ACE I-ARB combination therapy not detrimental to severely hypertensive diabetics

1 September 2010

MedWire News: Australian researchers suggest that combined ACE inhibitor (ACE-I) and angiotensin receptor blocker (ARB) antihypertensive therapy does not produce more renal damage than monotherapy with either drug in diabetes patients with severe hypertension.

However, in diabetes patients with less severe hypertension, renal function significantly worsens when combination treatment is given instead of monotherapy, explain Jencia Wong (Royal Prince Alfred Hospital, Sydney, New South Wales) and colleagues.

The researchers measured the estimated glomerular filtration rates (eGFR) of 600 patients with stage 1 (blood pressure [BP] <160/100 mmHg, n=506) or stage 2 (BP ≥160/100 mmHg, n=94) hypertension, over a median follow-up period of 3.7 years.

During this period, all patients were treated with an ACE-I or an ARB (monotherapy, n=480), or with an ACE-I and an ARB (combination therapy, n=120).

Writing in the journal Diabetes, Obesity, and Metabolism, Wong et al report that among patients with stage 1 hypertension, renal function deterioration, defined as an eGFR decline of ≥20 ml/min from baseline, occurred more frequently among those taking combination therapy than among patients taking monotherapy, at 20.0% versus 10.7%.

However, among patients with stage 2 hypertension, the reverse was found, albeit nonsignificantly, with renal function deterioration occurring in 12.0% and 23.3% of patients taking combination therapy and monotherapy, respectively.

Furthermore, combination therapy did not increase the risk for macrovascular disease compared with monotherapy in any of the patients, and was in fact associated with a lower risk for ischemic heart disease and total macrovascular events.

Wong and colleagues propose that “severe hypertension may represent a situation of greater activation of damaging intrarenal renin angiotensin system.”

They add: “Thus more complete blockade may overshadow any potential damaging effects of combination therapy seen at lower blood pressures.”

The team concludes: “Given that hypertension control is paramount and in the spirit of primum non nocere, these data are reassuring should clinicians choose to use ACE-I and ARB combination therapy in the very hypertensive patients.”

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Diabetes Obes Metab 2010; Advance online publication