Effect of Water Intake and Water Restriction on Total Kidney Volume in Autosomal Dominant Polycystic Kidney Disease

Effect of Water Intake and Water Restriction on Total Kidney Volume in Autosomal Dominant Polycystic Kidney: The HYDRA Study

The objective of this study is to measure the influence of both short term water restriction and high water intake on total kidney volume, measured by Magnetic Resonance Imaging (MRI) scan in Autosomal Dominant Polycystic Kidney Disease (ADPKD) patients.

Patients will be randomized to either water restriction for 3 hours or high water intake (20 ml/kg) for 1 hour. Before intervention and after intervention patients will have an MRI scan of the kidneys to measure the total kidney volume (TKV) (differentiated in cortex, medulla and cyst volume). The objective is to identify whether water restriction or high water load will change the TKV. Secondly investigators will analyze different biomarkers (aldosterone, renin, vasopressin/copeptin, urine- and blood-osmolarity) before and after the intervention.

Inclusion Criteria:

• ADPKD
• CKD stage 1-3

Exclusion Criteria:

• Patients treated with diuretics
• Pregnancy
• Change in antihypertensive treatment < 1 month
• Any condition contraindicating MR scan