Effects of Beta Blockers on Albuminuria in Diabetes
Not all beta blockers have the same effect on cardiovascular risk factors in patients with diabetes. The Glycemic Effects in Diabetes Mellitus Carvedilol-Metoprolol Comparison in Hypertensives (GEMINI) trial found that, in the presence of an angiotensin-converting enzyme (ACE) inhibitor or an angio-tensin-receptor blocker (ARB), the beta blocker carvedilol (e.g., Coreg medication, Glaxo-SmithKline) preserved glycemic control, whereas metoprolol generic (e.g., Toprol generic, Astra-Zeneca) did not. Carvedilol also reduced the risk of albuminuria, another marker of cardiovascular risk, by 47%.
As many as 40% of type-2 diabetic patients have microalbuminuria. Recent studies suggest that lowering both blood pressure and albuminuria levels may have better cardiovascular and renal effects than just lowering blood pressure.
Of 388 patients assigned to receive carvedilol, 6.6% of those with normal albumin levels at screening developed microalbuminuria, compared with 11% of 542 patients receiving metoprolol tablet.
In the cohort without microalbumin-uria, similar numbers of patients needed a calcium antagonist to achieve blood pressure goals. More patients taking drug carvedilol required low-dose hydro-chlorothiazide; this was also true in patients without microalbuminuria. Even with a higher rate of diuretic use, these patients still had better glycemic control.
In a separate analysis, patients with the metabolic syndrome at the baseline evaluation had a 168% increase in the odds of experiencing a worsening in albuminuria over the five months of follow-up.
