Saving Residual Renal Function Among Haemodialysis Patients Receiving Irbesartan

Angiotensin II receptor blockers (ARB) are known to preserve kidney function among patients with kidney diseases and reduced renal function, but not among haemodialysis patients.

Haemodialysis patients often lose residual renal function after initiating dialysis leading to worsened quality of life, increased morbidity and mortality.

In this study an ARB is investigated in a double blind, randomised, parallel group, placebo controlled manner to see, if this ARB can save residual renal function among haemodialysis patients. Potential cardiovascular benefits of the treatment are also addressed.

Haemodialysis patients often lose residual renal function rather quickly after initiation of dialysis - average loss is 30 % per year. Loss of residual kidney function leads to deteriorating quality of life, more morbidity and a higher mortality. Many causes to this has been identified, but no one has - to my knowledge - addressed saving of residual renal function among haemodialysis patients so far.

Hypothesis: Irbesartan can reduce loss of residual kidney function among haemodialysis patients and left ventricular hypertrophy and arterial stiffness is less pronounced after 1 year of treatment.

Methods: 80 patients are randomised to receive either irbesartan, an angiotensin II receptor blocker (ARB), or placebo for 1 year. Residual renal function will be estimated before and one-two weeks after initiating project medicine, in order to estimate the acute effect of ARB on residual renal function in this study population. Thereafter, glomerular filtration rate (GFR) and urine volume will be determined after 3, 6, 9 and 12 months giving a regression line for each patient. 8 dialysis units will be recruiting patients.

Investigations:

* creatinine-urea-clearance by 24h urine collection
* applanation tonometry
* cardiac output
* echocardiography
* QoL questionnaire
* endocrinological and cardiovascular markers in blood and urine

Perspectives: It is well-known that ceased urine production has a tremendous negative effect on the quality of life of haemodialysis patients. Lately it was shown that residual renal function has greater impact than dialysis dose on morbidity as well as mortality. Among peritoneal dialysis patients in Asia an angiotensin-converting enzyme inhibitors (ACEI) or an ARB saved residual renal function, but preservation of renal function has not been addressed in haemodialysis patients, and ACEI or ARB are only prescribed to roughly 15 % of these.

If this study confirms our hypothesis the growing population of haemodialysis patients should be offered irbesartan.

Eligibility Criteria:
Inclusion Criteria:

* Haemodialysis patient
* Haemodialysis treatment for maximum 12 months
* \> 18 years old
* informed consent
* urine volume \> 300 ml / 24 hours
* contraception if fertile woman

Exclusion Criteria:

* Systolic blood pressure \< 110 mm Hg
* Able to comprehend the aims of the project and follow instructions
* Allergy to irbesartan/ACE-inhibitors/ARBs
* Myocardial infarction or unstable angina pectoris during the last 3 months
* Ejection fraction \< 30 %
* Pregnancy