Combination Therapy of Angiotensin Converting Enzyme Inhibitor and Angiotensin AT1 Receptor Antagonist in Diabetic Nephropathy

BackgroundThe present study was undertaken to determine whether combination therapy of angiotensin converting enzyme inhibitor (ACEI) and angiotensin AT1 receptor antagonist (ARA) is a useful tool for reducing albuminuria in diabetic nephropathy.MethodsThirty-four subjects with diabetic nephropathy were enrolled in the present study. All the subjects had hypertension and urinary albumin index (UAI) < 1,000 mg/g creatinine. They were divided into three groups. Group 1 of 16 subjects was initially treated with imidapril (5–10 mg). Group 2 of eight subjects had losartan (50–100 mg) added to consecutive therapy with imidapril. Group 3 of 10 subjects had imidapril (5–10 mg) added to consecutive therapy with losartan. Blood pressure and UAI were determined before and 3 and 6 months after the start of the present study.ResultsBlood pressure was significantly decreased in Group 1 subjects. Blood pressure was also reduced in Groups 2 and 3, but its reduction was not significant. Imidapril significantly reduced UAI in Group 1, from 213.1 ± 46.6 to 111.6 ± 35.6 (p < 0.001) and 114.5 ± 35.4 mg/g creatinine (p < 0.01) 3 and 6 months after imidapril treatment, respectively. The addition of losartan further reduced UAI in Group 2, who had been treated with imidapril. UAI decreased from 328.8 ± 87.3 to 185.3 ± 51.4 (p < 0.05) and 244.8 ± 88.3 mg/g creatinine 3 and 6 months after the addition of losartan, respectively. In contrast, the addition of imidapril to losartan therapy did not alter UAI in Group 3.ConclusionThese results indicate that the addition of ARA to consecutive therapy with ACEI augments a protective effect against the progression of diabetic nephropathy.