Risk-benefit aspects of antihypertensive drugs

Irbesartan for the treatment of hypertension in patients with the metabolic syndrome: a sub analysis of the Treat to Target post authorization survey. Prospective observational, two armed study in 14,200 patients

Objectives

The metabolic syndrome is a cluster of cardiovascular risk factors leading to an increased risk for the subsequent development of diabetes and cardiovascular morbidity and mortality. Blocking the renin-angiotensin system has been shown to prevent cardiovascular disease and delay the onset of diabetes. Irbesartan is an angiotensin receptor blocker (ARB) which has been shown to possess peroxisome proliferator-activated receptor gamma (PPARγ) activating properties, and to have a favorable metabolic profile. Current discussion is whether the addition of small doses of hydrochlorothiazide changes this profile. Therefore the efficacy, safety and metabolic profile of Irbesartan either as monotherapy or in combination therapy was assessed in patients with the metabolic syndrome in a large observational cohort in primary care.

Research design and methods

Multicenter, prospective, two-armed, post authorization study over 9 months in 14,200 patients with uncontrolled hypertension with and without the metabolic syndrome (doctors' diagnosis based on the Adult Treatment Panel III criteria 2001). Blood pressure was measured sphygmomanometrically and cardiovascular risk factors making up the criteria for the metabolic syndrome were assessed.

Main outcome measures

Systolic (SBP) and diastolic (DBP) blood pressure reduction, – response, and – normalization (systolic and diastolic), changes in fasting glucose, waist circumference (abdominal obesity), serum triglycerides and HDL cholesterol as well as the proportion of patients fulfilling the criteria for the metabolic syndrome. Number and nature of adverse events (AEs).

Results

After 9 month the use of Irbesartan in monotherapy resulted in a significant reduction of blood pressure (SBP: -26.3 ± 10.1 mmHg/DBP-13.0 ± 6.6 mmHg, both p < 0.0001) in patients with the metabolic syndrome. This was accompanied by a reduction in cardiovascular risk factors: HDL cholesterol (+3.6 ± 7.2 mg/dl in men, +3.8 ± 6.5 mg/dl in women, both p < 0.0001), serum triglycerides (-28.6 ± 52.1 mg/dl, p < 0.0001), fasting blood glucose (-8.4 ± 25.1 mg/dl, p < 0.0001) and waist circumference (-2.4 ± 11.9 cm in men, -1.2 ± 14.2 in women, both p < 0.0001) were significantly improved. Irbesartan combination therapy (12.5 mg HCTZ) in patients with the metabolic syndrome: blood pressure reduction (SBP: -27.5 ± 10.1 mmHg/DBP: -14.1 ± 6.6 mmHg, both p < 0.0001), improvement in HDL cholesterol (+4.0 ± 6.8 mg/dl in men, +3.4 ± 6.8 in women, both p < 0.0001), triglycerides (-34.1 ± 52.6 mg/dl, p < 0.0001), fasting blood glucose (-10.0 ± 24.7, p < 0.0001) and waist circumference (-3.2 ± 12.7 cm in men, -1.7 ± 14.4 in women, both p < 0.0001). Tolerability was excellent: only 0.6% of patients experienced an AE.

Conclusion

There was a significant improvement in blood pressure and metabolic risk factors as a result of Irbesartan treatment. There was no evidence of a difference between monotherapy and combination therapy with regard to the cardiovascular risk profile.

The effect of irbesartan in reducing cardiovascular risk in hypertensive type 2 diabetic patients: an observational study in 16,600 patients in primary care

OBJECTIVES

As arterial hypertension substantially increases the risk of premature death, cardiovascular disease and renal insufficiency in patients with type 2 diabetes, effective and safe antihypertensive therapy is of importance. Therefore, the effect of irbesartan as monotherapy, or in fixed combination with hydrochlorothiazide, on blood pressure, metabolic parameters and microalbuminuria and the safety and tolerability of the drug were assessed.

RESEARCH DESIGN AND METHODS

Multicentric, prospective, open phase IV study over 3 months in 16,600 patients with the clinical diagnoses of hypertension and type 2 diabetes. Blood pressure was measured sphygmometrically and albuminuria was assessed with semi-quantitative urine dipsticks.

MAIN OUTCOME MEASURES

Systolic (SBP) and diastolic (DBP) blood pressure reduction, proportion of patients with microalbuminuria and cardiovascular risk calculated based on the SCORE score, each after a follow-up of 3 months compared to baseline. Number and nature of adverse events (AEs).

RESULTS

The sample consisted of 51.3% men, mean age was 62.2+/-10.7 years, 53.9% of patients were overweight and 26.4% were obese. Mean SBP/DBP decrease after 3 months was 22.3/11.2 mmHg. The BP lowering effect was similar in the analyses of various subgroups (according to age group, sex, presence of micro- or macrovascular complications). Irbesartan treatment reduced the percentage of patients with microalbuminuria from 45.6% to 30.6% at 3 months (32.9% relative reduction). Metabolic parameters (lipids, blood glucose, HbA1c) and weight were improved significantly or showed trends for improvement, respectively. The mean 10-year cardiovascular risk as calculated with the SCORE score was decreased from a baseline value of 9.8% to 5.7% (-58% relative reduction). Tolerability was excellent: only 0.3% experienced an AE.

CONCLUSIONS

Treatment with irbesartan in patients with concomitant hypertension and type 2 diabetes led to large blood pressure reductions. In view of the renoprotective effect documented by the reduced rate of patients with albuminuria, and the improvement of further metabolic parameters, these changes translate into a reduction of cardiovascular risk.