Introduction: Cardiovascular diseases (CVD) represent the first cause of mortality in western countries. Hypertension and dyslipidemia are strong risk factors for CVD, and are prevalent either alone or in combination. Although effective substances for the treatment of both factors are available, there is space for optimization of treatment regimens due to poor patient's adherence to medication, which is usually a combination of several substances. Adherence decreases with the number of pills a patient needs to take. A combination of substances in one single-pill (single pill combination, SPC), might increase adherence, and lead to a better clinical outcome.
Aim: We conducted a meta-analysis to compare the effect of SPC with that of free-combination treatment (FCT) in patients with either hypertension, dyslipidemia or the combination of both diseases under conditions of daily practice.
Methods: Studies were identified by searching in PubMed from November 2014 until February 2015. Search criteria focused on trials in identical hypertension and/or dyslipidemia treatment as FCT therapy or as SPC. Adherence and persistence outcome included proportion-of-days-covered (PDC), medication possession ratio (MPR), time-to treatment gap of 30 and 60 days and no treatment gap of 30 days (y/n). Clinical outcomes were all cause hospitalisation, hypertension-related hospitalisation, all cause emergency room visits, hypertension-related emergency room visits, outpatient visits, hypertension-related outpatient visits, and number of patients reaching blood pressure goal. Randomized clinical studies were excluded because they usually do not reflect daily practice.
Results: 11 out of 1.465 studies met the predefined inclusion criteria. PDC ≥ 80% showed an odds ratio (OR) of 1.78 (95% CI: 1.30-2.45; p = 0.004) after 6 months and an OR of 1.85 (95% CI: 1.71; 2.37; p < 0.001) after ≥ 12 months in favour to the SPC. MPR ≥ 80% after 12 months also was in favour to SPC (OR 2.13; 95% CI: 1.30; 3.47; p = 0.003). Persistence was positively affected by SPC after 6, 12, and 18 months. Time to treatment gap of 60 days resulted in a hazard ratio (HR) of 2.03 (95% CI: 1.77; 2.33, p < 0.001). The use of SPC was associated with a significant improvement in systolic blood pressure reduction, leading to a higher number of patients reaching individual blood pressure goals (FCT vs SPC results in OR = 0.77; 95% CI: 0.69; 0.85, p < 0.001). Outpatient visits, emergency room visits and hospitalisations, both overall and hypertension-related were reduced by SPC: all-cause hospitalisation (SPC vs FCT: 15.0% vs 18.2%, OR 0.79, 95% CI 0.67; 0.94, p = 0.009), all-cause emergency room visits (SPC vs FCT: 25.7% vs 31.4%, OR 0.75, 95% CI 0.65; 0.87, p = 0.001) and hypertension related emergency room visits (SPC vs FCT: 9.7% vs 14.1%, OR 0.65, 95% CI 0.54; 0.80, p < 0.001).
Conclusions: SPC improved medication adherence and clinical outcome parameter in patients suffering from hypertension and/or dyslipidemia and led to a better clinical outcome compared to FCT under conditions of daily practice.
Keywords: Adherence; Cardiovascular disease; Clinical outcome; Dyslipidemia; Free-combination treatment; Hypertension; Single pill combination.