title: Socioeconomic Inequalities in Statin Adherence Under Universal Coverage: Does Sex Matter?
abstract: Previous research shows that low socioeconomic position (SEP; especially low income) is associated with statin nonadherence. We investigated the relationship between SEP and statin adherence in a country with universal coverage using group-based trajectory modeling in addition to the proportion of days covered.
  
  
  
  Using data from Finnish healthcare registers, we identified 116 846 individuals, aged 45 to 75 years, who initiated statin therapy for primary prevention of cardiovascular disease. We measured adherence as proportion of days covered over an 18-month period since initiation and identified different adherence patterns based on monthly adherence with group-based trajectory modeling. When adjusted for age, marital status, residential area, clinical characteristics, and copayment, low SEP was associated with statin nonadherence (proportion of days covered <80%) among men (eg, lowest versus highest income quintile: odds ratio, 1.41; 95% confidence interval, 1.32-1.50; basic versus higher-degree education: odds ratio, 1.18; 95% confidence interval, 1.13-1.24; unemployment versus employment: odds ratio, 1.17; 95% confidence interval, 1.10-1.25). Among women, the corresponding associations were different (P<0.001 for sex-by-income quintile, sex-by-education level, and sex-by-labor market status interactions) and mainly nonsignificant. Results based on adherence trajectories showed that men in low SEP were likely to belong to trajectories presenting a fast decline in adherence.
  
  
  
  Low SEP was associated with overall and rapidly increasing statin nonadherence among men. Conversely, in women, associations between SEP and nonadherence were weak and inconsistent. Group-based trajectory modeling provided insight into the dynamics of statin adherence and its association with SEP.
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.). emma.aarnio@uef.fi.
authors.forename: Emma
authors.initials: E
authors.lastname: Aarnio
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.).
authors.forename: Janne
authors.initials: J
authors.lastname: Martikainen
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.).
authors.forename: Aaron N
authors.initials: AN
authors.lastname: Winn
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.).
authors.forename: Risto
authors.initials: R
authors.lastname: Huupponen
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.).
authors.forename: Jussi
authors.initials: J
authors.lastname: Vahtera
authors.affiliation: From the Department of Clinical Pharmacology, Tykslab, Turku University Hospital, Finland (E.A., R.H.); School of Pharmacy, University of Eastern Finland, Kuopio, Finland (E.A., J.M.); Department of Health Policy and Management, School of Public Health (A.N.W.) and Division of Pharmaceutical Outcomes and Policy, Eshelman School of Pharmacy (M.J.K.), University of North Carolina at Chapel Hill; Department of Pharmacology, Drug Development and Therapeutics (R.H., M.J.K.) and Department of Public Health (J.V., M.J.K.), University of Turku, Finland; and Turku University Hospital, Finland (J.V.).
authors.forename: Maarit J
authors.initials: MJ
authors.lastname: Korhonen
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000191:economics* / Q000209:etiology / Q000517:prevention & control*; D016527:Drug Costs; D011307:Drug Prescriptions; D004522:Educational Status; D004651:Employment / Q000191:economics; D005260:Female; D005387:Finland; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000191:economics* / Q000627:therapeutic use*; D007182:Income; D016015:Logistic Models; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011322:Primary Prevention / Q000191:economics* / Q000379:methods; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D013997:Time Factors; D019472:Universal Health Insurance / Q000191:economics*
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors
keywords: cardiovascular diseases; income; medication adherence; primary prevention; sex; socioeconomic position