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Canadian Journal of Cardiology

Primary Prevention of Sudden Cardiac Death With Device Therapy in Urban and Rural Populations

Published:January 16, 2017DOI:https://doi.org/10.1016/j.cjca.2016.10.020

      Abstract

      Background

      Implantable cardioverter defibrillators (ICDs) have shown benefit in reducing mortality in patients with heart failure, after myocardial infarction, and those with reduced ejection fraction. We sought to explore the use of this therapy in specialized heart function clinics, in rural and urban locations.

      Methods

      This was a retrospective cohort study performed in 3 specialized heart function clinics in Nova Scotia, 2 of which were in rural locations. All patients with an initial left ventricular ejection fraction ≤ 35% were included from 2006 to 2011. Rates of referral, ICD implantation, and mortality were compared between urban and rural groups.

      Results

      There were 922 patients included in the study; 636 patients in the urban clinic, 286 in the rural locations. Referral rates were higher in the urban clinic compared with the rural locations (80.4% vs 68.3%; P = 0.024). Refusal rates for referral were higher in the rural locations (13.7% vs 2.1%; P < 0.0001). Higher referral rates were associated with urban location (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.01-3.26; P = 0.047), and younger age (OR, 0.96; 95% CI, 0.93-0.99; P = 0.003); lower referral rates for women was observed (OR, 2.29; 95% CI, 1.13-4.63; P = 0.021). Mortality was significantly associated with older age, lack of referral, presence of comorbidities (renal failure, diabetes, peripheral vascular disease) and a rural location.

      Conclusions

      Specialized heart function clinics have a high rate of appropriate referral for primary prevention ICDs, but referral rates for this life-saving therapy remain lower in rural jurisdictions. This disparity in access to care is associated with increased mortality and might require particular attention to prevent unnecessary deaths.

      Résumé

      Introduction

      Les défibrillateurs cardioverteurs implantables (DCI) ont démontré des avantages dans la réduction de la mortalité chez les patients souffrant d’insuffisance cardiaque, après un infarctus du myocarde et chez ceux dont la fraction d’éjection est réduite. Nous avons cherché à étudier l’utilisation de cette thérapie dans des cliniques spécialisées en fonction cardiaque, en milieu rural et en milieu urbain.

      Méthodes

      Il s’agissait d’une étude rétrospective de cohorte réalisée dans 3 cliniques spécialisées en fonction cardiaque de la Nouvelle-Écosse, dont 2 en milieu rural. De 2006 à 2011, tous les patients dont la fraction d’éjection ventriculaire gauche initiale était ≤ 35 % étaient inclus. Les taux d’aiguillage, l’implantation de DCI et la mortalité étaient comparés entre les groupes en milieu urbain et les groupes en milieu rural.

      Résultats

      L’étude comptait 922 patients, dont 636 de la clinique en milieu urbain, et 286 des cliniques en milieu rural. Les taux d’aiguillage étaient plus élevés dans la clinique en milieu urbain que dans les cliniques en milieu rural (80,4 % vs 68,3 % ; P = 0,024). Les taux de refus d’aiguillage étaient plus élevés en milieu rural (13,7 % vs 2,1 % ; P < 0,0001). Les taux d’aiguillage plus élevés étaient associés au milieu urbain (ratio d’incidence approché [RIA], 1,81 ; intervalle de confiance [IC] à 95 %, 1,01-3,26 ; P = 0,047), et à un plus jeune âge (RIA, 0,96 ; IC à 95 %, 0,93-0,99 ; P = 0,003) ; les taux d’aiguillage plus faibles étaient observés chez les femmes (RIA, 2,29 ; IC à 95 %, 1,13-4,63 ; P = 0,021). La mortalité était significativement associée à un âge plus avancé, à l’absence d’aiguillage, à la présence de comorbidités (insuffisance rénale, diabète, maladie vasculaire périphérique) et au milieu rural.

      Conclusions

      Les cliniques spécialisées en fonction cardiaque ont un taux élevé d’aiguillage convenable pour les DCI en prévention primaire, mais les taux d’aiguillage pour les traitements de sauvetage restent plus faibles dans les milieux ruraux. Cette disparité dans l’accès aux soins est associée à une mortalité accrue et nécessiterait une attention particulière pour prévenir les décès inutiles.
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