Changes in plasma lipids during renin-angiotensin system blockade by combination therapy (enalapril plus valsartan) in patients with diabetes and hypertension

There is experimental evidence of an interaction between the angiotensin system and lipid metabolism. The aim of this study was to evaluate whether a block of the angiotensin system achieved both by ACE inhibition and angiotensin II-ATl receptor blockade could affect the plasma lipid profile and, if so, what relationship exists between these possible changes and glucose metabolism and blood pressure. In 50 patients with type 2 diabetes and hypertension, treated with diabetes drugs and enalapril, we evaluated the glycemic and lipid profile together with the HOMA insulin-resistance index, blood pressure and microalbuminuria at baseline and 3 months after the addition of valsartan. At the second evaluation, blood pressure was reduced as expected, whereas the glycemic profile, the HOMA index, and the body mass index were unchanged. Total cholesterol, LDL-c, and apoprotein B were reduced during combination therapy (P = 0.003, P = 0.001, and P = 0.004, respectively), plasma HDL-c was slightly though significantly increased (P = 0.024), whereas apoprotein A and trialyceride levels did not change. After adjustment for the insulin resistance index and for blood pressure, the reduction of LDL-c and apoprotein B and the increase in HDL-c remained significant. The variation in lipid profile was not related to the changes in blood pressure. Moreover, the addition of valsartan to enalapril was associated with a reduction in microalbuminuria, which remained significant after adjustment for LDL-c or blood pressure changes. Thus, the greater degree of renin-angiotensin system blockade or specific pharmacodynamic effects of valsartan could account for the changes in plasma lipid profile observed in this study.