Fixed-dose combination cardiovascular drugs improves adherence but does not make a significant impact on long-term cardiovascular outcomes, suggests a recent study.
The three-year open-label randomised controlled trial included 513 adults (aged 18-79) at high risk of cardiovascular disease – established cardiovascular disease or give year risk greater than 15% -who were recommended for treatment with antiplatelet, statin and two or more blood pressure lowering drugs. Participants were randomised to continue usual care or fixed-dose combination treatment, with two versions available: aspirin 75 mg, simvastatin 40 mg, and lisinopril 10 mg with either atenolol 50mg or hydrochlorothiazide 12.5 mg. All drugs in both treatment arms were prescribed by their usual general practitioners. The primary outcomes were self-reported adherence to recommended drugs, and mean change in blood pressure and low-density lipoprotein cholesterol at 12 months.
Adherence to all four recommended drugs was greater among fixed-dose combination than usual care participants at 12 months (81% versus 46%). Adherence for each drug type at 12 months was high in both groups but especially in the fixed dose combination group: for antiplatelet treatment it was 93% for fixed dose combination versus 83% for usual care; for statin 94% versus 89%; for combination blood pressure lowering 89% versus 59%, and for any blood pressure lowering, 96% versus 91%. Self-reported adherence was highly concordant with dispensing data (dispensing of all four recommended drugs: 79% fixed dose combination versus 47%usual care).
There was no statistically significant improvement in risk factor control between the fixed-dose combination and usual care groups over 12 months: the difference in systolic blood pressure was
−2.2 mm Hg (−4.5 versus −2.3), in diastolic blood pressure−1.2 mm Hg (−2.1 versus −0.9) and in low density lipoprotein cholesterol −0.05 mmol/L (−0.20 versus −0.15). The number of participants with cardiovascular events or serious adverse events was similar in both treatment groups (fixed-dose combination 16 versus usual care 18, 99 versus 93, respectively).
The researchers note that their results ‘support the potential usefulness of fixed dose combination based care in people at high risk of cardiovascular disease, particularly in the large group currently receiving few recommended cardiovascular preventative drugs’ but advise that ‘further trials are needed that are set in primary care and emulate local cardiovascular disease risk management, prescribing, and dispensing practices’.
Current guidelines recommend concomitant use of aspirin, statin, and blood pressure-lowering agents in several high risk patient groups.