Reduction in microalbuminuria by calcium channel blockers in patients with type 2 diabetes mellitus and hypertension—A randomized, open‐label, active‐controlled, superiority, parallel‐group clinical trial

BACKGROUND: It has been suggested that renoprotection with calcium channel blockers (CCBs) may differ. This study aimed to compare the anti‐proteinuric effect of different CCBs in patients with type 2 diabetes (T2D). METHODS: A multicentre, randomized, open‐label, active‐controlled study was performed in seven centres in Korea. A total of 74 patients with T2D and microalbuminuria treated with renin‐angiotensin system (RAS) blockers were randomized to a cilnidipine 10 mg treatment (n=38) or amlodipine 5 mg treatment (n=36). RESULTS: Urine albumin to creatinine ratio (ACR) reduction was similar between the two groups at 12 weeks (−53.0±123.2 mg/g in cilnidipine group and −35.7±83.6 mg/g in amlodipine group, P=.29) or 24 weeks (−57.3±106.9 mg/g in cilnidipine group and −20.0±110.4 mg/g in amlodipine group, P=.24). In a subgroup analysis, cilnidipine treatment showed a larger ACR reduction than amlodipine treatment at 12 weeks (−84.7±106.8 mg/g in cilnidipine group and −9.5±79.2 mg/g in amlodipine group, P=.01) and 24 weeks (−84.0±111.7 mg/g in cilnidipine group and 14.6±119.4 mg/g in amlodipine group, P=.008), particularly in patients with a longer duration of diabetes more than 10 years. CONCLUSIONS: Cilnidipine did not show any additional anti‐albuminuric effect compared with amlodipine in patients with T2D and microalbuminuria treated with an RAS blocker. However, the anti‐albuminuric effect of cilnidipine might differ according to the duration of diabetes.