Blood pressure and mortality risk in peritoneal dialysis patients in England and Wales Udaya P.Udayaraj   , R.Steenkamp, F...
Introduction   <ul><li>General population – linear or ‘J’ shaped association of  BP with mortality </li></ul>Lewington et ...
Introduction   <ul><li>‘ Reverse J’  or  ‘ U’ association well described in hemodialysis (HD) patients </li></ul>Kalantar-...
Introduction  <ul><li>Is this ‘reverse’ association related to HD procedure? </li></ul><ul><ul><li>Creation of AV fistula ...
Introduction <ul><li>Previous studies in peritoneal dialysis (PD) patients – inconsistent results due to small sample size...
Aim <ul><li>To study the association of BP and mortality in </li></ul><ul><li>a larger cohort of peritoneal dialysis patie...
Methods (Databases) <ul><li>UK Renal Registry (UKRR) </li></ul><ul><ul><li>Established in 1997 </li></ul></ul><ul><ul><li>...
Study population <ul><li>Incident RRT patients 1997-2004 in England and Wales </li></ul><ul><ul><li>Inclusion criteria </l...
Statistical analysis <ul><li>BP measurements </li></ul><ul><ul><li>Mean BP value in the 1 st /2 nd  quarter of RRT </li></...
<ul><li>Outcome </li></ul><ul><ul><li>All cause mortality after day 90 </li></ul></ul><ul><ul><li>All patients followed un...
Results   (Study cohort) <ul><li>Cohort selection   no. of patients </li></ul><ul><li>included </li></ul><ul><li>PD at day...
Baseline Characteristics   Renal Association  UK Renal Registry
P< 0.0002 P= 0.01 † Adjusted for age, gender, cause of renal failure, ethnicity, lab parameters, treatment modality, time ...
† Adjusted for age, gender, cause of renal failure, ethnicity, lab parameters, treatment modality, time to transplant wait...
Subgroup analyses – Time to transplant waiting list (WL) †  Survival after 1 year,  Adjusted for age, gender, cause of ren...
Subgroup analyses - Diabetes <ul><li>Diabetic – no association of any BP component with mortality </li></ul><ul><li>Non di...
Summary <ul><li>Pattern of association of BP and mortality was </li></ul><ul><ul><li>For the entire study population  </li...
<ul><li>Strengths </li></ul><ul><ul><li>Largest study to date on PD patients </li></ul></ul><ul><ul><li>First to describe ...
Conclusions <ul><li>High and low SBP are risk factors for increased mortality in incident PD patients </li></ul><ul><li>Lo...
 
Baseline Characteristics
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Blood pressure and mortality risk in peritoneal dialysis patients

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Blood pressure and mortality risk in peritoneal dialysis patients

  1. 1. Blood pressure and mortality risk in peritoneal dialysis patients in England and Wales Udaya P.Udayaraj , R.Steenkamp, F.Caskey, D.Ansell, C.Tomson UK Renal Registry, Bristol, UK www.renalreg.org Renal Association UK Renal Registry
  2. 2. Introduction <ul><li>General population – linear or ‘J’ shaped association of BP with mortality </li></ul>Lewington et al. Lancet, 2002; 360:1903-13 Renal Association UK Renal Registry
  3. 3. Introduction <ul><li>‘ Reverse J’ or ‘ U’ association well described in hemodialysis (HD) patients </li></ul>Kalantar-Zadeh. Hypertension, 2005;45:811-17 Zager et al. KI,1998;54:561-69 Renal Association UK Renal Registry
  4. 4. Introduction <ul><li>Is this ‘reverse’ association related to HD procedure? </li></ul><ul><ul><li>Creation of AV fistula can predispose to myocardial ischemia ‡ </li></ul></ul><ul><ul><li>Hypotension during HD can precipitate myocardial ischemia * and is associated with increased mortality † </li></ul></ul><ul><ul><li>‡ Savage et al. AJKD 2002; 40: 753-59 </li></ul></ul><ul><li>* Selby et al. Semin Dial 2007; 20:220-28 </li></ul><ul><ul><li>† Shoji et al. KI 2004; 66:1212-20 </li></ul></ul>Renal Association UK Renal Registry
  5. 5. Introduction <ul><li>Previous studies in peritoneal dialysis (PD) patients – inconsistent results due to small sample size † or short follow up ‡ </li></ul><ul><li>Low BP associated with lower mortality in kidney transplant recipients </li></ul><ul><li>Association of BP and survival amongst dialysis patients awaiting transplantation is not known </li></ul><ul><ul><ul><ul><ul><li>‡ Rumyantazev et al. NDT 2005;20:1693-1701 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Rocco et al. Perit Dial Int 22: 371-379, 2002 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>† Lynn et al. KI 2002;62:2281-2287 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Ates et al. Kidney Int 60: 767-776, 2001 </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Jager et al. Kidney Int 55: 1476-1485, 1999 </li></ul></ul></ul></ul></ul>Renal Association UK Renal Registry
  6. 6. Aim <ul><li>To study the association of BP and mortality in </li></ul><ul><li>a larger cohort of peritoneal dialysis patients </li></ul><ul><li>a subgroup of patients who are registered on the kidney transplant waiting list </li></ul>Renal Association UK Renal Registry
  7. 7. Methods (Databases) <ul><li>UK Renal Registry (UKRR) </li></ul><ul><ul><li>Established in 1997 </li></ul></ul><ul><ul><li>100 % coverage of England and Wales expected by 2007 </li></ul></ul><ul><ul><li>Fully electronic data extraction from clinical information system </li></ul></ul><ul><ul><li>Quarterly biochemical and clinical data on all patients on renal replacement therapy (RRT) </li></ul></ul><ul><li>UK Transplant (UKT) </li></ul><ul><ul><li>Maintains national organ donor register </li></ul></ul><ul><ul><li>Holds data on kidney transplant waiting list </li></ul></ul>Renal Association UK Renal Registry
  8. 8. Study population <ul><li>Incident RRT patients 1997-2004 in England and Wales </li></ul><ul><ul><li>Inclusion criteria </li></ul></ul><ul><ul><ul><li>From centres with >85% ethnicity data completeness † </li></ul></ul></ul><ul><ul><ul><li>Age >18 years </li></ul></ul></ul><ul><ul><ul><li>On Peritoneal dialysis at day 90 </li></ul></ul></ul><ul><ul><li>Exclusion criteria </li></ul></ul><ul><ul><ul><li>Missing data on age/gender/ cause of renal failure/ethnicity </li></ul></ul></ul><ul><ul><ul><li>Transplant prior to day 90 </li></ul></ul></ul><ul><ul><ul><li>Missing BP data in 1 st or 2 nd quarter </li></ul></ul></ul><ul><ul><ul><li>† No difference in survival or baseline characteristics of patients in centres with > 85 % and < 85% data </li></ul></ul></ul>Renal Association UK Renal Registry
  9. 9. Statistical analysis <ul><li>BP measurements </li></ul><ul><ul><li>Mean BP value in the 1 st /2 nd quarter of RRT </li></ul></ul><ul><ul><li>Systolic, Diastolic, Mean arterial and pulse pressure studied </li></ul></ul><ul><li>Cox regression model </li></ul><ul><ul><ul><li>BP as a continuous variable ( linear and non linear terms) </li></ul></ul></ul><ul><ul><ul><li>Factors adjusted in multivariate model </li></ul></ul></ul><ul><ul><ul><ul><li>Age, gender, ethnicity, cause of renal failure, haemoglobin, corrected calcium, phosphate, serum albumin </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Change of RRT modality as time dependent variable ( i.e. patients not censored at modality change) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Time to inclusion on Transplant waiting list as surrogate for co-morbidity </li></ul></ul></ul></ul>Renal Association UK Renal Registry
  10. 10. <ul><li>Outcome </li></ul><ul><ul><li>All cause mortality after day 90 </li></ul></ul><ul><ul><li>All patients followed until 31.12.05 or death </li></ul></ul><ul><li>Subgroup analyses </li></ul><ul><ul><li>Diabetics and non diabetics </li></ul></ul><ul><ul><li>Transplant waiting list registration status in 1 st year of RRT ( all cause mortality from 1 year after start of RRT) </li></ul></ul><ul><ul><ul><li>Waitlisted within 1 st year from start of RRT </li></ul></ul></ul><ul><ul><ul><li>Not waitlisted within the 1 st year from start of RRT </li></ul></ul></ul>Renal Association UK Renal Registry
  11. 11. Results (Study cohort) <ul><li>Cohort selection no. of patients </li></ul><ul><li>included </li></ul><ul><li>PD at day 90 ( centres >85 % ethnicity data) 3,991 </li></ul><ul><li>With data on ethnicity, cause of renal failure, 3,822 </li></ul><ul><li>previous transplant </li></ul><ul><li>With SBP/DBP data * 2,061 </li></ul><ul><li>With data on lab parameters and date of 2,035 </li></ul><ul><li>Transplant waitlisting </li></ul>* No difference in baseline characteristics and survival between those included and excluded except % males was more in excluded cohort (62.8% vs 58.2%) Renal Association UK Renal Registry
  12. 12. Baseline Characteristics Renal Association UK Renal Registry
  13. 13. P< 0.0002 P= 0.01 † Adjusted for age, gender, cause of renal failure, ethnicity, lab parameters, treatment modality, time to transplant waiting list Cox regression models † Renal Association UK Renal Registry
  14. 14. † Adjusted for age, gender, cause of renal failure, ethnicity, lab parameters, treatment modality, time to transplant waiting list † Cox Regression models P= 0.0007 P=0.05 Renal Association UK Renal Registry
  15. 15. Subgroup analyses – Time to transplant waiting list (WL) † Survival after 1 year, Adjusted for age, gender, cause of renal failure, ethnicity, lab parameters, treatment modality P =0.07 P= ns p =0.01 P = ns p =0.01 P = ns WL < 1 year (n=675) HR per 10 mmHg 1.14, 95 % CI 0.99-1.31 HR per 10 mmHg 1.29, 95 % CI 1.05-1.59 HR per 10 mmHg 1.33, 95 % CI 1.07-1.67 Renal Association UK Renal Registry
  16. 16. Subgroup analyses - Diabetes <ul><li>Diabetic – no association of any BP component with mortality </li></ul><ul><li>Non diabetic – U shaped for SBP and reverse J for MAP (as for entire study cohort) </li></ul>† Adjusted for age, gender, ethnicity, lab parameters,treatment modality, time to transplant waiting list Renal Association UK Renal Registry
  17. 17. Summary <ul><li>Pattern of association of BP and mortality was </li></ul><ul><ul><li>For the entire study population </li></ul></ul><ul><ul><ul><li>U shaped for SBP </li></ul></ul></ul><ul><ul><ul><li>Reverse J for MAP </li></ul></ul></ul><ul><ul><ul><li>No association for DBP and PP </li></ul></ul></ul><ul><ul><li>For those registered on the transplant waiting list within first year </li></ul></ul><ul><ul><ul><li>Linear for SBP, DBP, MAP </li></ul></ul></ul><ul><ul><ul><li>No association for PP </li></ul></ul></ul><ul><ul><li>For patients with diabetes </li></ul></ul><ul><ul><ul><li>No association with any BP components </li></ul></ul></ul>Renal Association UK Renal Registry
  18. 18. <ul><li>Strengths </li></ul><ul><ul><li>Largest study to date on PD patients </li></ul></ul><ul><ul><li>First to describe the association of BP and survival in patients on the transplant waiting list </li></ul></ul><ul><ul><li>Novel analytic strategy of adjusting for modality change allowed extended follow up of patients without censoring </li></ul></ul><ul><li>Limitations </li></ul><ul><ul><li>BP measurement not standardised </li></ul></ul><ul><ul><li>Lack of data on co-morbidity, residual renal function dialysis dose </li></ul></ul><ul><ul><li>No data on cardiac function or anti HT medications </li></ul></ul>Renal Association UK Renal Registry
  19. 19. Conclusions <ul><li>High and low SBP are risk factors for increased mortality in incident PD patients </li></ul><ul><li>Low SBP was not associated with increased mortality in a subgroup of patients activated early on the transplant waiting list </li></ul><ul><li>Association of low SBP and mortality seen in entire study cohort could reflect poor cardiac function/ health status </li></ul><ul><li>The BP associated with best survival may vary for different patient subgroups </li></ul>Renal Association UK Renal Registry
  20. 21. Baseline Characteristics

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