soc Nephrol. 2020;15(2):276-8. 2. Quero M et al. Impact of obesity on the evolution of outcomes in peritoneal dialysis patients. Clin Kidney J. 2020;14(3):969-82. 3. Lambie M, Davies S. An update on absolute and relative indications for dialysis treatment modalities. Clin Kidney J. 2023;16(Suppl 1):i39-i47.
Inadequate therapy
Answer is G
PD can generally be performed effectively in most patients with obesity who are otherwise appropriate candidates. However, the concerns noted above require careful consideration, along with additional issues specific to patients with obesity on PD.1-3 Click through to continue learning.
Exit site infections cannot be managed with patients who are obese
Transfer to in-centre HD within a year
Increased mortality as compared to patients with obesity on other modalities
A, C, and D
Data Debunk: Obesity as a Relative Contraindication for PD
8/19
Low glucose PD therapy can minimise weight gain.1 • Data indicate that fat weight gain is greater on HD.2 • A multidisciplinary team including clinical dietitians and counsellors can support patients with obesity starting dialysis, with pilot data suggesting this approach may facilitate significant and sustained weight loss in select cases.3
References
Wolfson M et al.; Icodextrin Study Group. A randomized controlled trial to evaluate the efficacy and safety of icodextrin in peritoneal dialysis. Am J Kidney Dis. 2002;40(5):1055-65. Lievense H et al. Relationship of body size and initial dialysis modality on subsequent transplantation, mortality and weight gain of ESRD patients. Nephrol Dial Transplant. 2012;27(9):3631-8. Hollis J et al. Longitudinal evaluation of a weight reduction program for patients on peritoneal dialysis. Perit Dial Int. 2005;25 Suppl 3:S152-4. Quero M et al. Impact of obesity on the evolution of outcomes in peritoneal dialysis patients. Clin Kidney J. 2020;14(3):969-82. McDonald SP et al. Obesity is a risk factor for peritonitis in the Australian and New Zealand peritoneal dialysis patient populations. Perit Dial Int. 2004;24(4):340-6. Lambie M, Davies S. An update on absolute and relative indications for dialysis treatment modalities. Clin Kidney J. 2023;16(Suppl 1):i39-i47. Perl J et al. Peritoneal dialysis-related infection rates and outcomes: results from the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS). Am J Kidney Dis. 2020;76(1):42-53. Crabtree JH et al. Creating and maintaining optimal peritoneal dialysis access in the adult patient: 2019 update. Perit Dial Int. 2019;39(5):414-36. Ng JKC et al. Obesity, weight gain, and fluid overload in peritoneal dialysis. Front Nephrol. 2022 Jun 28;2:880097.
High BMI does not translate into a survival disadvantage. A longitudinal, retrospective registry study by Quero et al.4 reported the following: There were no BMI-related differences in patients who developed peritonitis in the first 3 years of PD. When adjusted for age, there was no BMI difference for patients under 65 years old who transferred to HD. There was no difference in the probability of death in different BMI groups.
Increased BMI has been associated with a modest increased risk of transfer to HD and risk of exit site infection,5 although this was not observed in the PDOPPS observational prospective cohort study.6,7 PD in patients with severe obesity (BMI >40) is an access challenge.8,9
Click through to learn more.
What are the important considerations for PD catheter placement in patients with obesity?
9/19
1. Crabtree JH et al. Creating and maintaining optimal peritoneal dialysis access in the adult patient: 2019 update. Perit Dial Int. 2019;39(5):414-36. 2. Khan SF, Rosner MH. Optimizing peritoneal dialysis catheter placement. Front Nephrol. 2023;3:1056574.
Use of an extended catheter
Answer is D
The ISPD guidelines emphasise that optimal PD catheter placement requires consideration of extended catheter use, careful exit-site positioning, and performance by an experienced surgeon trained in extended catheter techniques.1,2 Continue to explore key outcomes and patient considerations.
Placement of the exit site
A surgeon who is trained and experienced on placement of extended catheters
All the above
Challenges Associated with Obesity and Access Creation for HD and PD
10/19
1. Raulli SJ et al. Higher body mass index is associated with reinterventions and lower maturation rates after upper extremity arteriovenous access creation. J Vasc Surg. 2021;73(3):1007-15. 2. Crabtree JH et al. Creating and maintaining optimal peritoneal dialysis access in the adult patient: 2019 update. Perit Dial Int. 2019;39(5):414-36.
HD may pose additional access-related challenges in patients with high BMI.1
Continue to learn more about optimising PD catheter access for this patient
HD Fistula Issues1
PD Catheter Placement Issues2
Higher rate of re-interventions
Lower rate of maturation
Use of extended PD catheters
Optimisation of exit site to prevent infection
Extended Catheter Systems for Patients with Obesity
The success of PD as renal replacement therapy requires a safe, functional, durable catheter access to the peritoneal cavity.1
11/19
1. Crabtree JH et al. Creating and maintaining optimal peritoneal dialysis access in the adult patient: 2019 update. Perit Dial Int. 2019;39(5):414-36. 2. Kennedy C, Bargman J. Peritoneal dialysis in the obese patient. Clin J Am Soc Nephrol. 2020;15(2):276-8.
Upper border of Pubic Symphysis
Insertion incision
Extended catheter with an upper abdominal exit site. Adapted with permission from Crabtree et al, 2019.1
The exit site of the catheter should be placed so that it is visible to the patient and can be kept dry to minimise risk of exit site infection.2
The following should be considered when assessing patients with a high BMI for PD
12/19
1. Ng JKC et al. Obesity, weight gain, and fluid overload in peritoneal dialysis. Front Nephrol. 2022;2:880097. 2. Su WS et al. waist-to-hip ratio, cardiovascular outcomes, and death in peritoneal dialysis patients. Int J Nephrol. 2010;2010:831243.
Muscle mass
Considering muscle mass, fluid retention, and waist-to-hip ratio is crucial when assessing high BMI patients for PD. These factors provide a more accurate evaluation of body composition and health risks, leading to better-informed treatment decisions.1,2
Fluid retention
Waist-hip ratio
Fat Versus Muscle in Patients with a High BMI
Body weight has been described as an unreliable measurement of obesity, as it does not distinguish body composition.1 The body composition of a patient with high BMI is an important consideration in PD use.1,2
13/19
1. Ng JKC et al. Obesity, weight gain, and fluid overload in peritoneal dialysis. Front Nephrol. 2022;2:880097. 2. Mehrotra, R. Obesity in peritoneal dialysis. Available at: https://ispd.org/wp-content/uploads/3.-Raj-Mehrotra-Obesity-in-PD.pdf. Last accessed: 11 September 2025.
• There is greater daily production of nitrogenous waste. • Clearances can become suboptimal in low transporters (10–15% of PD patients) only when they become anuric. • Even in these patients, as long as they make urine, adequate clearances can be achieved.
If a patient is large because of a large muscle mass:2
FYI: Consider higher fill volumes in patients1 with obesity
Fat Mass
Fat free muscle/ Lean mass
If a patient is large because of large fat mass:2
Fat mass does not contribute to production of nitrogenous uremic toxins. The problem in people with obesity is mathematics (the calculation of V) and not a clinical problem relevant for patients.
Consider higher fill volumes in patients with obesity As patient body weight increases, PD clearance per kg declines because peritoneal membrane surface area grows more slowly than body water.1 Therefore, heavier patients often require higher fill volumes or more exchanges to achieve adequate Kt/V.1
Peritoneal Dialysis Adequacy: Getting the Numbers Right
Kt/V is a common measure of dialysis adequacy. It quantifies how effectively dialysis is removing urea from the blood:
14/19
1. Kennedy C, Bargman J. Peritoneal dialysis in the obese patient. Clin J Am Soc Nephrol. 2020;15(2):276-8. 2. K/DOQI; National Kidney Foundation. Clinical practice guidelines for nutrition in chronic renal failure. Am J Kidney Dis. 2000;35(6 Suppl 2):S17-S104.
K (Dialyser clearance)× t (Time) V (volume of distribution of urea)
Kt/V =
The use of Kt/V to assess adequacy of dialysis for patients with obesity has limitations because adipose tissue has low water content and does not increase the volume of distribution of urea.1 The Kidney Disease Outcomes Quality Initiative (KDOQI) recommends that the lean body weight be used to calculate V.2
Patients with obesity have a higher fat percentage than lean patients.1 Adipose tissue holds less water than lean tissue; therefore, when actual body weight is used, volume (V) is over estimated.1
If actual body weight is used to calculate Kt/V, the estimation of V will be falsely high, and the Kt/V will be falsely low.1 Clinically, the patient may actually be receiving adequate urea clearance, but Kt/V suggests under-dialysis. Guidelines suggest using multiple measures of adequacy, including focusing on clinical and other biochemical measures of adequacy.1
Lean
Obese
Volume (L)
Estimated Versus True Volume
True V
Estimated V
15/19
Peritoneal Dialysis Adequacy: A Goal Directed Approach
ISPD recommends a goal-directed approach that focuses on:1
• Individualised, person-centred decision making. • Supporting the patient’s quality of life by helping them achieve their personal and life goals. • Reducing symptoms and minimising treatment burden. • Ensuring delivery of safe, high-quality dialysis care that considers residual kidney function, volume status, and solute removal. • Preserving renal function and improving nutritional status.
1. Brown EA et al. International Society for Peritoneal Dialysis practice recommendations: prescribing high-quality goal-directed peritoneal dialysis. Perit Dial Int. 2020;40(3):244-53.
Now that you have seen the scientific data, you have discussed PD as well as HD and your patient prefers PD. What is your level of confidence in prescribing PD?
16/19
No confidence
There is no incorrect answer
Using shared decision-making, the overarching goal is to establish a realistic care strategy with your patient that not only allows them to maintain quality of life, but enables them to meet their life goals while minimising symptoms and treatment burden.1 To continue your learning, please find additional resources at the end of this case study.
Absolutely no problems - confident
I still have some concerns
1. Kennedy C, Bargman J. Peritoneal dialysis in the obese patient. Clin J Am Soc Nephrol. 2020;15(2):276-8. 2. Brown EA et al. International Society for Peritoneal Dialysis practice recommendations: prescribing high-quality goal-directed peritoneal dialysis. Perit Dial Int. 2020;40(3):244-53. 3. Crabtree JH et al. Creating and maintaining optimal peritoneal dialysis access in the adult patient: 2019 update. Perit Dial Int. 2019;39(5):414-36 . 4. Quero M et al. Impact of obesity on the evolution of outcomes in peritoneal dialysis patients. Clin Kidney J. 2020;14(3):969-82.
Extended catheter systems should be utilised and the exit site of the catheter should be placed so that it is visible to the patient and can be kept dry to minimise risk of exit site infection.1
Take Homes
17/19
Obesity should not be viewed as a barrier to accessing the full range of renal replacement therapy options.1,2 The success of PD requires a safe, functional, durable catheter access to the peritoneal cavity. 3
The use of Kt/V to assess adequacy for patients with obesity has limitations and lean body weight should be considered in patients with higher adiposity.1
Prescribe low glucose PD solutions to minimise weight gain. Importantly, no BMI-related differences in:4
• Risk of peritonitis within first 3 years of PD. • Transfer to HD (after adjusting for age <65 years). • Probability of death across BMI groups.
18/19
Learning Resources
Kidney Failure Risk Equation: https://kidneyfailurerisk.com/
Using Ideal Body Weight to Measure PD Adequacy: https://pmc.ncbi.nlm.nih.gov/articles/PMC8995486/
PD Catheter Choice: https://journals.sagepub.com/doi/pdf/10.3747/pdi.2018.00232
19/19
Thank you
