OBJECTIVE: To investigate in a random comparison the capacity of an angiotensin converting enzyme inhibitor (fosinopril), and that of a long-acting dihydropiridine (nifedipine GITS) to modify the decay in renal function in patients with primary renal disease, exhibiting a progressive increase in serum creatinine during the previous 2 years.
METHODS: A randomized, open-label, multicenter study with a minimum follow-up of 3 years. A total of 241 patients were included in the study. All of them were hypertensive and had a 25% or at least 0.5 mg/dl increase in the value of serum creatinine during the 24 months prior to entering the study. Initial doses of fosinopril and nifedipine GITS were 10 and 30 mg respectively, and titration to 30 and 60 mg was performed if needed to obtain the expected blood pressure goal (< 140/90 mmHg). Furosemide, atenolol, and doxazosin were added as second, third, and fourth drugs if necessary, for blood pressure control. The primary end-point of the study was the appearance of double the serum creatinine values and/or the need to enter a dialysis programme. Secondary end-points were cardiovascular events, death, changes in 24 h proteinuria, and the evolution of serum creatinine. Data reflect the analysis performed by intention to treat.
RESULTS: Mean age of the group was 54 +/- 14, and 59% were males. Primary glomerulonephritis (31%), nephrosclerosis (26%) and polycystic kidney disease (19%) were the three most frequent diagnostic findings. After 3 years of follow-up, 21% (27/127) of patients treated with fosinopril, and 36% (40/112) of those receiving nifedipine GITS presented a primary end-point, (OR 0.47, 95% confidence intervals 0.26-0.84, P = 0.01). Renal survival was significantly better when fosinopril constituted the first step therapy (P = 0.002). These results did not seem to be influenced by the type of primary renal disease. Proteinuria decreased at the end of the study by a mean of 57% in the fosinopril group and increased by 7% in the group receiving dihydropiridine. Blood pressure control did not differ among groups for diastolic values. During follow-up, however, the patients receiving ACEi showed systolic blood pressure values 4-6 mmHg lower.
CONCLUSION: In patients with chronic renal failure and hypertension due to primary renal disease, fosinopril significantly differed from nifedipine GITS by its capacity to slow the progressive decay in renal function. The drugs also differed by their capacity to lower blood pressure. The better control, in particular of systolic blood pressure, in the fosinopril arm could have contributed in a relevant manner to the attainment of a better outcome when the ACEi was employed.