Contents lists available at ScienceDirect European Journal of Internal Medicine journal homepage: www.elsevier.com/locate/ejim Original Article Comorbidity assessment for mortality risk stratification in elderly patients with acute coronary syndrome Juan Sanchis a, ⁎ , Meritxell Soler a , Julio Núñez a , Vicente Ruiz b , Clara Bonanad a , Francesc Formiga c , Ernesto Valero a , Manuel Martínez-Sellés d , Francisco Marín e , Arancha Ruescas f , Sergio García-Blas a , Gema Miñana a , Emad Abu-Assi g , Héctor Bueno h , Albert Ariza-Solé i a Servei de Cardiologia, Hospital Clínic Universitari de València, INCLIVA, Universitat de València, CIBERCV, València, Spain b Facultat d'Infermeria, Universitat de València, València, Spain c Unitat de Medicina Geriàtrica, Servei de medicina Interna, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain d Servicio de Cardiología, Hospital Universitario Gregorio Marañón, CIBERCV, Universidad Complutense, Universidad Europea, Madrid, Spain e Servicio de Cardiologı'a, Hospital Virgen de la Arrixaca, IMIB-Arrixaca, CIBERCV, El Palmar, Murcia, Spain f Departament de Fisioteràpia, Universitat de València, València, Spain g Servicio de Cardiologia, Hospital Alvaro Cunqueiro, Vigo, Pontevedra, Spain h Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain i Servei de Cardiologia, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain ARTICLE INFO Keywords: Acute coronary syndrome Elderly Comorbidity ABSTRACT Background: The Charlson's is the most used comorbidity index. It comprises 19 comorbidities, some of which are infrequent in elderly patients with acute coronary syndrome (ACS), while some others are manifestations of cardiac disease rather than comorbidities. Our goal was to simplify comorbidity assessment in elderly non-ST- segment elevation ACS patients. Methods: The study group consisted of 1 training (n = 920, 76 ± 7 years) and 1 testing (n = 532; 84 ± 4 years) cohorts. The end-point was all-cause mortality at 1-year follow-up. Comorbidities were assessed selecting those medical disorders other than cardiac disease that were independently associated with mortality by multivariable analysis. Results: A total of 130 (14%) patients died in the training cohort. Six comorbidities were predictive: renal failure, anemia, diabetes, peripheral artery disease, cerebrovascular disease and chronic lung disease. The in- crease in the number of comorbidities yielded a gradient of risk on top of well-known clinical predictors: ≥3 comorbidities (27% mortality, HR = 1.90, 95% CI 1.20–3.03, p = .006); 2 comorbidities (16% mortality, HR = 1.29, 95% CI 0.81–2.04, p = .30); and 0–1 comorbidities (7.6% mortality, reference category). The dis- crimination accuracy (C-statistic = 0.80) and calibration (Hosmer-Lemeshow test, p = .20) of the predictive model using the 6 comorbidities was comparable to the predictive model using the Charlson index (C-sta- tistic = 0.80; Hosmer-Lemeshow test, p = .70). Similar results were reproduced in the testing cohort (≥3 co- morbidities: 24% mortality, HR = 2.37, 95% CI 1.25–4.49, p = .008; 2 comorbidities: 14% mortality, HR = 1.59, 95% CI 0.82–3.07, p = .20; 0–1 comorbidities: 7.5% reference category). Conclusion: A simplified comorbidity assessment comprising 6 comorbidities provides useful risk stratification in elderly patients with ACS. 1. Introduction Comorbidities are highly prevalent in elderly patients with acute coronary syndrome (ACS) [1–7]. The fact that they may confound prognosis evaluation of the primary illness is a matter of concern [8]. Several comorbidity indices have been introduced for prognosis as- sessment, among which the Charlson index is the most commonly used [9]. However, it seems unlikely that a single tool, based on a historical https://doi.org/10.1016/j.ejim.2019.01.018 Received 23 October 2018; Received in revised form 18 January 2019; Accepted 29 January 2019 Abbreviations:ACS, Acute coronary syndrome ⁎ Corresponding author at: Servei de Cardiologia, Hospital Clínic Universitari, Blasco Ibáñez 17, 46010 València, Spain. E-mail address: sanchis_juafor@gva.es (J. Sanchis). European Journal of Internal Medicine xxx (xxxx) xxx–xxx 0953-6205/ © 2019 Published by Elsevier B.V. on behalf of European Federation of Internal Medicine. Please cite this article as: Sanchis, J., European Journal of Internal Medicine, https://doi.org/10.1016/j.ejim.2019.01.018