Abstract
Background
Comparative effectiveness studies are common in patients with nonvalvular atrial fibrillation
(NVAF) and chronic kidney disease (CKD), but the accuracy of current thromboembolic
(n = 4) and bleeding (n = 3) prediction scores used for risk adjustment are uncertain
in these patients because previous studies have included few CKD patients.
Methods
This was a retrospective cohort study, using Cox models adjusted for time-varying
coefficients, of nonanticoagulated adults with incident NVAF and kidney function (defined
into Kidney Disease: Improving Global Outcomes [KDIGO] CKD categories) between 2002 and 2013.
Results
Of 58,451 patients (mean age 66 years, 31.3% with CKD) followed for a median of 31
months, 21.3% died, 12.6% had a thromboembolic event (4.2 per 100 patient-years),
and 7.8% had a major bleed (2.6 per 100 patient-years). There were graded associations
between kidney function and all-cause mortality (adjusted hazard ratio [aHR], 1.88
[95% confidence interval (CI), 1.79-1.98] for very high vs low risk KDIGO category),
major bleeding (aHR, 1.61 [95% CI, 1.47-1.76]), and thromboembolic events (aHR, 1.13
[95% CI, 1.04-1.23]). All 7 prediction scores had significantly poorer c statistics
in patients with CKD: 0.50-0.59; all P < 0.0001 compared with those with normal kidney function (c statistics 0.69-0.70
for the 4 thromboembolic risk scores and 0.60-0.68 for the 3 bleeding risk scores).
Inclusion of KDIGO category did not improve calibration or discrimination statistics
for current prediction scores.
Conclusions
Existing NVAF risk scores exhibit poor discrimination in patients with CKD, limiting
their utility for clinical decision-making or for risk adjustment in comparative effectiveness
studies. Although CKD is an independent risk factor for adverse events, adding KDIGO
class to current risk scores did not improve their performance.
Résumé
Introduction
Les études d’efficacité comparatives incluant des patients atteints de fibrillation
auriculaire non valvulaire (FANV) et de néphropathie chronique (NC) sont relativement
fréquentes. Cependant, l’exactitude des scores prévisionnels actuels des événements
thromboemboliques (n = 4) et des hémorragies (n = 3) utilisés aux fins d’ajustement
du risque demeure incertaine du fait que trop peu de patients atteints de NC ont jusqu’ici
participé à des études.
Méthodes
Il s’agissait d’une étude de cohorte rétrospective pour la période comprise entre
2002 et 2013 effectuée à l’aide du modèle de régression de Cox, ajusté en fonction
de coefficients variables dans le temps, chez des adultes atteints de FANV et de NC
ne recevant pas de traitement anticoagulant (degrés d’insuffisance rénale définis
selon la classification fournie dans les lignes directrices Kidney Disease: Improving Global Outcomes [KDIGO]).
Résultats
Des 58 451 patients (âge moyen de 66 ans; 31,3 % des patients atteints de NC) suivis
pendant une période médiane de 31 mois, 21,3 % sont décédés, 12,6 % ont été victimes
d’un événement thromboembolique (4,2 par 100 années-patients) et 7,8 % ont subi une
hémorragie grave (2,6 par 100 années-patients). Une gradation du risque a été établie
entre la fonction rénale et la mortalité de toutes causes (rapport de risques instantanés
ajustés [RRIa] de 1,88 [intervalle de confiance (IC) à 95 % : 1,79 à 1,98] entre les
patients à risque très élevé par rapport à ceux à faible risque selon la classification
KDIGO), l’hémorragie grave (RRIa de 1,61 [IC à 95 % : 1,47 à 1,76]) et les événements
thromboemboliques (RRIa de 1,13 [IC à 95 % : 1,04 à 1,23]). Comparativement aux patients
dont la fonction rénale était normale (statistiques c de 0,69 à 0,70 pour les 4 scores
de risque d’événement thromboembolique et de 0,60 à 0,68 pour les 3 scores de risque
d’hémorragie), les statistiques c étaient significativement inférieures chez les patients
atteints de NC pour l’ensemble des 7 scores prévisionnels, soit 0,50 à 0,59; P < 0,0001 pour l’ensemble. L’ajout de la classification KDIGO n’a donc pas permis
d’améliorer la calibration ni la discrimination statistique des scores prévisionnels
actuels.
Conclusions
Les scores de risque actuellement utilisés pour les patients atteints de FANV ne permettent
pas une discrimination statistique efficace chez les patients atteints de NC, ce qui
limite leur utilité aux fins de prise de décision en clinique et d’ajustement du risque
dans le cadre des études d’efficacité comparatives. On sait que la présence d’une
NC constitue un facteur de risque indépendant d’événements indésirables, mais l’ajout
de la classification KDIGO aux scores de risque actuellement utilisés n’a pas permis
d’améliorer leur utilité.
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Article info
Publication history
Published online: September 30, 2016
Accepted:
August 22,
2016
Received:
July 19,
2016
Footnotes
See editorial by Hart et al., pages 211–213 of this issue.
See page 251 for disclosure information.
Identification
Copyright
© 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
