Diabetes Research Today is a free monthly online journal that collates and summarizes the latest research about Diabetes, including details on insulin, type i, type ii, diet, treatment, prevention.

Differential effects of beta-blockers on albuminuria in patients with type 2 diabetes.

Bakris GL, Fonseca V, Katholi RE, McGill JB, Messerli F, Phillips RA, Raskin P, Wright JT, Waterhouse B, Lukas MA, Anderson KM, Bell DS,

Rush University Medical Center, Chicago, IL 60612, USA. gbakris@earthlink.net

Increases in the cardiovascular risk marker microalbuminuria are attenuated by blood pressure reduction using blockers of the renin-angiotensin system. Such changes in microalbuminuria have not been observed when beta-blockers are used. A prespecified secondary end point of the Glycemic Effects in Diabetes Mellitus Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial was to examine the effects of different beta-blockers on changes in albuminuria in the presence of renin-angiotensin system blockade. Participants with hypertension and type 2 diabetes were randomized to either metoprolol tartrate (n=737) or carvedilol (n=498) in blinded fashion after a washout period of all antihypertensive agents except for angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Blinded medication was titrated to achieve target blood pressure, with a-5 month follow-up period. The current analysis examined microalbuminuria, using spot urine albumin:creatinine, in participants who had values at screening and trial end. A greater reduction in microalbuminuria was observed for those randomized to carvedilol (-16.2%Delta; 95% confidence interval, -25.3, -5.9; P=0.003). Of those with normoalbuminuria at baseline, fewer progressed to microalbuminuria on carvedilol versus metoprolol (20 of 302 [6.6%] versus 48 of 431 [11.1%], respectively; P=0.03). Microalbuminuria development was not related to differences in blood pressure or achievement of blood pressure goal (68% carvedilol versus 67%, metoprolol). Presence of metabolic syndrome at baseline was the only independent predictor of worsening albuminuria throughout the study (P=0.004). Beta-blockers have differential effects on microalbuminuria in the presence of renin-angiotensin system blockade. These differences cannot be explained by effects on blood pressure or alpha1-antagonism but may relate to antioxidant properties of carvedilol.

Published 24 November 2005 in Hypertension, 46(6): 1309-15.
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