Atherosclerosis 217 (2011) 479–485 Contents lists available at ScienceDirect Atherosclerosis jo ur nal homep age : www.elsevier.com/locate/atherosclerosis Cost-effectiveness of enhancing adherence to therapy with statins in the setting of primary cardiovascular prevention. Evidence from an empirical approach based on administrative databases Giovanni Corrao a,∗ , Lorenza Scotti a , Antonella Zambon a , Gianluca Baio a , Federica Nicotra a , Valentino Conti a,b , Stefano Capri c , Elena Tragni d , Luca Merlino e , Alberico L. Catapano d,f,g , Giuseppe Mancia h a Department of Statistics, Unit of Biostatistics and Epidemiology, University of Milano-Bicocca, Milan, Italy b Regional Centre for Pharmacovigilance, Lombardy Region, Milan, Italy c Institute of Economics, Cattaneo - LIUC University, Castellanza, Italy d Centre of Pharmacoepidemiology and Pharmacoutilization, University of Milan, Milan, Italy e Operative Unit of Territorial Health Services, Lombardia Regional Council, Milan, Italy f Department of Pharmacological Sciences, University of Milano, Milan, Italy g Multimedica IRCCS, Milan, Italy h Department of Clinical and Preventive Medicine, University of Milano-Bicocca, Milan, Italy a r t i c l e i n f o Article history: Received 29 October 2010 Received in revised form 12 April 2011 Accepted 12 April 2011 Available online 22 April 2011 Keywords: Adherence Administrative database Cohort study Cost-effectiveness Ischemic heart disease Statins a b s t r a c t Aim: To estimate the cost-effectiveness of enhancing adherence to statin therapy across a large population without signs of pre-existing cardiovascular disease. Methods and results: The cohort of 84,262 patients aged 40–79 years, resident in the Italian Lombardia Region, who were newly treated with statins during 2002–2003, was followed from index prescription until 2007. During follow-up the 1397 patients who experienced a hospitalization for ischemic heart disease (IHD) were identified (outcome). Adherence from index prescription until the date of hospital- ization or censoring was measured by the proportion of days covered by the therapy with statins (PDC). Cost-effectiveness of enhancing adherence was measured through the incremental cost-effectiveness ratio (ICER). The robustness of findings was tested in a sensitivity analysis. Interventions to increase the average level of adherence from 45% (baseline) to 50% (“soft” intervention) or to 90% (“hard” interven- tion) reduced the number of patients who experience IHD (from 38.9 to 38.4 or 35.8 events every 10,000 person-year, respectively), and increased the cost for drug therapy (from 1326 to 1452 or 2626 thousand euros every 10,000 person-year, respectively). ICER ranged from 243 (95% CI: 230–259) to 413 (391–439) thousand euros every 10,000 person-year for the soft and hard interventions, respectively. Conclusions: Interventions aimed at enhancing adherence to statin therapy in the setting of primary cardiovascular prevention might offer important benefits in reducing the risk of cardiovascular outcome, but at a substantial cost. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Large randomized clinical trials (RCTs) have shown that statins reduce cardiovascular morbidity and mortality in patients with dyslipidaemia [1], even in those without established cardiovascu- lar disease (CVD) [2]. Much less is known about the effectiveness of ∗ Corresponding author at: Dipartimento di Statistica, Università degli Studi di Milano-Bicocca, Via Bicocca degli Arcimboldi, 8, Edificio U7, 20126 Milano, Italy. Tel.: +39 02 64485854; fax: +39 02 64485899. E-mail address: giovanni.corrao@unimib.it (G. Corrao). lipid-lowering treatment in the setting of routine community care [3]. Although full therapeutic potential after one or two years of continuous treatment has been documented [4], inadequate adher- ence to statin therapy continues to contribute to treatment shortfall [5–8]. Consequently the efficacy shown in RCTs may be less rele- vant in usual community care, as shown by recent observational investigations [9–14]. Previous cost-effectiveness analyses [15–21] have shown that statin therapy is generally cost-effective for secondary preven- tion and for high-risk primary prevention, but rarely focus on the population-level impact or average cost-effectiveness across het- erogeneous populations [22]. Also, it is unclear whether improving 0021-9150/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2011.04.014