METABOLISM AND NUTRITION WITH PD OBESITY Rajnish Mehrotra Harborview Medical Center University of Washington, Seattle 1
Body Size in Patients New to Dialysis United States Body Mass Index, kg/m2 33 31 29 27 [VALUE].0 Almost 50% of patients that start dialysis in US are obese 29,4 29,6 25 2007-'09 2010-'12 2013-2015 USRDS Annual Data Report 2017
3 Body Size in Spain Obese, 26% Patients with higher body mass index get more kidney disease So, the body mass index of patients needing dialysis is more than of the general population Overweig ht, 39% Perhaps up to 30% of patients that start dialysis in Spain are obese EPRICE Study: 2746 adults from 42 municipalities in Spain enrolled between 2004 and 2008; representative of the population of Spain Otero et al, Nefrologia 2010; 30: 78-86
30-50% of patients that need dialysis in Europe and United States are obese Do I use a BMI cut-off above which I tell the patient that they cannot do PD? NO
Clinically Relevant Issues for Successful PD in Obese Catheter Placement Peritonitis Solute Clearances, including residual kidney function Weight Gain Access to Transplantation Transfer to in-center hemodialysis Mortality
Challenge Catheter Placement Peritonitis Risk Transplantation Transfer to HD Solution Exit site to be placed such that it is visible to patient and allows for it to be dry This risk is likely modifiable but requires close attention by facility and patient Body size is a problem without regard to dialysis modality Be careful about peritonitis and residual kidney function
SOLUTE CLEARANCES
Large Patients: Fat vs. Muscle In how one is large determines the efficacy of PD If a patient is large because of a large muscle mass: There is greater daily production of nitrogenous waste Clearances are a problem only in low transporters (10-15% of PD patients) only when they become anuric; even in them, as long as they make urine, you can achieve adequate clearances If a patient is large because of large fat mass: Fat mass does not contribute to production of nitrogenous uremic toxins The problem in fat people is mathematics the calculation of V and not a clinical problem relevant for patients
In Obese, Watson Eq Overestimates V We end up dividing Kt by a larger number than we should and get a lower Kt/V than is actually the case Some people say we should use ideal body weight. That is only an opinion, with no study that says it is the right thing to do Johansson et al, J Am Soc Nephrol 2001; 12: 568-73
10 The Real Problem Faster Loss of Residual Kidney Function Has been shown by other studies also Obese patients need closer monitoring of RKF Will need more frequent adjustment of PD prescription to ensure adequate solute clearances Increase PD dose if Kt/V or bicarbonate low; or phosphorus high Obi et al, Am J Kidney Dis 2017 (epub)
Challenge Catheter Placement Peritonitis Risk Solute Clearances Transplantation Transfer to HD Solution Exit site to be placed such that it is visible to patient and allows for it to be dry This risk is likely modifiable but requires close attention by facility and patient Lose residual kidney function faster; need closer monitoring and adjustment of prescription Body size is a problem without regard to dialysis modality Be careful about peritonitis and residual kidney function
WEIGHT GAIN In Defense of the Small Guy Glucose
Glucose Absorption or Improvement in Appetite Loss of appetite is a common symptom of kidney failure When we start dialysis (HD or PD), patients eat more When people eat more, they gain weight Mehrotra et al, Am J Kidney Dis 2002; 40: 133-142
Effect of Dialysis Modality on Weight Change Over Time NECOSAD Study: HD, 132; PD, 118 Open squares, HD Closed squares, PD After adjustment for baseline body weight Jager et al, J Am Soc Nephrol 2001; 12: 1272-9
Effect of Dialysis Modality on Weight Change Over Time Weight Gain PD HD Odds Ratio (Ref: HD) N % N % Minimally Adjusted Fully Adjuted Propensity-Score Matched Cohort (687 pairs) > 2% 170 25 211 31 0.74 (0.58-0.94) 0.69 (0.52-0.91) > 5% 115 17 150 22 0.71 (0.54-0.94) 0.63 (0.46-0.88) > 10% 51 7 82 12 0.61 (0.42-0.88) 0.58 (0.37-0.89) Unmatched incident cohort (PD, 687; HD, 36,994) > 2% 170 25 10,957 30 0.78 (0.66-0.93) 0.82 (0.69-0.99) > 5% 115 17 7,322 20 0.82 (0.67-1.00) 0.88 (0.72-1.09) > 10% 51 7 3,575 10 0.75 (0.57-1.00) 0.82 (0.61-1.10) Livense et al Nephrol Dial Transplant 2012; 27: 3631-8
PD: Greater Weight Gain? Badve et al, Plos One 2014; 9: e114897
Challenge Catheter Placement Peritonitis Risk Solute Clearances Solution Exit site to be placed such that it is visible to patient and allows for it to be dry This risk is likely modifiable but requires close attention by facility and patient Lose residual kidney function faster; need closer monitoring and adjustment of prescription Weight Gain Patients gain weight when they start dialysis whether HD or PD. Obese patients can do PD or HD Transplantation Transfer to HD Body size is a problem without regard to dialysis modality Be careful about peritonitis and residual kidney function
MORTALITY
Obese PD Patients Higher Mortality Australia-New Zealand McDonald et al, J Am Soc Nephrol 2003; 2894-901
Obese PD Patients Lower Mortality United States Body Mass Index, kg/m 2 Hazards Ratio < 21.88 Reference 21.88-24.61 0.90 (0.86-0.94) 24.61-27.43 0.82 (0.79-0.86) 27.43-31.37 0.86 (0.82-0.90) > 31.37 0.94 (0.89-0.98) Mehrotra et al, Kidney Int 2009; 76: 97-109
Summary Evidence 0.79 (0.57-1.09) 1.20 (0.95-1.51) 1-year 2-year 1.07 (0.93-1.23) 3-5-year Ahmadi et al, Perit Dial Int 2016; 36: 315-25
What About Compared to HD? Table 3. HR of death in PD patients (reference: incident HD patients), stratified by BMI PD HD HR (95% CI) (ref. HD) n % Death n % Death Minimally adjusted Case-mix adjusted Case-mix and laboratory adjusted Propensity score-matched cohort <18.50 118 42 118 42 0.83 (0.55 1.27) 0.71 (0.45 1.15) 0.56 (0.30 1.04) 18.50 24.99 1419 37 1419 46 0.81 (0.72 0.91) 0.87 (0.77 0.98) 0.80 (0.69 0.92) 25.00 29.99 1304 34 1304 44 0.78 (0.69 0.89) 0.85 (0.74 0.97) 0.81 (0.70 0.94) 30.00 1167 35 1167 42 0.93 (0.81 1.06) 1.05 (0.91 1.21) 1.08 (0.92 1.25) Total 4008 36 4008 39 0.83 (0.78 0.89) 0.91 (0.85 0.98) 0.88 (0.81 0.95) Unmatched incident cohort <18.50 118 42 2460 59 0.60 (0.45 0.79) 0.84 (0.63 1.12) 0.79 (0.59 1.06) 18.50 24.99 1419 37 21 358 50 0.67 (0.61 0.73) 0.85 (0.77 0.92) 0.77 (0.71 0.85) 25.00 29.99 1304 34 16 849 44 0.74 (0.67 0.81) 0.90 (0.81 0.99) 0.87 (0.79 0.97) 30.00 1167 35 17 804 38 0.91 (0.82 1.00) 1.10 (1.00 1.22) 1.02 (0.92 1.13) Total 4008 36 58 471 45 0.75 (0.71 0.79) 0.92 (0.87 0.97) 0.86 (0.81 0.91) a In patients that are not obese, patients treated with PD have a lower death risk In obese patients, risk for death is the same with PD and with HD Livense et al Nephrol Dial Transplant 2012; 27: 3631-8
Challenge Catheter Placement Peritonitis Risk Solute Clearances Weight Gain Transplantation Transfer to HD Mortality Solution Exit site to be placed such that it is visible to patient and allows for it to be dry This risk is likely modifiable but requires close attention by facility and patient Lose residual kidney function faster; need closer monitoring and adjustment of prescription Patients gain weight when they start dialysis whether HD or PD. Obese patients can do PD or HD Body size is a problem without regard to dialysis modality Be careful about peritonitis and residual kidney function In HD, obese patients have lower mortality; in PD, no difference in mortality in obese and non-obese. In those that are obese, no difference in survival when treated with PD or HD
Summary and Conclusions PD can be successfully done in the obese but need to focus on: Placement of PD catheter Preventing peritonitis Monitoring residual kidney function and adjust PD prescription more often Greater weight gain with PD is more a myth than fact: Glucose causes many problems, but contribution to weight gain has been over-estimated Mortality of obese PD patients same as of non-obese PD patients, and of obese HD patients