'Using single-pill combinations rather than multiple pills may represent a simple and potentially low-cost intervention that could substantially reduce the global burden of death and disability related to hypertension,' the authors of a retrospective population-based Canadian study conclude.
The researchers compared clinical outcomes and medication adherence for antihypertensive fixed-dose combination (FDC) therapy and multi-pill combination therapy.
They examined the medical records of 13,350 patients aged 66 years and older in Ontario who were prescribed either an angiotensin-converting enzyme inhibitor or an angiotensin II-receptor antagonist, plus a thiazide diuretic, as either single tablets or an FDC, between April 2004 and December 2014. Patients were followed for 5 years or until 31 March 2015.
To analyse adherence to treatment, the researchers assessed the time to the first instance of medication discontinuation, defined as any break in treatment within 150% of the previous days’ supply, and the total proportion of days covered.
The median time to the first instance of medication discontinuation was 191 days in the FDC group compared to 150 days in the multi-pill group (p<0.01). Over the entire study period, the proportion of days covered was 70% in the FDC group, which was significantly greater than the 42% observed in the multi-pill group (p<0.01).
In the intention-to-treat analysis, the composite primary outcome of death from any cause or hospitalisation for acute myocardial infarction, heart failure or stroke occurred at a significantly lower rate in the FDC group than in the multi-pill group, at 3.4 events per 100 person-years compared with 3.9 events per 100 person-years (HR 0.89, 95% CI 0.81–0.97, p<0.01). In the on-treatment analysis there was no significant difference in outcomes between the groups.
'Most patients need more than one medication to control blood pressure, but it is difficult to regularly take multiple medications. Single-pill combinations allow more intense treatment with simpler regimens. Our study is the first to show that single-pill treatment for hypertension is associated with improved outcomes,' said lead author of the study, Dr Amol Verma.