Study design and study population The study design was a prospective randomized intervention study in a single center. A randomization process was performed to assign participants to either the aliskiren-treatment group or the negative control group in an open-label design. The duration of the study period was 24 weeks as the time frame for treatment. Duration of treatment was decided based on previous studies using RAS inhibitor 13,25. Aliskiren was administered to patients in the treatment group at an oral dose of 150-300 mg per day. Medication administration started after a baseline study with a dose of 150 mg of aliskiren, which was escalated to 300 mg of aliskiren at 4 weeks after evaluation of tolerability and the presence of adverse effects as angioedema, gastrointestinal symptoms, rash, gout, hypotension, and renal stones. The patients stopped taking aliskiren if serious adverse events such as angioedema or allergic reactions definitely related to the medication developed. Dose reduction was considered in cases with development of hyperkalemia, elevation of serum creatinine to twice baseline, symptomatic hypotension, gout, or renal stones. Dose reduction to 150 mg after escalation was performed on the decision of the investigators if the patient complained of discomfort and side effects that were probably related to the medication.