Effect of strict blood pressure control on proteinuria in renal patients treated with different antihypertensive drugs

Background. The severity of proteinuria is the main predictive factor in th e progression of renal failure in chronic nephropathies. Therefore, action aimed at reducing proteinuria should be a priority in the treatment of thes e patients. Various antihypertensive drugs, in particular the angiotensin-c onverting enzyme inhibitors:(ACEIs), have a greater antiproteinuric effect, although it is difficult to establish whether this is due only to their ef fect on arterial blood pressure (BP) or to other mechanisms associated with blockade of the renin-angiotensin system (RAS). Methods. The evolution of proteinuria after two successive treatment period s was studied prospectively for 2 years in 22 patients with chronic glomeru lonephritis. In period I, which lasted for 12 months, BP was strictly contr olled (<125/75mmHg) and the patients received random and double-blind treat ment with a <beta>-blocker (betaB), atenolol; a non-dihydropyridine calcium channel blocker (CCB), verapamil; an ACEI, trandolapril; or a fixed combin ation of the latter two. In period II, all of the patients received treatme nt openly for an additional 12 months with a fixed combination of verapamil + trandolapril at half the dose of the preceding period, to obtain convent ional control of BP at < 140/90 mmHg. Results. The mean level for basal SBP/DBP was 136<plus/minus>14/86 +/-7 mmH g, which decreased in period I to 121 +/- 15/76 +/-8 mmHg (P=0.01) and to 1 24 +/-5/78 +/-8 mmHg (P < 0.05) at 6 and 12 months of treatment, respective ly. There were no differences in the BP reached in the four therapy groups, however, proteinuria only decreased in the patients treated with trandolap ril alone or in combination with verapamil. In period II, BP levels rose to 134<plus/minus>10/84 +/-8 mmHg (P<0.05); this increase in BP was accompani ed by an increase in proteinuria in those patients who had received the ACE I alone or in combination in the previous period, while in patients previou sly treated with a <beta>B or a CCB, proteinuria decreased. ill spite of th e increase in BP. Conclusions. With equal BP control, treatment with the ACEI trandolapril al one, or in combination with a CCB, has a greater antiproteinuric effect tha n that obtained with other antihypertensive drugs, but this effect is atten uated if BP is not strictly controlled.