Insulin resistance (IR) in
chronic renal failure (CRF) is well-known. In this randomized-controlled study, we aimed to compare the effect of
doxazosin and
amlodipine on IR in patients with CRF. Fifteen patients with CRF (male/female: 5/10, mean age: 46 +/- 13 years) and 9 controls (male/female: 3/6, mean age: 35 +/- 8 years) were included. Patients and controls had no family history of
diabetes mellitus. Homeostasis model assessment (HOMA) was calculated as a marker of IR. Patients were grouped randomly to
doxazosin (n = 8; 2-4 mg/day) and
amlodipine (n = 7; 5-10 mg/day) arms. Baseline biochemical analysis (fasting serum
glucose, BUN,
creatinine,
uric acid,
cholesterol and
cholesterol subgroups) and parameters related with
insulin metabolism (
insulin,
C peptide, HOMA) were similar between
amlodipine and
doxazosin groups. There was no difference in age, gender and body mass index among study groups. The follow-up time was 12 weeks. Patients with CRF had higher HOMA (1.83 +/- 0.55 vs 1.00 +/- 0.36, p = 0.001), fasting
insulin (8.06 +/- 1.98 vs 4.46 +/- 1.31 IU/l, p < 0.001) and serum
triglyceride levels (197 +/- 136 vs 112 +/- 67 mg/dl, p = 0.04) as compared to controls. Serum
HDL cholesterol levels were significantly lower in patients with CRF than controls (40 +/- 10 vs 57 +/- 14 mg/dl, p = 0.02). HOMA significantly decreased after
doxazosin (1.91 +/- 0.45 vs 1.41 +/- 0.21, p = 0.02), however, no difference was found after
amlodipine. Also, fasting
insulin levels were decreased after a 12-week
doxazosin therapy from 8.17 +/- 1.22 vs 6.58 +/- 0.84 IU/l, p = 0.02), but no change was seen after
amlodipine.
Lipid parameters did not significantly change during the study period in 2 groups. No adverse effect requiring
drug discontinuation was observed during the 12-week period in the study groups. In conclusion,
doxazosin decreases IR in patients with CRF, whereas
amlodipine has no effect. This may be of advantage in the treatment of
hypertension in this group of patients for preventing some long-term complication of IR.