Perspectives on Peritoneal Dialysis

Overview

• Prevalence of PD as an RRT Modality– Internationally and Locally

• Factors influencing PD utilisation– Survival Data / Residual Renal Function– Acute Unplanned PD– PD in Acute Kidney Injury– “PD First”

• PD as a bridge to Transplantation• Assisted PD

International Variation in Modality

Rates of PD in developing world increasing 8-10%/annum

Developing countries noted prevalence increase by 300% past 10 years.

International Variation in PD

Prevalent Patients in UK by RRT Modality (1997-2010)

Where does PD fit into a Renal Replacement Programme?

Low Clearance

Peritoneal Dialysis

Haemo-dialysis

Transplantation

Conservative Therapy

RRT start at 90 days by modality (2009-2010) (Renal Registry 2011)

Area HD (%) PD (%) Transplant (%)

England (N =5605) 67 18.6 8.7

Leicester (N = 217) 67.5 18.7 13.8

Chelmsford (N=47) 53.3 42.2 4.4

N. Ireland (N=172) 90.7 6.0 3.3

RRT start at 90 days by modality (2011-2012) (Renal Registry 2013)

Area HD (%) PD (%) Transplant (%)

England (N =5797) 70.1 18.6 9.1

N. Ireland (N=205) 73.5 14.5 12.4

How do you keep competing RRT modalities viable in a renal unit?

Is there potential competition with other Home Dialysis Modalities?

(Almost) Mutually Exclusive Demographics• Age / Sex / Cause of ESRD• Co-morbid Profile• ESRD Vintage

Why such variation in PD Therapy provision?

Factors influencing PD utilization

1. Financial factors• Reimbursement rates

2. Centre factors• Dialysis staff opinion or bias• PD experience• HD availability

3. Patient factors• Opinion of primary care physician• Geography• Timing of nephrology referral

4. Socio-economic factors• Structure of dialysis program• Number of dialysis centres

5. Cultural factors• Attitude towards chronic disease• Attitude towards home therapy

Peritoneal Dialysis vs. Haemodialysis

Mortality Rates between Modality

Mortality figures between modality originally noted conflicting ‘survival advantage’ results in PD patients compared with HD.– Most found survival advantage lost after first 2

years of therapy– Raised suggestions about elective switch

from PD to HD

CVC impacts association between modality and survival◻ 1-year mortality ⬜HD-AVF/AVG and PD similar⬜HD-CVC 80% higher than PD

◻ Use of CVCs in incident HD patients largely accounts for the early survival benefit seen with PD

Mortality Rates between Modality

Mortality rates between ‘planned’ and ‘unplanned’ dialysis often discrepant.

‘Peritoneal dialysis and haemodialysis associate with similar survival among incident dialysis patients who initiate dialysis electively, as outpatients, after at least 4 months of predialysis care…’

Quinn et al. JASN (2011)

What about Residual Renal Function?

Role of Residual Renal FunctionResidual renal function in either modality is

associated with a lower risk of death.Peritoneal Dialysis

NECOSAD-2 Study (based on renal kt/V)JASN (2004); 15: 1061–1070

HaemodialysisShemin et al. (Based on Measured Creatinine Clearance)

AJKD (2001) 38: 85-90.

Several surrogate markers also associated with RRF e.g. Phosphate Control / Anaemia

CONTRAST Study CJASN (2011)

Peritoneal Dialysis in Acute Kidney Injury

Do we have enough evidence to use it?

PD in AKI - In terminal decline?

• Acute PD associated with higher mortality in patients with AKI secondary to falciparum malaria.

Phu et al. NEJM 2002

However many small trials in paediatric AKI have reported favourable results

High Volume Peritoneal Dialysis in Intensive Care

Sao Paulo Experience (CJASN 2012)• Continuous 2 litre 60-80 minute exchanges

can achieve solute clearances comparable to intermittent daily HD or CVVH

• Recovery of renal function and mortality comparable to alternative dialysis modalities– But ICU Mortality with AKI remains high…– May not be so effective in hypercatabolic patients– Requires intact peritoneum + functional catheter

(~10% of cases had early mechanical complications)

Delivering PD for AKI in Developing Countries

Helping deliver PD in Sub-saharan AfricaPapers published on work in Tanzania / Nigeria / Ghana showing respectable outcomes in small cohorts (Kilonzo et al PDI 2012)

Is acute ‘unplanned’ PD feasible and safe?

Potential Scenarios

◻ Low clearance patient wanting to start HD with an AVF⬜GFR now 7ml/min, AVF hasn’t matured or run out

of options for useful AVF creation

◻ Young patient presents @ ESRD, GFR 6ml/min, Hb 78 g/L, K/HCO3 normal, volume status OK, anorexia, fatigue

What does Urgent PD require?

● Buy in from medical and surgical teams● Access to rapid education/orientation● Access to rapid PD insertion● Access to IPD post insertion

How Quick can you use a PD Catheter?

Overcoming the need for a ‘break-in’ period

• No difference in rates of complications from instant use vs. waiting 3-5 days

Experiences of Acute PD

123 patients starting Acute Unplanned Dialysis (2005-2010) (66 = PD , 57 = HD)44 patients died (36%) within 6 months

Mortality rates (all cause and cardiovascular) not significant difference between modality

HD Patients had higher risk of bacteraemia

Koch et al. NDT (2012) 27 (1):375-380.

PD when all other access options are exhausted

Aitken et al. JVA 201462 patients with bilateral upper extremity stenoses• 8 patients switched to PD - 12 month

patency of 50%

However 11 received DCD transplants - 12 month patency 72%

Peritoneal Dialysis as a Bridge to Transplantation

Any influence on time to transplantation?

Dialysis modality doesn’t appear to influence time to transplant

Chalem et al. found a shorter waiting time for PD patients in Cox proportional models (RR 0.71, P < 0.0001)– statistical significance lost when taking into

account the transplant centre as a variable Kidney International (2005)

Any influence on Transplant outcomes? (1)

Short Term (within 6months)– Patient and Graft survival about the same

regardless of modality

– PD Patients reported to have reduced rate of delayed graft function but increased risk of early graft failure

– Increased risk of graft thrombosis?• Varying size and methodology of studies reporting

association (such as Murphy et al. NDT 1994)

Any influence on Transplant outcomes? (2)

USRDS Analysis

14,508 patients between July 2001 - June 2006 (86% Haemodialysis, 14% Peritoneal Dialysis)

Long Term Graft Function– No apparent difference in acute rejection episodes,

long-term graft survivals, or renal function.

Molnar et al CJASN 2012

All cause mortality according to pre-transplant dialysis modality (Molnar et al. CJASN 2012)

What about assisted PD?

Weighing it all up…PROS

Enables a bridge to ‘self-care’ PD or ongoing PD in event of patient/carer fatigue

Reduced risks of PD peritonitis reported and comparable technique survival (Ayede et al BMC Nephol 2014)

CONSMay be associated with increased mortality and

difficulty in establishing ceiling of treatment in frailer patients

‘Hidden’ costs – trainers / carers / patients

How should assisted PD influence dialysis service provision in the community?

Independent Patients suitable

for Home Therapy

Dependent Patients not suitable for Home

Therapy

aPD

PD

aPDPD

PD

“Pre aPD” Status

“Aspirational” Model

Reality?

Summary

• PD service provision influenced by multiple non-medical factors (and physician preference!)

• PD and HD are intrinsically not equivalent cohorts and hard to compare.

• Some challenges remain as to the appropriate role of PD in dialysis programmes