Adherence to anti-hypertensive therapy with perindopril-based single-pill versus free-pill combinations: a 10-year real-world analysis in Italy

Abstract Background/Introduction Despite the growing availability of blood pressure-lowering drugs, hypertension remains poorly controlled and a significant mortality cause worldwide. The silent course of the disease, suboptimal adherence, and complexity of therapeutic schedules are important factors in reducing the effectiveness of anti-hypertensive treatments at the population level. With the purpose of simplifying patients’ medication self-management, guidelines have strongly endorsed the use of anti-hypertensive therapy with single-pill combinations (SPCs). Perindopril (PER)-based SPCs, including both two- and three-drug combinations, have been available since 2008. Purpose We explored treatment adherence over 10 years in patients receiving PER-based regimens (SPC or free-pill combination) in Italy. Methods A retrospective real-world analysis was conducted on administrative databases covering 6.7 million Italian health-assisted residents. Among adults with hospitalization discharge diagnosis or exemption code for hypertension between 2010 and 2021, those with PER-based prescriptions were identified, considering combinations with amlodipine (AML) and/or indapamide (IND), either as SPC or free-pill or mixed (SPC+separate pill). The index-date (ID) was that of the first prescription of a PER-based regimen throughout the inclusion period. All patients with at least 12 months of available data before and after the ID were included. A cross-sectional analysis evaluated the yearly adherence for the period 2012-2021, calculating the proportion of days covered (PDC) by drug prescriptions on 1-year follow-up (PDC≥80% indicated high-adherence). Results Over 2012-2021, of 121,397 patients on a PER-based therapy, those treated with SPC ranged from 87% (during 2012) to 94.4% (during 2021), while free-pill and SPC+separate pill cohorts represented, respectively, 10.6-3.5% and 2.4-2.1% of all hypertensive patients. Over the decade, the proportion of adherent patients in SPC users was markedly higher than in free-pill and SPC+separate pill cohorts (Fig. 1). The sudden reduction of adherent patients during 2018-2019 was possibly due to a temporary shortage of PER/AML/IND as SPC in Italy from Nov-2018 to Mar-2019. Multivariate analysis showed that over 2012-2021 decade, free-pill and SPC+separate pill regimens resulted in significantly lower adherence (more than 80% reduction) than SPC formulation, while male gender and older age were predictive of better adherence (Table 1). Conclusions These findings from real clinical practice in Italy highlighted a growing attitude from clinicians to prescribe more manageable anti-hypertensive schemes based on SPC formulations, in line with current guidelines. The higher proportion of adherent patients among the users of PER-based SPCs corroborates the importance of alleviating pill burden, that is a key component in blood pressure control, and so in the reduction of hypertensive complications and cardiovascular risk.