Vitamine C status bij patiënten met chronische nierinsufficiëntie

Rationale: Patients with kidney failure have various physical complaints and laboratory abnormalities. Vitamin C deficiency may play a causal role and contribute to cramping, iron deficiency and immunity disorders. Unfortunately, there is scarce information in the literature on vitamin C deficiency and vitamin C intake in patients with kidney failure. Also the exact prevalence of vitamin C deficiency and its related symptoms in patients with kidney failure have not yet been systematically examined. Finally, it is not known what the exact cause of vitamin C deficiency is. It is plausible that various mechanisms play a role and that the intensity of the dialysis treatment is an important factor.

Objective: The goal of this study is to assess the prevalence of vitamin C deficiency in patients with end stage renal disease (Endogenous Creatinin Clearance <20 ml/min) and in patients on various forms of renal replacement therapy: kidney transplantation (NTx), peritoneal dialysis (PD), conventional (CHD) and nocturnal center hemodialysis (NCHD).

Study design: Cross-sectional observational study in different patient groups.

Study population: Predialysis patients, NTx, PD, CHD, and NCHD patients of 18 years or older.

Main study parameters/endpoints: 1. Predialysis patients: plasma vitamin C level; 2. NTx patients: plasma vitamin C level; 3. PD patients: plasma vitamin C level, 4. CHD patients: plasma vitamin C levels before, during and after dialysis; 5. NCHD patients: plasma vitamin C levels before, during and after dialysis. In all groups vitamin C intake will be assessed using a 24-hour recall questionnaire.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: This research has no disadvantages for the participants, except drawing of a limited volume of blood. Blood sampling in predialysis, NTx and PD patients will take place during regular visits to the outpatient clinic and no extra venipuncture is necessary; the total blood volume for these patients is 10 ml (incl. 5 ml for storage). Blood sampling in CHD and NCHD patients is performed during the regular dialysis session. The total blood volume in these patients is 20 ml (3 x 5 ml + 5 ml for storage). The food questionnaires are taken during regular visits and will cost no additional time. Participation in this study will take little to no extra time. The results of the study could contribute to the quality of treatment of the patients.

Vitamin C deficiency may play a role in the symptoms of patients with chronic kidney failure and eventually renal replacement therapy

1 year

Bloodsamples