Effect of three months' treatment with irbesartan on blood and pulse pressure of hypertensive type 2 diabetic patients: open, observational study in 31,793 patients

Retrospective analysis of real-world efficacy of angiotensin receptor blockers versus other classes of antihypertensive agents in blood pressure management

BACKGROUND

Efficacy of blood pressure (BP) lowering may differ between clinical trials and what is observed in clinical practice. These differences may contribute to poor BP control rates among those at risk.

OBJECTIVE

We conducted an observational study to determine the BP-lowering efficacy of angiotensin receptor blocker (ARB) versus non-ARB-based antihypertensive treatments in a large Canadian primary care database.

METHODS

We analyzed the South Western Ontario database of 170,000 adults (aged >18 years) with hypertension persisting with antihypertensive medication for ≥9 months. Routine standard of care office BP was measured using approved manual aneroid or automated devices. BP <140 mm Hg and/or <90 mm Hg ≤9 months after treatment initiation, persistence (presence of initial antihypertensive prescription at the first, second, third, and fourth year anniversary) with antihypertensive therapy, and the presence of a cardiovascular (CV) event (ie, myocardial infarction) were studied.

RESULTS

After 9 months of monotherapy, 28% (978 of 3490) of patients on ARBs achieved target BP versus 27% (839 of 3110) on angiotensin-converting enzyme inhibitors (ACEIs) (P > 0.05), 26% (265 of 1020) on calcium channel blockers (CCBs) (P > 0.05), 21% (221 of 1050) on β-blockers (P = 0.002), and 19% (276 of 1450) on diuretics (P = 0.001). Attainment rates were significantly higher with irbesartan (38%; 332 of 873) versus losartan (32%; 335 of 1047; P = 0.01), valsartan (19%; 186 of 977; P = 0.001), and candesartan (25%; 148 of 593; P = 0.001). BP goal attainment rates were significantly higher when ARB was compared with non-ARB-based dual therapy (39%; 1007 of 2584 vs 31%; 1109 of 3576; P = 0.004); irbesartan + hydrochlorothiazide (HCTZ) was significantly higher than losartan + HCTZ (36%; 500 of 1390 vs 20%; 252 of 1261; P = 0.001). For patients receiving dual or tri-therapy, 48% (667 of 1390) of patients receiving irbesartan reached target BP versus 41% to 42% for losartan (517 of 1261), valsartan (194 of 462), and candesartan (168 of 401) (P = 0.001 for each). After 4 years, persistence rates were not statistically different among ARB, CCB, and diuretic monotherapies, but appeared somewhat higher with ACEIs and β-blockers (78%, 78%, 79%, 91%, and 84%, respectively). Persistence was not significantly different between irbesartan and losartan monotherapy (76% for both; P > 0.05), but was significantly higher with irbesartan + HCTZ versus losartan + HCTZ (96% vs 73%, respectively; P = 0.001). Patients treated with ARBs reported fewer CV events than those receiving ACEIs or CCBs (4.3% vs 7.0% and 11.0%, respectively; P < 0.001). Within the ARB class, the lowest rate was with irbesartan (3.0% vs 4.6%-5.0% for other ARBs; P < 0.02).

CONCLUSIONS

In this real-world setting, hypertensive adults treated with ARBs versus β-blockers or diuretics were more likely to have evidence-based target BP recorded. In addition, patients using ARBs versus ACEIs or CCBs had fewer reports of CV events.

Fixed combination of irbesartan and hydrochlorothiazide in the management of hypertension

Approximately 25% of the adult population worldwide is hypertensive and thus at risk of cardiovascular morbidity and mortality. Despite the availability of many antihypertensive drugs, at least 50% of patients do not achieve blood pressure (BP) targets and thus remain at increased cardiovascular risk. Fixed-dose (FD) irbesartan/hydrochlorothiazide (HCTZ) is an antihypertensive combination therapy approved for the treatment of patients whose BP is not adequately controlled on monotherapy and for initial treatment of patients likely to need multiple drugs to achieve their BP goal. The efficacy and tolerability of FD irbesartan/HCTZ has been demonstrated in both patient populations in large multicenter studies. In patients failing antihypertensive monotherapy, FD irbesartan/HCTZ (150/12.5 mg) has been shown to be more effective than FD valsartan/HCTZ (80/12.5 mg) and at least comparable to FD losartan/HCTZ (50/12.5 mg). In patients with moderate or severe hypertension receiving FD irbesartan/HCTZ as initial therapy, this combination achieved more rapid BP reductions compared with irbesartan monotherapy and enabled a greater proportion of patients with severe hypertension to achieve their BP target. FD irbesartan/HCTZ is thus a valuable addition to the clinician’s armamentarium for the management of hypertension and should help more patients achieve their BP target.

Predictors of blood pressure response to angiotensin receptor blocker/diuretic combination therapy: a secondary analysis of the irbesartan/hydrochlorothiazide blood pressure reductions in diverse patient populations (INCLUSIVE) study

The secondary analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) clinical trial investigated whether baseline demographic and clinical variables are predictive of different degrees of blood pressure reduction following an angiotensin II receptor blocker/diuretic treatment regimen. Irbesartan/hydrochlorothiazide and other angiotensin receptor blocker combinations with a diuretic have been shown to be effective in reducing systolic blood pressure in a diverse patient population previously uncontrolled on monotherapy. Ordinary least squares regression analysis was performed on the intent-to-treat population of the INCLUSIVE study to identify variables predictive of variations in blood pressure changes in response to irbesartan/hydrochlorothiazide combination therapy. Higher baseline systolic blood pressure, female sex, type 2 diabetes, and statin therapy were found to be predictive of additional blood pressure lowering with this combination. The impact of higher baseline systolic blood pressure and diabetic state on changes in systolic blood pressure were diminished in female patients compared with male patients. In conclusion, a significant correlation may exist between certain clinical/demographic characteristics and the extent of the therapeutic response with irbesartan/hydrochlorothiazide treatment.